ICPTT 2014

The development and utilization of city underground space in China increases tremendously and rapidly, as does the underground space related to legal construction. Since the first department regulation on city underground space was promulgated by the Ministry of Construction in 1997, around 32 laws and regulations have been issued and implemented by the local authorities. These laws and regulations cover the city underground space management system mechanism, property ownership, surface relations, development planning, and transactions. However, there also exist some problems. Firstly, the coverage is small and the legal effect is low. Secondly, there exists some content conflict between different laws and regulations. Thirdly, some important contents are lacking relevant provisions. Therefore, some measures should be taken so as to further improve the need. Firstly, the existing laws and regulations on city underground space should be amended, supplemented and perfected. Secondly, the provisions related to city underground space in other laws and regulations should also be amended, complemented and perfected. Thirdly, national level laws and regulations must be formulated.

Failures occurring in buried pipelines are usually associated with structural damage externally induced by surface loading or permanent ground deformation. In the framework of structural health monitoring (SHM), this paper presents a real-time technique for safety evaluation of continuously welded underground pipelines subject to external interference by using quasi-distributed wireless inclinometers. Based on the multiple inclination measurements, a fitting model combined with indirect adjustment theory and the general solution of the differential equation of beam model on elastic foundation are developed to reconstruct the inclination equation. The deflection curve is then derived to locate the abnormal surface loading and permanent ground deformation. Stress is also calculated to evaluate the performance of the buried pipeline. The error propagation from inclination measurement to the calculated stress is investigated as well. Numerical studies verify the fitting model proposed in this paper, which is of great precision to fit the rotation equation as well as calculate the deflection and strain.

During the process of transporting gas, a mixed gas-liquid layer - formed by condensed gas (including CO₂) - leads to corrosion of T-shaped pipe elbows, which influences service life of pipelines, triggers various leakage disasters and causes heavy casualties and property damage. Based on domestic and overseas research, this paper puts forward the improved De Waard corrosion prediction model of gas pipelines by applying hydromechanics theory and considering the factors of gas flow rate and PH value. The paper calculates the flow field inside T-shaped elbows by using the fluid dynamics (FD) method. It analyzes the influence of flow field parameters on pipelines corrosion rate combining with particle erosion model, and raises the corrosion model of wet gas containing CO₂ pipeline based on hydromechanics theory. The field research on the application of this model shows that the major parameters influencing gas pipeline corrosion are the flow rate of media, turbulence kinetic energy and phase distribution. For T-shaped pipe elbows, the maximum corrosion position is the internal oblique confluence area. The results calculated by the model coincide well with historical statistical data and field testing results, so it verifies the correctness of this corrosion model. It provides a decision basis for maintainence and integrity management of gas gathering pipelines containing CO₂.

This article analyzes the reasons for internal corrosion of an old crude oil pipeline on the basis of historical data on corrosion failures, in-line inspection (ILI) results, elevation, physico-chemical analysis of sedimentation water from pipeline, EDAX analysis, transportation technology, Polarization curve and failure analysis of severe internal pipe corrosion. The results illustrate two points:(1) the corrosivity of sedimentation water is severe as the result of the combined effect of higher sulfate reducing bacteria (SRB), chloridion, salinity, operating temperature and flow-rate; and (2) the internal surface of a 15-kilometer downstream pipeline section close to an oil transportation station is bare without paraffin precipitation and directly exposed to the severely corrosive sedimentation water in the lower part of the pipe due to the high oil temperature.

In the light oil gathering process, paraffin deposits affect the normal operation of the pipeline, and several heating stations are set along the pipeline to ensure the safe transportation of crude oil. From indoor and field testing, the paraffin inhibitor can obviously improve the low temperature oil fluidity which realizes the low temperature transportation of light oil. In Ci 78 block, paraffin control in wellbore and low temperature transportation from wellhead to joint station pipeline are realized through the additition of paraffin inhibitor to the oil well at the wellhead, thus realizing the integration of wellbore paraffin control and pipeline low temperature transportation.

A kind of evaluation technique has been developed which includes an experimental apparatus and test method. The technique can evaluate the impact of erosion and corrosion to downhole string in a complex environment such as high temperature, high salinity, CO₂ or H₂S. It is difficult to control the quantity of particles in the previous methods which intake the particles by siphoning. This technique can solve the problem through the use of a screw feeder and can evaluate the impact of erosion and corrosion at the same time. It will help to study the damage mechanism of downhole string caused by high temperature, high salinity, CO₂ or H₂S. It also has an important significance to guide the optimal design and material selection of downhole string.

