Geo-Chicago 2016: Sustainability and Resiliency in Geotechnical Engineering

Methods of soil improvement that consider both the physical/mechanical properties and the environmental/geochemical aspects of soils have been studied and developed in recent years. This is due to the necessity of a nonhazardous soil improvement method that can alleviate the environmental concerns of current soil improvement methods. Several considerations such as the use of biological organisms and biopolymers have been researched for their applicability in soil improvement. In this study the use of casein proteins derived from bovine milk is purposed as a possible soil improvement material. With its biological origin and characteristics, casein treated soil is regarded to be harmless and safe to the environment. Additionally, with the large and growing amount of dairy wastes, this soil improvement method could serve as a possible sink for such wastes. Results of casein treatment have shown that a definite increase in strength is observed when casein based binders are integrated into the soil.

A stoichiometric model was developed for predicting the amount of carbonate precipitation and gas production from two different biogeotechnical soil improvement techniques: enzyme-induced hydrolysis of urea and microbial denitrification. Carbonate precipitation via hydrolysis of urea, or ureolysis, and via dissimilatory nitrate reduction, or denitrification, has been shown in laboratory testing to improve the shear strength and cyclic resistance of granular soils. Desaturation via denitrification has also shown the ability to improve cyclic resistance. For effective implementation of these techniques in the field, it is important to understand the material requirements necessary to achieve the desired degree of improvement. Therefore, a model for predicting carbonate precipitation and gas production from these techniques was developed using stoichiometry, thermodynamics, and microbial growth patterns and calibrated with laboratory test data. The model will facilitate the implementation of cost-effective, non-intrusive, and sustainable ground improvement.

Global warming and unsustainable land development are known to be major triggers promoting geotechnical hazards such as farmland and coastal erosion, yellow dust, and desertification. New forestry practices, such as encouraging forests in dry land areas, are simple measures that can remove more carbon from the atmosphere and prevent the spread of deserts. Numerous global agencies and companies are thus contributing to anti-desertification movements. However, tree planting alone is not an ideal solution given that it takes approximately 2~3 years for stabilization. It is thus imperative to develop innovative technology that can promote vegetation growth and improve soil erosion resistance. In this study, a unique soil treatment and anti-desertification method is developed using environmentally friendly biogenic biopolymers. Biopolymers can effectively strengthen soil and improve durability. In particular, anionic-hydrophilic biopolymers delay water evaporation, thereby retaining a higher soil moisture condition compared to untreated soil. For technical verification, series of laboratory investigations (i.e. water erosion test, seed germination and growth) were performed by applying target biopolymers to soil specimens. The results indicate that environmentally-friendly biopolymer treatment is highly effective in improving both vegetation growth (3 times faster) and soil erosion resistance (less than 2%), compared to a untreated condition.

Treating sandy soil using a microbial induced calcite precipitation (MICP) process has been studied substantially in the past years. However, it is still a challenge to apply the MICP or other similar approach to treat fine-grained soil. In this paper, difficulties and challenges of using biocement to treat fine-grained soil such as marine clay are discussed. Different approaches adopted so far are reviewed. Some preliminary data are presented to illustrate the possibilities of improving the shear strength properties of clay using biotreatment or a MICP process through a so-call bioencapsulation method. However, the mechanisms behind the improvement in soil properties are yet to be fully understood. The cost-effectiveness is another issue that has yet to be addressed.

Plants are sensitive to many different forms of stimuli, and they respond to many well-known environmental conditions such as temperature, light quality, moisture, and gravity, among others. Electro-culture or electro-farming consists of stimulation by electric fields applied in the soil in order to improve the germination rate, growth rate, yields and crop quality. It has been demonstrated that the treatment also protects plants from diseases; even so, this technology remains poorly studied. Here, we study the electro-culture process for Arabidopsis thaliana using IrO₂-Ta₂O₅ | Ti as a dimensional stable anode (DSA) with a titanium cathode. We expect to accelerate the germination and growth rate of this plant’s cotyledons, leaves, and roots in the early stages of growth. This process is beneficial due to the fact that the ions undergo electro-migration and permeate the nutrients across the seeds. Furthermore, a decrease in pH occurs nearby the DSA via electrolysis of the water during the electro-culture process (pH = 1), and we observe the generation of OH radicals during this electrolysis when the seed is exposed to low electric fields in a short time with direct currents (less than 5V in 1 hour).

Effects of sea level rising and increasing storm severity create a more damage prone environment for coastal regions. Large storm surges can be devastating to coastal infrastructure, damaging roads, utilities, structures, and endangering the lives of local residents. Coastal sand dunes act as a primary defense to wave action, making their resiliency of the utmost importance. Microbial induced calcite precipitation (MICP) offers a potentially sustainable alternative to seawall and revetment type solutions which destroy entire ecosystems in order to protect cities or other areas of interest. Bio-cementation has been shown to improve the strength and stiffness of unsaturated sand. The study presented herein displays the behavior of MICP treated coastal sand when subjected to wave action. Two wave tank tests were conducted to assess the change in measured erosion for untreated sand and moderately cemented sand. To quantitatively measure the reduction in erosion, 3-D morphology was observed using a laser scanner before and after subjecting the sand to wave action. Acoustic wave gauges were used to monitor the input wave functions and the breaking waves on the soil surface. Further understanding of the erosion reduction potential of MICP treated sand increases the feasibility of in-situ application to coastal sand dunes.

Microbial induced calcium carbonate precipitation (MICP) has attracted attention as a sustainable means of soil improvement in recent years. The addition of discrete randomly distributed fibers has been used in practice to stabilize soils and to improve their mechanical properties. In this study, the effect of randomly distributed discrete fiber on the mechanical properties of MICP-treated soil was investigated. Specimens were prepared at different fiber ratios. Full contact flexible molds were used to prepare the MICP-treated sand samples. Unconfined compression strength (UCS) tests were conducted. SEM images were used to analyze the binding effect of fiber. The results showed that improvements in shear strength, ductility, and failure strain were achieved with fiber addition in the MICP-treated sand. The UCS and shear strength increased with fiber content up to a fiber content of 0.3%. The UCS of MICP-treated sand at the fiber content is nearly 100% higher than that without addition of fiber. The failure strain of MICP-treated sand at the fiber content is triple higher than that without addition of fiber. Residual strengths of MICP-treated sand at the fiber content are still near 100 kPa, compared to no residual strength for that of MICP-treated sand without fiber. The inclusion of fibers increases the residual strength occurring after peak stress and decreases the brittle behavior of the MICP-treated sand.

Recent interests in the bio-mediated soil alterations show a concerted focus on taking advantage of multi-physical mechanisms to seek innovative solutions to emerging challenges facing civil engineers. This paper explores the use of X-ray computed tomography (CT) to characterize the microbially induced calcite precipitation (MICP), where micro-organisms play an active role in catalyzing urea hydrolysis and inducing chemical precipitation of calcite, resulting in the reduction of porosity and permeability and improvement of strength and stiffness. The soil specimens were prepared with full contact flexible molds (FCFM). Cultured Sporosarcina pasteurii was used to grow biofilms. X-ray CT images of bio-treated soil specimens show its potential of characterization of spatial distribution of calcite precipitation. A macroscopic reactive-transport process was simulated focusing on the assessment and prediction of calcite precipitation. Calibrated against the experimental results of the average calcite precipitation in certain regions of the specimen, the numerical simulations indicate that modest uniformity is possible as observed in the experiments and may be addressed by conventional reactive transport modelling.

Bio-mineralization is an environment-friendly technology to improve soil engineering properties. One of common bio-mineralization processes is microbially induced calcite precipitation (MICP). A series of laboratory tests was conducted to produce solidification of the specimen having an estimated unconfined compressive strength (UCS) of more than several MPa, and investigate the influence of varies factors on soil properties treated with MICP. A solidification test was conducted using a syringe (30 mL) on different particle size of Mikawa sand (mean diameter: 0.6mm) and Toyoura sand (mean diameter: 0.2mm) using local ureolytic bacteria: Parahadobactor sp. isolated in Japan. The bacteria were grown up for 72 hours to increase the optical density (OD) of 600 nm (OD₆₀₀). The cementation media was added and the solidification test was conducted until 14 days. After that, needle penetration tests were conducted to obtain the estimated UCS value of the specimen. The results indicated that the estimated UCS value was exceeded 3 MPa for three Mikawa sand samples: (1) sample treated by 1.0g of bacteria re-injected bacterial solution after 7 days, (2) sample treated by 1.0g of bacteria without re-injection after 7 days, and (3) sample treated with 0.1g of bacteria with re-injection.

Bio-cementation is a promising method for the natural improvement of potentially liquefiable soil deposits (e.g., loose saturated sands). In the improvement process a bacterium that can be found naturally in soil deposits is fed urea. The bacterium consumes and breaks down the urea to form ammonium and carbonate. In the presence of calcium, calcium carbonate will precipitate at particle contacts and act as a cementitious agent to solidify the deposit. Moreover, experimental tests show that bio-cemented sand exhibits more ductile behavior than chemically cemented sand. This is a desirable response from an engineering point of view, since brittle failure is often catastrophic and occurs without warning. The scope of this study is to investigate the response of bio-cemented sand using the discrete element method (DEM). This numerical method is capable of simulating behavior of granular materials based upon the basic particle-scale physics of the system of interest. A new cementation model is proposed that replicates the presence of cement between soil particles. This bond is able to capture the progressive contact dissolution between two soil particles and associated nonlinear response. Triaxial samples were built and the aforementioned bond was applied to the contact points within the assembly. Samples with and without cementation are sheared and their stress-strain responses compared in terms of soil strength and stiffness. The effects of several bonding parameters are investigated and the relative contributions of multiple physical mechanisms to system response are considered.

Fine sands have shown that they are susceptible to liquefaction. There are many soil improvement methods that are effective in improving the shear strength and stiffness of fine sand but they often have limitations due to the soil characteristics, such as permeability. Microbial induced calcite precipitation (MICP) has been shown to be a natural and effective liquefaction mitigation method for clean fine sands. Although this method is effective, there may be limitations in implementing MICP in situ. In this study, the permeability reduction from MICP is investigated to understand its implications for field implementation of MICP treatments. Fine sand specimens have been treated to different cementation levels, estimated using nondestructive shear wave velocity measurements. Permeability of treated samples is measured using a constant head permeameter. Utilizing the permeability results of the treated specimens, numerical simulations of the MICP treatments are evaluated by creating a constant head difference between an injection and extraction well and observing the water velocity changes within the domain.

The effect of pH increasing ability of plant-derived urease to induce the precipitation of calcium phosphate compounds (CPCs) as CPC-biogrout (CPC-Bio) and addition of powder materials to induce the precipitation of CPCs as CPC-chemical grout (CPC-Chem) was examined separately using unconfined compressive strength (UCS) test for applying as novel, eco-friendly ground improvement methods. Initially, Toyoura sand test pieces were cemented only from CPC solutions made from stock solutions of calcium acetate and di-potassium phosphate. Subsequent sand test pieces were cemented by different concentrations of urea and CPC solution, and concentration fixed watermelon seeds extract. All test pieces were cured in an airtight container at high humidity at 25°C. Furthermore, the UCS on sand test pieces cemented with same stock solutions mentioned above with different powders such as tricalcium phosphate (TCP), magnesium phosphate (MgP), calcium carbonate (CC) and magnesium carbonate (MgC) were conducted. Maximum UCS of greater than 100 kPa was obtained after 28 days of curing for both CPC-Bio and CPC-Chem and obtained UCS was higher than the UCS of test pieces made only from CPC. pH for optimal cementation was around 8.0 and the best Ca/P ratio in CPC solutions producing the highest cementation was 0.5 for CPC-Bio.

Different stabilization methods for improving soil behavior are commonly used to control slope stability problems in dams, levees and embankments. The present study demonstrates the use of biopolymer soil mixtures as a sustainable slope stabilization technique. Expansive clayey soils with low and high plasticity characteristics were collected from representative dam embankments located in the Dallas-Fort worth (DFW) area in Texas. The experimental study consists of mixing the collected soil with a commercially available biopolymer (guar-gum), at 0.25%, 0.5%, 1%, and 1.5% concentrations by weight. Strength and swell parameters of mixtures were obtained by direct shear test and swell pressure tests respectively. Results obtained indicate that the addition of biopolymer increases the shear strength and the swelling phenomenon of the soil. The 0.5% biopolymer soil mixture presents the optimum concentration based on its high strength and low swell potential. Strength parameters for both, non-reinforced soil and biopolymer reinforced soil (0.5% mixture) are used to conduct slope stability analysis using the limit equilibrium approach. The application of biopolymer reinforced soil substantially increased the factor of safety against shallow slope failures. This research highlights the adaptability of biopolymers in enhancing the strength parameters and providing a safe sustainable solution.

The study uses microbial enrichment cultures to enhance CaCO₃ precipitation around soil particles for strength augmentation. Soil samples were collected from a landslide site near PinKuang River, Hsindian. Enrichment cultures from soil samples using Thermus medium can generate alkaline products, which raised the pH from 7.8 to 9.3 and kept there for over a month. Bacteria strains isolated from these enrichments can also increase the surrounding pH from 7.8 to 9.0 in average. Calcium was discovered on the surface of bio-treated sample by electron spectroscopy for chemical analysis system (ESCA), and the treated specimens reduced almost a half of the penetration depth in penetration test. The results from this study may be applied to ground improvement of natural slope in the future.

Chemo-mechanical couplings in geomaterials have received increasing attention in recent years for a number of applications, ranging from the stability of slopes and coastal structures to geological CO₂ sequestration. Chemical processes may result in strengthening or weakening effects, the latter being particularly critical for safety assessment in civil and energy engineering applications. In this work, coupling of chemical and mechanical processes in cemented soils and rocks is investigated by means of a micro-structure inspired model, consisting of an assembly of grains and bonds undergoing dissolution or deposition of mineral mass, affecting geometrical characteristics of the system and thus determining the evolution of specific surface area and of bond cross-sectional area at the micro-scale, and of porosity at the macro-scale, which become key variables linking the micro-scale and macro-scale mechanisms. The resulting micro- to macro-scale model is validated against the available experimental evidence, consisting of a number of different chemo-mechanical experiments on calcarenite. The model is thus shown to provide a flexible framework for consistent interpretation of experimental loading paths, and can be readily extended to more complex materials or to incorporate additional effects.

In this study, we investigated the impact of thermal pressurization (TP) on temperature and pore pressure changes within the shear zone of a slipping fault under supercritical CO₂ injection. Injecting CO₂ into the subsurface increases pore pressure in the reservoir that may cause slip on a pre-existing fault leading to seismic events. As a weakening mechanism, TP of fault fluid during slip tends to reduce frictional resistance by increasing pore pressures along the fault shear zone. We employed a coupled thermo-hydro-mechanical finite element model to compare the response of fault shear zone during CO₂ injection with and without considering the TP effect. The CO₂ injection was simulated using a poroelasticity model. For the model with the TP effect, a simple constitutive law was implemented in the poroelasticity model to couple pore pressure changes with temperature rise due to frictional heating. The results indicated that, in general, TP can lead to a significant increase of pore pressure built up during CO₂ injection. The effects of hydraulic diffusivity and slip velocity on pore pressure and temperature changes were evaluated.

The East Japan Railway Company, which owns and operates major long distance and commuting lines in and north of Tokyo, is upgrading existing track embankments per the new aseismic guidelines so they will be resilient to withstand strong earthquakes in the future. Some of the embankment retrofit projects are installing double sheet pile walls with tie-wires or tie-rods that connect them to minimize the possibility of liquefaction of the embankments. The construction next to live railway tracks, especially those on embankments, requires extremely low vibration and allows for no ground settlement as part of special attention to railway safety. In addition, the work space is often quite limited due to steep slopes of the embankment, neighboring structures, overhead catenary lines, and/or overcrossing bridges with minimal distance from the tracks. The press-in piling method has been successfully adopted to drive sheet piles and tubular piles to meet these requirements for pile installation within a few meters of the rail company’s busy commuter lines.

Cyclic triaxial, direct simple shear, torsional shear, resonant column, and cyclic ring shear apparatuses have been used for evaluating cyclic shear strength and liquefaction resistance of cohesionless soils. In this study cyclic shear response of Fraser River sand is investigated using constant-volume cyclic ring shear tests. The effects of sample preparation method, vertical stress, number of loading cycles to liquefaction (N_L), cyclic stress ratio (CSR), and relative density (D_rc) on the liquefaction behavior of Fraser River sand are investigated. Fraser River sand specimens are prepared by different sample preparation methods and tested under stress-controlled, constant-volume, plane-strain shearing condition. The ring shear specimens are consolidated to vertical stresses of 100, and 200 kPa prior to the application of uniform, sinusoidal, shear stress cycles. The specimens are then subjected to cyclic shear stress ratios (CSR) of 0.08, 0.10, 0.12, 0.15 and 0.20. Cyclic shear strain and effective vertical stress respectively increase and decrease with increasing the number of loading cycles. Larger cyclic shear strains and greater reductions in effective vertical stress are also produced at higher CSR. It is found that saturated water-pluviated samples exhibit significantly higher cyclic shearing resistance compare to dry air-pluviated and saturated moist-tamped samples. Compared to cyclic direct simple shear tests, cyclic shearing resistance measured in ring shear experiments is higher due to the rigid boundaries of the specimen chamber which impose a perfect plane strain shearing condition.

Located in a seismic zone with a rugged topography, Lebanon is classified as highly vulnerable to earthquake and landslide hazards. According to Keefer (1984), even small magnitude earthquakes may trigger landslides leading to significant damages. Regional seismic hazard assessment for landslides has been done using methods based on the traditional infinite slope stability analysis following Newmark (1965). This approach provides a quick assessment of co-seismic landslides but has several disadvantages. In particular, the predefined failure surface leads to overestimated values of the critical accelerations of the slopes and underestimates the hazardous areas. Two newly proposed methods are implemented over a representative region of Lebanon with the use of the geographic information systems (GIS). Data including geological maps, high-resolution digital elevation models of the topography, site investigations and geotechnical data for the different geological units, earthquake peak ground acceleration maps, and a preliminary landslide inventory database are collected for the analysis. A co-seismic landslide hazard map for the country is then produced and the results are presented for a representative area. This hazard assessment represents the initial warning system that identifies high-risk sloping zones. Focus is particularly on densely populated urban areas where the landslide hazard greatly affects currently existing structures.

Most urban centers in India are prone to earthquakes and hence the assessment of seismic hazard and its secondary effects play a major role in mitigating the hazard for these cities. In India, the sub-standard quality of buildings and inadequate assessment of hazard pose a major risk in hazard mitigation. One of the best ways to tackle this issue is to identify seismic vulnerable regions in the country and take adequate measures for hazard mitigation. This paper addresses the issue of identifying the liquefaction susceptible areas in Mumbai City based on a probabilistic method. Mumbai, being a coastal city and situated on a deep soft soil deposit, the level of saturation and the soil conditions can worsen the seismic effects. The method adopted in this study uses an end-to-end probabilistic approach both for seismic hazard modeling and liquefaction potential evaluation. The use of probabilistic methods in liquefaction potential evaluation will help in quantifying the uncertainties involved in seismic hazard and soil parameters. The liquefaction return period curve and the factor of safety against liquefaction at various locations in Mumbai along with maps showing spatial variation of factor of safety against liquefaction are developed in the study.

In earthquake prone areas, computation of bearing capacity under seismic condition is very important for the safe design of foundations. In previous years, attempts were made to use pseudo-static approach and a very few investigators used pseudo-dynamic approach to compute the seismic bearing capacity. Using the limit equilibrium method, the values of bearing capacity factor for surface strip footings resting on cohesionless soil are obtained by considering simple planar rupture surfaces under seismic conditions. The seismic forces are computed using the modified pseudo-dynamic method in which dry cohesionless soil is assumed as visco-elastic medium subjected to harmonic base shaking. Width of the footing, seismic wave velocities and angular frequency of the input motion influence the value of seismic bearing capacity. Comparisons of the proposed method with available theories in the seismic case are also presented to highlight the advantages of the present method for the design of surface strip footings considering seismic waves.

This paper presents the seismic assessment of a central core embankment dam partially founded on relatively weak, low plastic fine-grained soils. Characterization of low plastic fine-grained soils, especially their cyclic and post-cyclic behavior was critical in assessing the seismic performance of the dam. A site investigation and laboratory testing program was undertaken to characterize the low plastic fine-grained soils and their behavior under the cyclic loading. An effective stress based constitutive model UBCSAND, developed at the University of British Columbia, Canada and implemented in the computer program FLAC, was shown to be able to capture the characteristic cyclic behavior observed in the laboratory cyclic direct simple shear tests. Seismic deformation analyses using the model showed that, although the low plastic fine grained soils will not behave like loose sand, it can still cause significant displacements due to accumulation of strains during cyclic loading.

Simple analytical solutions to predict the rotational displacements of seawall supporting cohesionless backfill under the combined action of earthquake forces, non-breaking wave force, hydrostatic and hydrodynamic forces for active earth pressure condition has been presented. The seismic forces are calculated by using the pseudo-static method. The excess pore pressures generated due to seismic shaking has been incorporated in the calculation of earth pressure in terms of excess pore pressure ratio. The amount of tilt has been calculated for both during and after the earthquake. A detailed parametric study has been conducted by varying parameters, such as height of non-breaking wave, depth of submergence of backfill, soil friction angle, backfill and wall inclinations and excess pore pressure ratio. It has been observed that, the rotational displacement of the wall is increasing by 48% as the ratio of height of non-breaking wave to the total height of seawall increases from 0.00 to 0.60. The results obtained in the present study are in good agreement when compared to the specific cases in available literature.

Ports are lifeline structures, which play an important role in the economic growth of any country. Hence these structures should necessarily be designed for earthquakes. Mormugao Port in the south west region of Goa State, which lies on the west coast of India is located at about 250 km from Koyna and 350 km from Latur which, in the past have experienced earthquakes of magnitude M_w=6.3 and M_w=6.2 respectively. In this paper, seismic ground response study is carried out for Mormugao Port of Goa State. Data of ten borelogs were obtained from the port site. The bedrock depth was found to vary from 10.50 to 16.50 m. The shear wave velocity (V_s) was evaluated using two established correlations developed between V_s and field SPT ‘N’. Earthquake time histories were developed for the port site using three methods: (i) generating synthetic accelerograms, (ii) generating artificial accelerograms, both by using SeismoArtif 2.1.0 software, and by (iii) matching the Indian seismic codal bedrock target spectra using SeismoMatch 2.1.0 software, by considering seed accelerograms of real earthquakes. One dimensional equivalent linear ground response analysis was carried out using DEEPSOIL v6.0 software using generated accelerograms. The influence of local soils on the bedrock motion (for 8 time histories) was represented in the form of surface acceleration time history, amplification spectra, response spectra, and ground motion parameters. The site at the Mormugao Port was found to be amplifying type with a maximum amplification (Fourier amplitude) of 12.69.

Rainfall-induced shallow landslides are one of the most significant hazards in mountain areas. In order to analyze and eventually predict the timing and locations of landslides triggering, we use a recent established USGS Hillslope FS2 model to simulate the hillslope hydrology and stability. Stresses, soil moisture, and soil suction are concurrently simulated by a coupled variably saturated flow and stress fields finite element model. The hydro-mechanical framework is applied to a hillslope in Macon County, North Carolina. Here, extensive failure of hillslopes often occurs after heavy tropical storms. In recent years, we conducted site monitoring of soil moisture and suction at different depths in some landslide-prone hillslopes. The objectives of the case study were: i) to simulate the stability conditions of the monitored slopes during hurricanes Frances and Ivan and ii) to identify a possible rainfall scenario for slope failure. The application involved the calibration of the hillslope hydro-mechanical properties by using the measured soil moisture and suction data. Results show that the hillslope was stable under the rainfall of hurricanes Frances and Ivan. However, it would fail if the intensity of the rainfall increased by a factor of 1.3.

The physicochemical characteristics of the recovered soil separated from disaster waste and tsunami sediment generated by the Great East Japan Earthquake can be significantly different from those of the non-affected soil because the recovered soil contains unavoidable contamination such as pieces of concrete and wood debris as well as sea water. This study investigated elemental release from the recovered soil with water percolation using a column leaching test in order to investigate changes in the elemental release characteristics of the recovered soil. The electrical conductivity (EC) in the leaching water was constant at the initial stage of testing and gradually decreased at the middle stage of the test. The main contributors to the high EC value were calcium and sulfate ions, and the effect of sea water on elemental release was limited. Copper and zinc concentrations were relatively high during the early part of the leaching test, and subsequently, the concentrations of these elements decreased. In contrast, low levels of fluoride, lead, and arsenic in the leaching water were detected initially; however, the concentrations dramatically increased with the decrease in calcium and sulfate concentrations. These results indicate that the characteristics of elemental release altered with water percolation.

This manuscript briefly introduces technical solutions for containment of the low-level radioactively contaminated soil and waste generated by the accident of Fukushima Daiichi nuclear power plants. Two technical concerns in designing and constructing the lining system are addressed and analyzed in the laboratory experiments. Firstly, hydraulic integrity of GCLs, which is installed as a barrier layer in the cover system, was investigated. The focus was placed on barrier performance of GCL overlap subjected to slippage and low overburden pressure, caused by differential settlement of waste layer. GCL overlap maintained its hydraulic integrity even against the overlap slippage up to 100 mm, although there were some variations in apparent hydraulic conductivity values, relating to overlap treatments. Secondly, a series of batch sorption tests was conducted to assess the effects of cations in the landfill leachate on the cesium sorption characteristics of mineral sorption layer, which is installed beneath the contaminated wastes and soils. Calcium and potassium ions in the leachate most significantly lowered the cesium sorption by sodium bentonite and decomposed granite soil, respectively.

The paper proposes eco-friendly adaptive techniques using locally available materials and industrial by-products. Used automobile tires, as an industrial by-product, were combined with palm fibers to construct reinforced dyke systems as a multiple protective measure. The tires used with a mangrove plantation inside can work together with mangroves to protect against impacts from such severe climate events as storm surges. The addition of the palm fibers plays a role in increasing dyke stability, particularly when mixed with cement and dyke soils.

This paper focuses on material properties of more than 400 soils recovered from disaster debris in Iwate Prefecture generated by the 2011 Great East Japan earthquake and tsunami. Analyses in this study verified that recovered materials basically have sufficient quality as geomaterial from the viewpoint of chemical and physical properties, being expected to be utilized in geotechnical applications though additional processes such as mixing of steel slag and crushed concrete affect material properties. Some results raised an experimental concern regarding applicability of existing test standards for assessment of recovered materials.

The Great East Japan Earthquake resulted in extensive damage and left a vast amount of debris. The debris from the disaster has been incinerated to reduce the volume. This study focused on the predicted future demand of land soil, for example, to use in post-disaster reconstruction works. In order to examine the availability to recycle and utilize the incineration bottom ash from the disaster debris, the material properties of the incineration bottom ash was evaluated by soil experiments. Features of incineration bottom ash recycled material were compared with general incineration bottom ash from F City. A modified CBR test (JIS A 1211) was adapted to evaluate the availability of using the material as subgrade and roadbed material. A constant pressure direct shear test was employed to assess the shear properties. The results show that the incineration bottom ash recycled material has equivalent shear properties with regard to physical composition compared to general incineration bottom ash. The study reports that there is a possibility for incineration bottom ash recycled material to be effectively utilized as a roadbed material and used as a soil material with varied strengths.

The 2011 off the Pacific coast of Tohoku earthquake has impacted Japan, and it made serious damage to nuclear power plant in Fukushima. At present, Japanese government and engineers proceed decommissioning of the power plant, and ensuring safety of workers is the most important matter especially in fuel debris retrieval. On these backgrounds, the authors focus on heavy bentonite based slurry for filling material of nuclear reactor. Heavy slurry is capable of shielding gamma ray and neutron beam from its high specific gravity and water content. The purpose of this research is to investigate and define the properties of heavy bentonite based slurry by soil mechanics experiment. That is, the research described in this paper is a proposal to use it for decommissioning of the Fukushima I nuclear power plant. For quantifying the radiation shielding properties, the authors measured the transmitted radiation dose through heavy slurry. The result shows the heavy slurry has definite radiation shielding properties. In conclusion, the heavy bentonite based slurry may be useful for radiation shielding, and save workers health in particular.

Pipelines are commonly buried underground to provide environmental stability, temperature insulation and mechanical protection. These pipelines are frequently subjected to earthquake induced upward displacements, which can cause significant social-economic loss to consumers and utility management. Further, high thermal and pressure of the conveying medium can induce differential stresses on the axial restrained pipe to result upward buckling of the pipeline that can disturb the serviceability conditions. The uplift resistance from soil cover protects the pipe against such unwanted movements, representing it as a vital design parameter, in that pipeline integrity under operating conditions relies on its value. The paper presents full-scale uplift results and finite-element parametric studies conducted to investigate the effects of dimensionless cover heights (soil cover height to diameter ratio), soil relative density and moisture content on the peak uplift resistance of pipes. The results showed that the available analytical models could predict realistic peak uplift resistance for pipes buried at shallower depths, however, they can substantially under-predict the pipe loads/uplift resistance especially when buried at deeper embedded depths and non-dry soil conditions. The results of the current study are useful for pipe designs against earthquakes and/or severe operating conditions induced uplift displacements in sandy soils.

In this study a geo-environmental approach was used for the restoration of the farmed land that was damaged by salinity, due to tsunami water in the pacific coast of Tohoku region in Japan. In order to confirm the effect of the organic fertilizer with salt-tolerance bacteria, laboratory tests of the tsunami sediments and the soils separated from disaster wastes were performed. The organic fertilizer can be easily increased by mixing rice bran, oil cakes, grinds of fish bones and water. Electric conductivity, EC, of the tsunami sediments mixed with the organic fertilizer was measured continuously. The value of EC decreases with increase in curing period and becomes almost a half after one month. The potting cultivation test for rice plants was conducted. The soils separated from disaster wastes also contain salt from seawater. The organic fertilizer was also mixed with the separated soils and its applicability was confirmed by laboratory tests.

This paper presents a two-field semi-Lagrangian reproducing kernel particle method for landslide simulations. The method combines advantages of Eulerian and Lagrangian formulations in that state variables follow material points while the approximation functions are updated in the current configuration to allow extreme deformation and material separation. The Biot theory is employed to describe poromechanics of geomaterials. A Drucker-Prager model with damage is adopted to represent constitutive model of solid phase of porous media. In addition, a variationally consistent integration (VCI) scheme is employed in the two-field semi-Lagrangian formulation to enhance solution accuracy. The proposed method is verified with several numerical examples and its applicability of simulating landslide events is validated with an experimental result.

Himalaya is an active mountain belt where high tectonic activities, since its formation, have been one of the major inherent and internal factors for some of the major landslide hazards. In this study, a watershed named as Patalganga located in NW Himalayan region of Garhwal between longitude 79°29′15″ E-79°29′30″ E and latitude 30°29′25″ N-30°29′15″ N has been selected for morphometric analysis of certain parameters relevant to landslide hazard. The watershed is highly vulnerable to such phenomena because of its fragile geoenvironmental setting and a large number of landslides of different shapes and sizes have already been reported within the basin. These landslide activities have been correlated with the morphometric parameters through calculation of their areal, linear, relief and hydrological characteristics in GIS platform. Some of these morphometric indices have been capable of identifying the landslide signatures and even predict the future landslide activities. Slope length gradient index is one of the tools which has been taken as a major point of discussion in the paper which highlights the role of knickpoints in the probability of developing landslides and even the landslide dams on the river. Out of fourteen numbers of knickpoints identified, ten were found to have direct correlation with the landslide activity which has been verified from the landslide inventory maps of the area.

One of the major driving forces behind the recent popularization of spatial information is the increasing availability of spatial data from governmental and commercial sources. A large number of spatial data depots, digital geolibraries and spatial data warehouses have been developed or are under development in all sectors of modern society. The Municipality of Abu Dhabi City (ADM) recently developed a GIS portal that works as a focal point of information and spatial data-related assets. An important component of this GIS portal is the geohazard information management system (GHIMS), a spatial database system that stores and manages geotechnical, hydrogeological and geophysical data along with interpreted geology, lithology and geohazard risk maps. This paper discusses the approach towards the design and implementation of a spatial database that forms the backbone the GHIMS. All relevant data and information were initially stored in an ESRI geodatabase using a feature based model to maintain consistency and conformity to projection and resolution standards. Configuration controls, attribute domains and topology elements were applied to appropriate feature classes to ensure and maintain data quality standards. Key factors influencing the geodatabase design were data volume, data format and extent of analyses. The geodatabase has feature datasets and raster catalogs that provide geotechnical, geological, and hydrogeological information, and damages related to buildings and infrastructure. The geodatabase also stores intermediary information necessary for generation of geohazard risk maps, such as reclassified rasters, distribution maps, model-builder toolboxes, and tools. The geodatabase was then migrated to the Oracle Spatial environment. Key assumptions, constraints, and decisions taken during the geodatabase design are also discussed along with factors that may affect the database performance, extendibility, and maintainability.

The Municipality of Abu Dhabi City (ADM) routinely commissions and manages projects where large volumes of data from site investigations are archived by internal and external users. The data includes legacy information from site investigation projects such as borehole logs, interpretive reports, cross sections, and field and lab test data. The information was either in image or paper format. The extensive volume and the format of the data made it impossible to query for specific needs. Also, due to its large quantity, storage and filing systems were cumbersome for users with potential for documents to be misplaced. The Spatial Data Division within the Abu Dhabi Municipality developed the geotechnical information management system (GIMS) as a comprehensive data storage and management solution that enables easy access to all geotechnical data. The geotechnical information from the legacy data were digitized and effectively archived so that it could be made accessible internally and externally. Information relating to the subsurface from 21,257 hardcopy borehole logs and reports were extracted and stored in a gINT database which is compatible with the Association of Geotechnical and Geoenvironmental Specialists (AGS) 3.1 data interchange standard.. The GIMS database consists of 93 tables; however for the most commonly used field and laboratory tests, a subset database consisting of 30 tables to address specific geotechnical data submittal requirements was developed as well. Strict procedures and standards for geotechnical data submittal applicable to contractors and consultants were also defined to ensure streamlined updates to the database. The GIMS was also designed to interact with other software such as existing GIS and civil design software. A custom geotechnical web map application (WMA) was developed to handle dynamic data delivery to the end user through the web. This GIS integration enables access to existing geotechnical data via the internet or the ADM’s intranet. This paper discusses in detail the design decisions, various aspects of implementation and the challenges faced during development of the entire GIMS application.

The objective of this paper is to examine the influence of hybrid geosynthetic layers in dissipating pore water pressures in geogrid reinforced soil walls with marginal backfill subjected to rainfall. In this regard, numerical modelling was carried-out using a finite-element based software SEEP/W by subjecting the soil wall to different rainfall intensities, ranging from 10 mm/hr to 80 mm/hr. For selected sections, static global stability of the soil wall with and without hybrid geosynthetic layers was carried-out using SLOPE/W. The number of hybrid geosynthetic layers was varied to arrive at the optimum number of layers needed to maintain stability against different intensities of rainfall simulated, and the results were compared with equivalent number of conventional sand drainage layers. The results indicated that, the hybrid geosynthetic layers placed at bottom half were more effective in reducing the pore water pressures developed during rainfall, and in improving the stability of the reinforced wall section than identical number of sand layers.

Sinkhole is a hazardous geological phenomenon which in recent years has occurred with an alarmingly increased frequency around the world. Although the conceptual nature of the involved key mechanisms of formation of the sinkhole is well-known and is believed to be related to the interaction between the underlying limestone rock layer and the groundwater subsequently leading to the accumulated deformation in the soil overlaying the weakened rocks, there has not been an adequate amount of geomechanical research devoted to the study of sinkholes in a quantitative manner. This paper presents some of the preliminary results of an ongoing research aimed to explore a geo-mechanical modelling approach and to understand the behavior of geo-materials around sinkholes. The finite difference program, FLAC, is used to model the behavior of geo-materials involved and simulate the deformation and stress characteristics of sinkholes. A parametric study is conducted to examine the results with different sizes of cavity, overburden thickness and pressure. The potential scenario of water drawdown is also examined. The results demonstrate some key characteristics of sinkhole subsidence and the feasibility of a geomechanical approach manifested in numerical modelling to improve the understanding of the process of sinkhole development.

Lightning rods are usually employed to reduce lightning hazards in facilities such as power distribution lines through transmitting the lightning to the ground. The high electrical conductivity of the surrounding soils is the prerequisite for the effectiveness of the lightning rod. In general, the electrical conductivity increases with increasing the degree of saturation. Therefore, the surrounding soils with a low moisture content may possess a relatively low electrical conductivity, which increase the lightning hazards. It is thus desirable to main a high moisture content in soils surrounding the lightning rod. The water flow in the soils induced by external electrical field is usually referred as electro-osmosis flow, which has been widely used in ground remediation in geotechnical engineering. Based this physical phenomenon, an external anode method is proposed in this paper to maintain the high moisture content around the grounding rod by inserting an anode around the grounding rod. The feasibility analysis of the proposed external electric anode method was carried out through numerical simulations. The physical phenomenon underlying the proposed method was a typical coupled electro-saturated-unsaturated water flow process in porous media. In order to model this complex coupled process, a multi-physical framework is proposed to solve this problem numerically. The coupled electro-saturated-unsaturated water flow is decoupled by introducing a series of physical relationships which could be directly obtained through specific geotechnical experiments. At last, two comprehensive parametric studies were conducted to preliminarily assess the feasibility of the proposed method. Results of the case studies reveal that the external anode method has the potential to reduce the lightning hazards.

The term water holding capacity (WHC) has long been used to help researchers determine how soils respond to typical wetting under rainfall. However the term WHC is insufficient as a measurement to describe how soil responds to flooding events. This paper aims present a novel method for WHC testing that also incorporates the volume change, shear strength, erosional resistance and hydraulic conductivity of the soil under saturated conditions. The qualitative combination of these parameters will be used to outline a soil’s ability to withstand flooding, or its ‘flood holding capacity’. Data from recent testing that uses both compost and recycled minerals from the treatment of drinking water to amend soil to improve its ‘flood holding capacity’ (FHC) is presented in this paper to highlight the shortcomings of using WHC alone. At this stage of research the idea of flood holding capacity is only conceptual, however the premise of flood holding capacity is examined using this experimental data.

At the present time, it is very common in practice (industry as well as in research) to utilize Mohr-Coulomb to simulate the soil behaviour in the application of soil-structure interaction problems. The model is often chosen considering its simplicity, ease of use, reasonable computational time and the high level of understanding among the engineers. However, the linear elastic-perfectly plastic Mohr-Coulomb model is unable to predict the softening behaviour of material and hence to predict the pipe load accurately when subjected to large soil movements such as from landslides or earthquakes. A user defined modified Mohr-Coulomb model is developed to capture the strain softening behaviour of soil and to simulate the pipeline response subjected to large ground deformation. The softening behaviour of the model has been calibrated on the basis of direct shear test data, and triaxial test data have been used for calibrating the yielding and flow characteristics of the model. The calibrated model has been applied to simulate the response of HDPE pipeline undergoing different ground displacements. Finally, the model response was used to develop a strain demand model for buried pipelines facilitating the risk assessments.

In this work, it has been verified the ability of a computational tool known as artificial neural networks to predict landslides triggered by rains in mountainous areas. The neuronal model was trained and verified for a tropical mountainous location in the city of Medellin, Colombia. The construction of the database, composed by 2054 samples, consisted in obtaining nine representative slopes and twenty typical rains of the study site, characterized by their duration and return period. There have been combined data of nine slopes and twenty rainfalls, there by obtaining the fluid pressure profile in a finite element code, in order to get the safety in each of the analyzed cases. To obtain shear strength values for the simulations, the parabolic envelope proposed by Lade (2010) was used. Thus, the input data to the neural network are the slope and the precipitation and the output is the safety factor. It has been verified the ability of the neural networks to learn specific information of the studied problem and give an answer, with minimum error, for any other condition, generalizing the problem and allowing the application of the tool in a location with similar conditions.

The demand of infrastructure investment in the world has led to invest high financial values to solve problems related to population growth. The rehabilitation and expansion of civil infrastructure are required to serve the growing needs of society and is directly limited by the availability of competent soils upon which construction can occur. Parallel to this, environmental degradation of ecosystems is occurring in an exponential level, thus contributing to problems such as pollution of groundwater, soil and air. From the socio-economic point of view, the infrastructure activity is shown to be divergent. Even though, on the one hand, represent development, the benefit ultimately achieve environmental problems and may cause health risks for people and for the environment. Most soil improvement techniques, which are used worldwide, involve the addition of mechanical energy and/or synthetic material, both of which have substantial energy cost associated with their production, however, the bio-cementation technique has as order to improve the mechanical properties in a sustainable way. Bio-cementation is the formation of particulate material attached to the soil by microorganisms. The various microbiological processes have the potential to modify the behavior of the soil. Many bacteria such as the species: Bacillus, Sporosarcina, Sporolactobacillus, Clostridium and Desulfotomaculum have potential for biological cementation. Nanoparticles are usually coated in order to enable obtaining properties of higher performance, however, it appears as a potential using nano-calcium to increase the soil resistance in bio-cementation process.

This investigation was conducted to evaluate index properties of clay soils in presence of nanoparticles, which applies to assessing both risks (containment system integrity and environmental impacts) and benefits (potential use in geotechnical applications). Atterberg limits, swell index, pH, total dissolved solids (TDS), and electrical conductivity of soil-nanoparticle mixtures were determined. Tests were conducted on CL soil, CH soil, and bentonite. Metallic nanoparticles (SiO₂ and Ag) were used in the analysis. Nanoparticles were added to the test soils at mixture ratios ranging from 0.1% to 1.0% (by weight). The results of the test program indicated that the index properties measured generally were affected by presence of nanoparticles. Atterberg limits for soil-nanoparticle mixtures typically were lower compared to data for baseline soils. Swell tests generally were not sensitive to nanoparticle addition. The SiO₂ had relatively high dissolution in DI water as indicated by the measured high TDS and electrical conductivity, whereas the Ag nanoparticles had minimal dissolution. The observed increases in TDS and conductivity in the soil-nanoparticle mixtures likely resulted from pH- and ligand-driven dissolution of the SiO₂ and Ag nanoparticles, respectively. The dissolution processes were time-dependent varying with soil and nanoparticle type.

The main goal of this work is to investigate the effect of addition of nano-clay material on the improvement of strength and swelling potential of an expansive clayey soil. The geotechnical properties of a selected expansive clayey soil obtained from Irbid city were determined for soil classification purposes. Free swelling and unconfined compressive strength UCS were conducted on soil samples with different percentages of nano-clay added at about 0.1% to 3.0% by weight and compared to samples free of nano-clay material. The results showed that the addition of nano-clay may increase the strength of expansive soil at low doses, however, swelling potential decreased with the addition of nano-clay.

The development of new remediation techniques is needed due to the great diversity of contaminated areas. Nanomaterials, especially zero valent nanoiron particles, have been most frequently used because of their higher reactivity, lower toxicity, and lower cost than other metallic nanoparticles. Even though the nanoparticles’ size is smaller than soil pores, clogging may happen over time, reducing the permeability of the soil. When residual clay soil is used, the suitable zero valent nanoiron concentration that must be used for remediation is unknown. This concentration can interfere with the permeability of and the reactivity with the contaminant. Thus, the objective of this work was to evaluate the hydraulic conductivity in residual clay soil for different nanoiron concentrations (1 g/L, 4 g/L, 7 g/L, and 10 g/L). Undeformed specimens was molded with a 5-cm diameter and 5-cm height. Percolation tests were performed using a column apparatus while observing the variation in conductivity over time. The results showed that the concentrations of 1 and 4 g/L do not affect the soil conductivity. However, beyond these values, there is a change to the natural values of the conductivity, affecting the process of the migration of zero valent nanoiron in the soil.

Lead (Pb²⁺) contamination in soils leads to its leaching and release which in turn, poses significant environmental and health risks. In lieu of this, a number of studies are available for solidification and stabilization as a remediation technique for brown fields typically contaminated with Pb²⁺. In this study, the performance of two soils in retaining Pb²⁺ has been evaluated. Two tropical soils were selected and amended with nano calcium silicate (potential stabilizing material) in small percentages to enhance the Pb²⁺ fixation. Batch adsorption studies, leaching tests and kinetic studies were conducted. The experimental data was then used to plot adsorption isotherms. Langmuir isotherm was found to be more suitable than Freundlich isotherm for both soil mixtures. Kinetic data was fitted on selected four models viz., pseudo first order, second order, Elovich and intra particle diffusion. Correlation coefficients obtained by all models fitted well with the following ranking: Elovich > Intraparticle diffusion > Pseudo second order > Pseudo first order. Qualitative measurements were also made using SEM and EDS. The leachable heavy metal concentrations were reduced following soil-nano calcium silicate treatment to concentrations lower than the TCLP standard regulatory threshold of < 5 mg L⁻¹ for Pb²⁺ even after a curing period of more than 90 days. Results suggest that the soil nano-metallic Ca/CaO mixture is suitable for use in immobilization of Pb²⁺ contaminated soil under normal moisture conditions.

Polymers are often used to modify base asphalt binders to withstand heavy traffic loads and extreme weather conditions. However, polymer-modified asphalts are about 75% more expensive than the base binders. On the other hand, nanoclays are naturally abundant, environmentally friendly, and very inexpensive. Nanoclays can potentially be an alternative of highly expensive polymers to modify asphalt binders. To this end, this study evaluated moisture resistance (stripping) of nanoclays-modified binders through the surface free energy (SFE) technique. A commonly used performance grade (PG 64-22) binder modified with different dosages of four types of commercial nanoclays was evaluated in the laboratory. The adhesive energies, an indicator of bond strength, of nanoclay-modified binders and five different aggregates were also evaluated. It was observed that the work of cohesion increased when the asphalt binder was modified with nanoclays. A small amount (about 4%) nanoclays seemed to be effective in maintaining good wetting ability with different aggregates. Also, smaller nanoclays were found to be more compatible than relatively larger nanoclays.

In recent years, there has been a great interest in using eco-friendly polymers in construction of geo-infrastructures to help in reducing their carbon footprint and enhancing their sustainability. Green polymers are one of these materials. Green polymers are polymers derived from plants that consist of starches, sugars, and cellulose. One of the green polymers that have received attention is polylactic acid (PLA). PLA is a hydrophobic, aliphatic polyester that can be extracted from most commonly from corn starches. This paper explores the use of PLA and PLA nano-composites as an alternative polymer to fabricate geosynthetics. To this end, PLA nano-composite materials were prepared using different carbon nanofibers contents. The mechanical properties of the produced nanocomposites samples were examined and compared to a geogrid material typically used in reinforcement of geomaterials in highway embankments and pavement structures. The results indicated that the carbon nanofibers enhanced the elastic modulus of PLA, but reduced its failure strain. Although the PLA carbon nanocomposites had higher tensile modulus than the geogrid materials tested in this study, they had lower tensile strength and strain. It is recommended that plasticizers used with the PLA nanocomposites to enhance their ductility.

Reactive geomembranes and geotextiles are an innovative approach to control the migration of contaminants in geotechnical applications. Within a joint research project in cooperation with a medium-sized enterprise, the preparation and characterization of “reactive” geomembranes and geotextiles modified by the addition of zero-valent metal nanoparticles was performed. Zero-valent iron (ZVI) nanoparticles were added to polyethylene or to the fillings of geo-containers or geosynthetic clay liners. These geosynthetic products consist of mixtures of sand with clay or bentonite, typically embedded in geotextile nonwovens or geomats. The permeability of these geo-containers can be adjusted by the ratio of clay or bentonite to sand. ZVI nanoparticles were also added as reactive material to geomembranes made of polyethylene with additives like the antioxidant Irganox 1010 or glycerin. These additives prohibit oxidation of the nanoparticle and act as hydrogen donor in the dechlorination of chlorinated hydrocarbons. Contaminates such as chlorinated hydrocarbons and toxic heavy metal compounds are either decomposed or converted to less toxic species (e.g. Cr-(VI) reduction to Cr-(III)). The paper reports the first experimental results from manufacturing of the reactive geomembrane model materials and characterization of the products with microscopic techniques. First breakthrough measurements of the ZVI modified geomembrane compared to a reference sample are presented.

For reducing damage of rock fall, it is important to estimate the route, leap height and velocity of the rock. Although research about estimation of falling motion of rocks are actively conducted, there are still unsolved issues, since rock fall is a complex phenomenon affected by position, size, or shape of rocks and angle of slope. This paper proposes a method of rock fall simulation using a 3D model of rock and slope reconstructed by merging multiple-view images. The proposed method requires only a mobile camera to generate a 3D model, so that more practical rock fall simulation can be realized. In addition, reconstructing textured 3D model makes inspectors visually confirm how the rock falls on the slope. Due to the difficulty capturing multiple images of both of rocks and a slope at a same time, rocks and a slope are individually captured, and then, they are merged in the post process. There are two problems to be solved for merging them accurately. One is the significant difference in their spatial resolution; the other is the difference in the appearance caused by perspective projection. We conduct an experiments using multiple images of rocks and slopes captured at actual landslide site.

Planning and designing countermeasures for a specific landslide require geotechnical and geological investigations of the landslide area. In particular, assessment of the extent of unstable zones and/or sliding surfaces of the landslide is essential for designing countermeasures. While borehole logging is the effective way to identify the sliding surface and shear zones, installation of the drilling systems can be prohibiting, depending on the accessibility and budgetary conditions. Past research, on the other hand, suggests that the surficial displacements may be utilized to estimate the shear zones. This paper presents the predictive analysis of the subsurface shear zone of the landslide along the highway passing the north mountain range of Malaysia. A marked failure occurred in 2003, followed by gradual continuous movements that have been monitored by 17 reflective prisms and the two total stations. No bore logging has been performed, and therefore, sliding surfaces are not well known. For the purpose of estimating the depth profile of the sliding surface, directions and magnitudes of the displacement vectors have been examined and subsequently numerical analysis of the displacement vectors was performed. The monitored displacements were reproduced by stepwise strength reduction, which yielded a band of cumulative shear failure zone that may represent the potential sliding surface.

Stability analysis of the two abutment slopes of a railway bridge proposed at about 359 m above the ground level, crossing a river and connecting two huge hillocks in the Himalayas, India, is presented in this paper. The rock slopes are composed of highly jointed rock mass and the joint spacing and orientation are varying along the elevation of the slopes. Geological mapping was carried out to characterise discontinuities present along different elevations of the slopes. Rock mass present along both the slopes was classified using rock mass rating (RMR) and geological strength index (GSI). Strength and deformation properties of intact rock and rock mass were estimated using different laboratory tests, in-situ tests and empirical relations. Since, the slope sections support bridge piers, bearing capacity was estimated with the help of in-situ tests and various empirical and analytical relations. Global stability and stability of individual sections of slopes were checked using different methods i.e. finite element, stereographic projections and wedge failure analysis. It was observed that slopes were globally stable however there was a possibility of wedge failure at some slope sections. Suitable rock anchors were installed at unstable slope sections. In addition to the stability analysis of the slopes, various challenges encountered during excavation and stabilisation of the suggested slope profile such as transportation of rock mass debris without allowing it to fall into the river and slope monitoring is discussed.

Extensive area of Japan is subjected to threats of potential landslides as roughly 70 percent of Japan consists of a steep mountainous terrain and moreover numerous artificial hill slopes are developed in residential areas. While various types of structural counter measures have been developed and successfully implemented in Japan, significant numbers of areas remain unprotected. Hence, non-structural measures, such as hazard maps and early warning systems, are required to minimize risks. One of the key technologies of the early warning system is the automatic detection system for landslides. In this research, we are developing an automatic detection system for landslides using ZigBee wireless communication technology. A general ZigBee-compliant platform made by Hitachi Co. Ltd. was customized and used in the constructing the wireless landslide detection system. The developed system monitors various environmental data, such as 3-axes acceleration, temperature, humidity, and illumination intensity. It was verified that all measured parameters except humidity were measured properly at an actual slope site with the proposed system.

The McCook Reservoir project is a below-grade reservoir to temporarily store combined sanitary overflow (CSO) water from the city of Chicago and surrounding communities. CSO is stored until it can be treated and then discharged into the Chicago sanitary and ship canal (CSSC). The reservoir is being excavated through approximately 15.2 m (50 ft) of soil and 76.2 m (250 ft) of rock, requiring the installation of earthen retaining walls and rock support measures for the near vertical rock wall to achieve the design depths and geometries. In addition, in order to minimize groundwater infiltration and CSO exfiltration, a perimeter cutoff wall and grout curtain have been installed. Due to the project proximity to adjacent roadways, railways, and waterways as well as for onsite project safety, a potential failure modes analysis was performed on the various project features and a surveillance and monitoring plan was developed to monitor for those failure modes that were deemed credible. This monitoring program consists of a series of piezometers, inclinometers, time domain reflectometry, extensometers, crack meters, survey methods, and visual monitoring. An automated data acquisition system (ADAS) is also installed that permits near-real time access to automated instrumentation data. The purpose of this paper is to discuss the lessons learned regarding design and installation considerations for the design, installation, data management, interpretation, and evaluation of the instrumentation.

A section of oil pipeline near Fairbanks, Alaska is experiencing hillslope movement. While the pipeline’s support system was designed to handle large movements, the slope movements are starting to exceed the anticipated design requirements. The pipeline was constructed on low angle permafrost slopes composed of Fairbanks silt. The silt occurs in three relatively distinct layers; an upper active layer, followed by an ice-rich silt layer overlying a non-ice rich silt layer. Based on inclinometer data, the slope movement is occurring near the ice-rich layer/non-ice layer interface at a rate of 4.5 cm/year. A traditional slope stability back analysis indicates that for slope instability to develop, the ice-rich layer (assumed the weakest) would require the layer’s friction angle to be in the range of about three degrees; much lower than traditional strength values would suggest. While some small underground gold mine shafts are located about 100 meter from the base of the slope movement, it is speculated that an additional factor causing slope creep is the syngenetic formation of the permafrost, which formed in successive frozen layers during freezing. Recent research has also suggest the possibility of cold weather neoformation of smectic clays developing that could assist in slope creep.

To stabilize slopes and support excavations, soil nailing is known for its low cost, high safety, workability and remarkable performance. Combinatorial anchorages are more effective, and where high safety factors are required, prestressed cables are used with concrete blocks, in-situ concrete piles or double steel profile. Researches on parameters affecting safety factor, stress, settlement and displacement many; however, studies on the effects of additional excavation on excavation walls or methods and mechanisms that preserve the additional depth without compromising the whole wall stability are few. This paper investigates the effects of 7m additional excavation on 23m-deep excavation walls of the twin towers project in Shahr-e kord, Iran, retained by soil nailing. To do this, use was made of 2D-FEM and anchorage method with in-situ concrete piles, and the results were validated through comparing the calculated and measured wall displacements. Effects of seven key design factors (pile diameter, horizontal spacing, embedded depth, and anchor angle, prestressing force, bonded/unbonded length of the piles or anchors) have been discussed based on the results of FEM which is quite an efficient method for settlement predictions. Finally, a number of design charts have been prepared for in-situ concrete pile anchorage used in additional excavations.

A recent advancement of technology led to the development of wireless remote sensing devices that can overcome many limitations of some widely used conventional monitoring technologies. This paper is limited to describing the framework of the wireless sensor network (WSN) system that allows wireless communication between the sensors and the remote computer and hence, understanding the motional behavior of the sensors during rock fall. The results from two controlled experiments and a series of free fall experiments where fall was led by rolling and sliding, are presented. Sensor tags were used to indicate slope movement or change in slope behavior leading to failure. A WSN system was developed and installed on a small-scale slope system simulating the free-fall of rock mass. Our experimental results describe different rock fall patterns which facilitate subsequent establishment of failure thresholds. Results obtained from these laboratory experiments will improve potential slope failure prediction and alleviate its hazardous risk through the development of a warning system. Being accurately informed of impending failure is in itself a great achievement; knowing the failure type helps people envision the extent of damage the failure would cause. This advancement increases the safety of lives and properties.

This paper illustrates techniques for assessing the location of past and future landslides using LiDAR. More importantly, this paper will use LiDAR to identify areas susceptible to large landslides which is important for hazard mapping, safe zoning, and public safety. The assessment techniques will be illustrated using the 2014 SR-530 landslide near Oso, Washington. This major and tragic landslide exhibited some important aspects of geo-mechanical behavior that will be discussed and how LiDAR and geotechnical reconnaissance can be used to avoid a future tragedy.

In this study electrical resistivity tomography (ERT) was conducted to assess any anomalous seepage through an earth dam. Two ERT profiles on earth dam crests were recorded using AGI supersting R1/IP equipment - a total of 28 electrodes, spaced at one meter, were used in the resistivity testing - and then analyzed with EarthImager 2D. In addition, dynamic cone penetration (DCP) testing was used to identify various soil strata through the embankment of the earth dam. Correlations (qualitative and quantitative) were established between electrical resistivity and DCP rate which provided useful information for integrating electrical resistivity and geotechnical properties. The DCP testing was conducted in accordance with the ASTM D 6951. Shelby tube specimens were collected for laboratory testing (i.e., shear strength, consolidation, permeability, and soil classification). ERT analysis revealed the presence of clay layers and a saturated zone that could be a seepage zone. Findings showed that higher DCP value was associated with low resistivity value.

Life cycle assessments of recycled material use in roadways are currently not well understood or well documented. The Recycled Materials Resource Center’s (RMRC) research is aimed at quantitatively determining the environmental and economic benefits of using recycled material in road construction. Two case studies were performed to analyze the impacts of incorporating recycled material in the reconstruction of two major roadways using life cycle assessment (LCA) and life cycle cost analysis (LCCA) tools. Results from both roads show that the use of recycled materials reduces energy and water consumption, greenhouse gas emissions, and cost. Because typical roadway construction projects do not separately track the extensive use of recycled materials, the RMRC was unable to utilize the LCA and LCCA technology in the first roadway’s analysis without making significant assumptions for the inputs. To clarify and verify some of these assumptions, the second roadway project was undertaken. This second case study is being studied to determine a better methodology for data collection with fewer assumptions, in addition to assessing the benefits of recycled material use. The methodology for data collection and analysis developed through the second project can be used to conduct LCAs and LCCA for future highway construction projects with greater confidence.

Thal Doab Aquifer (TDA) lies in Indus Basin has experienced rapid growth of population, livestock and agricultural activities because of easy availability of surface and groundwater. The alarming growth rates of these three interrelated landuse activities are the source of pollution of TDA from non point sources (NPS). So for the managerial purposes an efficient approach for the assessment of groundwater aquifer sensitivity, the DRASTIC model in geographic information system (GIS) environment was applied. GIS layers were developed for each of the DRASTIC parameters and combined into natural sensitivity coverage. The resultant natural vulnerability values were grouped into four categories: low to moderate-indicating that the groundwater aquifer is very well protected and risk of contamination from NPS is very low; high-the groundwater aquifer is much more susceptible to contamination due to several hydrologic conditions; and very high-all hydrologic parameters are conducive to the rapid transport of contamination to the groundwater aquifer. Results indicate that, most part of the study area falls under high to very high vulnerability zone, eastern part 17.2% is under very high vulnerability zone, while a small portion of about 15.6% is under low vulnerability zone at north and northwestern parts.

In this study, focus is placed on ground improvement in seismic regions, as a geotechnical application of major economic and environmental consequence. To this end, a pilot framework is developed for assessment of related cost and carbon emissions. For a representative residential structure built on potentially liquefiable ground, three options are considered. The first option is to implement a ground modification countermeasure before constructing the structure. The other options include repair of damage, primarily by re-levelling the structure if the earthquake occurs. For the developer/stakeholder, the initial as well as potential post-earthquake cost and carbon emissions are factors of interest. The a priori ground modification considered for this study is vibro stone columns, and the technique for post-earthquake re-levelling of the residence is compaction grouting. Carbon emissions are computed via process-based life-cycle-assessment (P-LCA). The analysis framework is presented along with the underlying calculation procedures. Potential benefits and shortcomings in terms of cost and carbon emission are contrasted, highlighting significance to the process of decision support.

The Riverwalk is located in the middle of downtown Chicago and extends nearly 2,800 ft. along the main branch of the Chicago River between State Street and Lake Street. The project consists of six themed “rooms” connected by canopied “underbridges” beneath the existing bascule bridges to provide a continuous path. The goal of the project was to provide an area for Chicago’s residents, workers, and visitors to connect with nature in the heart of the city, which led to a wide-ranging theme of sustainability throughout all aspects of the design. This paper presents a case study of the considerations and challenges associated with the design and construction of a sustainable public project in a complex urban environment.

Various sustainability rating systems have been developed to provide an objective framework for assessing infrastructure projects. Examples include civil engineering environmental quality assessment and award scheme (CEEQUAL), Greenroads, Envision, infrastructure voluntary evaluation sustainability tool (INVEST), and infrastructure sustainability (IS). These rating systems aim to help the construction industry identify and quantify sustainable approaches that are beneficial to infrastructure projects. Most of these infrastructure rating systems have their origins in the rating systems developed for evaluating commercial buildings, such as building research establishment environmental assessment methodology (BREEAM), leadership in energy and environmental design (LEED), green globes, and Energy Star, which poses a few challenges when these types of tools are applied to broader infrastructure projects. Of most significance is the lack of a financial sustainability metric within the tools. This is understandable: buildings generally have a well-defined and relatively short service life for revenue generation, clear redevelopment options to perpetuate the real property value, and few long-term liabilities or legacy issues (e.g., pollution potential). However, other infrastructure projects have much longer service lives and are even expected to remain viable over an indefinite post-service period long after revenue generation has ended. This paper presents a review of sustainability metrics used by various infrastructure rating systems and compare their advantages and disadvantages. Thereafter, the paper discusses the need to engage and encourage decision makers to invest in more sustainable approaches for developing large infrastructure projects with very long term service and post-service lives by including a financial metric to existing rating systems. Finally the paper discusses a few financing options which could help the construction industry transition to more sustainable design approaches while simultaneously protecting their return on investment.

The construction of underground subway facilities will introduce a barrier to the natural groundwater flow due to the presence of permanent structures buried in the ground. This will create a damming effect and cause a rise in the groundwater level in the vicinity of the subway structures. This paper presents an equilibration system that was adopted for the second avenue subway project in Manhattan, New York City to deal with the groundwater accumulation problem. The equilibration system consisted of a network of pipes and manholes that collects water built up on the upstream side of an underground structure to be transferred across and discharged into the ground on the downstream side. The design of the equilibration system was based on the principle of hydraulic flow under a potential energy difference. The system was designed to be self-sustaining and maintenance free.

Drilled shafts can be designed in various ways depending on the assumptions involved. However, the difference between the different design methods manifests significantly in terms of environmental impacts. In order to study this aspect systematically, drilled shafts are designed using eight different design methods for a homogeneous and a layered sand profile. The environmental impacts of the different designs are evaluated by life cycle assessment (LCA). Parametric studies are performed to study the impact of soil properties on the environmental impacts.

A procedure is developed to minimize cost and CO₂ emissions for the design of reinforced concrete drilled shafts subjected to axial loading, satisfying geotechnical limit states and using a Big Bang-Big Crunch (BB-BC) algorithm. The objectives of this research are to develop low-cost and low-CO₂ emission designs of drilled shafts and to compare low-cost and low-CO₂ emission designs. Cost is based on materials and labor required for the construction of drilled shafts. The CO₂ emissions are associated with the extraction and transportation of raw materials; processing, manufacturing, and fabrication of products; and the emissions of equipment involved in the construction process. The cost and CO₂ objective functions are subjected to soil bearing and displacement limits. A design example is presented to compare low-cost and low-CO₂ emission designs. Results are presented that demonstrate the effects of different magnitudes of applied axial loads, soil properties, factors of safety, and allowable settlements on low-cost and low-CO₂ emission designs.

The use of recycled materials in highway construction has the potential to achieve significant benefits affecting the triple-bottom line (environment, prosperity and society). Although state departments of transportation (DOTs) have been in the forefront of introducing recycled materials, they have not been able to clearly convey the benefits in a quantitative and transparent manner using easily understood metrics. What is lacking is direct information on sustainability assessment characteristics, i.e. greenhouse gas emissions, energy and water consumption, and waste generation. To determine the benefits of using recycled materials for DOTs, the Recycled Materials Resource Center (RMRC) is undertaking a project with the objective of providing a tool to quantitatively analyze and report the environmental and life cycle benefits of using recycled materials in highway construction. Subsequently, an analysis of the environmental benefits was conducted using PaLATE, a life cycle assessment (LCA) tool developed with RMRC sponsorship. The LCA analysis of four environmental parameters (energy use, water consumption, carbon dioxide emissions, and hazardous waste generation) showed significant environmental benefits when states used recycled industrial byproducts such as fly ash and recycled roadway materials such as recycled concrete aggregate (RCA) and recycled asphalt pavement (RAP).

Owing to the tremendous efforts of the United States Green Building Council (USGBC) and the development of the LEED rating system, a mechanism has been created to evaluate construction projects from a “green building” standpoint. Using a free, foundation industry-specific carbon calculator tool for this study, the carbon footprint of a theoretical project was evaluated for four separate foundation options on the given site, using consumption data from real projects. Two methods of ground improvement, dynamic compaction and aggregate piers were the first two options considered, the third option was driven pile foundations, and the final option was a full removal of the unsuitable fill material and replacement with imported structural fill. Results of the study indicated that under the assumed conditions, ground improvement programs can have a carbon footprint on the order of 2 to 6% of the footprint associated with full removal of the fill material to send to a landfill. As such, this paper recommends that further evaluation be given towards establishing a new LEED credit related to geotechnical construction issues, or at minimum, establishing a carbon footprint reduction scorecard that could be incorporated into the existing LEED infrastructure.

A national park was constructed at Al-Azhar district in the capital of Egypt. The park site was historically covered with several tons of fill and waste material dumped over decades. The fill material was in a dry condition and susceptible to considerable settlement upon wetting. A major potable water network which consists of tanks and pipes, with piled foundations, exists in the site. Considering the existing social and environmental hazards, due to the site location and its constituents, it was decided to transform the site into a national park serving the community. A sustainable geotechnical design was investigated and applied in order to eliminate the anticipated environment and economic hazards due to geotechnical construction works for such large site. Design or construction technique that might cause damage to the existing water tanks and pipes, or pollution to the surrounding environment was avoided. This paper presents case history on the sustainable geotechnical design successfully applied to the site of Al-Azhar Park.

Geotechnical engineers now have the tools to estimate total embodied energy (EE) and carbon dioxide (CO₂) emissions and may use this information in order to better incorporate sustainable development principles into ground improvement projects. In the early stages of a project, uncertainty arises in EE and CO₂ emissions estimates because many details regarding the specific materials and their sources may be unknown. Therefore, the influence of uncertainty on EE and CO₂ emissions estimates may be significant and should be determined. The streamlined energy and emissions assessment model is used in this paper to evaluate the influence of material haul distance on total EE and CO₂ emissions. The case history projects analyzed include the construction of 364 rammed aggregate columns for foundation support of Pearson Hall on the Virginia Tech campus and the installation of deep soil mixing columns to support an earthen embankment for levee LPV 111 in New Orleans, LA. The actual material haul distances were 8 km for Pearson Hall and ranged from 3.2 km to 1,130 km for LPV 111. Assuming no change in transportation mode or efficiency with increasing distance, it was determined that for each multiple of the as-built haul distances, total project EE increases by 4.9% for Pearson Hall and 4.5% for LPV 111; total project CO₂ emissions increase by 3.1% for Pearson Hall and 2.7% for LPV 111.