Due to the preferential corrosion (in the welds) and general wall thinning of the existing 30" Sea Water (SW) line from the SW Treatment Plant (STP) to Crustaceous Water Module 01 (CW01), new pipeline is being installed at the Greater Kuparuk Area (GKA) North Slope production field of ConocoPhillips, Alaska, in the 2013/2014 winter season. The new 30" x 0.375" WT x 75,000-ft.-long 5L X-65 pipeline, along with its components (block valves, flow meter, pig detectors, etc.), is being installed on the pipe racks adjacent to the existing 30" pipeline. The existing 30" pipeline will be abandoned in place. The construction methodology executed in the arctic conditions and constraints includes the following:• Pipe laid on the cross-country section included hydrotesting using sea water prior to tie-ins;• New road/caribou crossing and gravel pad crossing;• New Vertical Support Members (VSM) and Horizontal Support Members (HSM); VSM were drilled. • Utilization of ice roads during the winter for construction execution. • Fabrication and installation of pipeline anchors, pipeline saddles, and bends • Other pipe-laying activities (i.e., double-jointing, joint coating, insulation, and pigging). This article will present mobilization and construction execution efforts required in arctic conditions for completion of the 30" sea line project in a safe and efficient manner.

Based on spatial statistics, the paper used spatial autocorrelation to research spatial distribution patterns of geological hazards along pipelines, and then used this method in practice identifying geological hazard hot spots along pipelines. Compared with traditional geological hazards statistics method, this method can quantify the overall and local levels of spatial aggregation degree of geological disasters. Spatial location is taken into account when it is used to analyze spatial objects' relation, and its result is quantified. It is easy to sort when using and can be used to provide the basis for pipeline geological hazards.

Data management is the key to pipeline integrity management. With the promotion of integrity management, data change management of pipeline integrity - including pipeline change, high consequence areas change, and risk assessment result change - has increased frequently and importantly. This paper compares the mainstream database management technology and proposes the method based on historical data archiving to establish a spatio-temporal database for data change management, supplemented by GIS technology to achieve data change management of pipeline integrity.

Gathering and transportation pipelines of high sulfur gas field were generally owned with gas-liquid mixed flow, large flow and high velocity turbulent multiphase flow characteristics. Focusing on the gathering system of the Puguang high sulfur gas field, a gas-liquid two-phase erosion risk prediction was carried out based on a flow hydrodynamic numerical model. The shear force was applied to represent erosion characterization of the two-phase turbulent flow. The turbulence intensity was applied to represent characterization of turbulent mass transfer enhancement. Based on the grey relational analysis method and according to online corrosion monitoring data integrated with static corrosion experiment data, the corrosion prediction model of the Puguang gas gathering pipelines was established. The work that was done provided the basis for the transmission system of corrosion monitoring and safety management.

The construction process of an underground water-sealed rock cavern involves some complex types of rock. Block instability is a common problem during construction. In order to overcome the shortage of block theory and Unwedge (a software based on block theory that cannot analyze the specific block), sketch pictures have been developed to locate the specific block position and the existence of the block. By changing the span of blocks in Unwedge, the stability of the specific block was analyzed and proved through an engineering project. With the mentioned method, the blocks can be supported according to their specific position and size to reduce the support engineering and the amount of the project.

This paper proposed an evaluation factor index system of landslide hazards along a certain oil and gas pipeline during construction in southwestern mountains. A hazard evaluation was carried out for 36 single landslides via AHP-fuzzy. The evaluation results have provided scientific references for prevention and treatment of landslide hazards of the pipeline.

When the onshore, long-distance natural gas pipeline operates the normal gas transmission, its starting pressure is 4.5-6.4 MPa. Ending pressure is generally more than 1 Mpa. Once the injection happens, the gas leakage speed is big and the Reynolds number can reach 10⁴ orders of magnitude, which is a turbulent jet. It inevitably leads to an injection fire encountering the fire source and causing casualties and property losses in the industry-high-density and living-high-density areas. Therefore, studying the injection fire hazards and figuring out its basic parameters - such as the hazard radius, the hazard strength and the damage mechanism - are of great significance for effective prediction of the failure risk of the natural gas pipeline, effective protection for people's property and life safety. Based on the history data and test, the paper:(1) establishes and improves the relevant mathematic model; and (2) preliminarily establishes the consequence calculation method (which can quantitatively analyze and research the injection fire hazards resulting from the natural gas pipeline leakage), thereby providing the decision support for natural gas pipeline risk assessment, risk management, andpipeline maintenance, as well as the hazard consequence assessment after the injection fire occurred.

In this paper, a CFD mode is developed to analyze how the leakage time, pipeline pressure, leakage aperture, and the distance between leakage hole and buildings affect the leakage diffusion. A small scale, experimental set-up is also built up for validating the numerical model. The simulation results show a good agreement with the experimental data. They demonstrate that the numerical model has the potential capacity to provide support for integrity management, safety assessment, accident investigation and emergency measures for city gas pipeline system.

With the service life of water supply network (WSN) growth, the pipeline aging phenomenon has become exceedingly obvious in the old city area. The water supply network always has laid in the underground, so the maintenance staff cannot easily monitor pipe fault by modern detecting technology. In this paper, the algorithm of the decision tree is adopted to classify the pipe historical data. Basic property data (e.g., material, pressure, load, and distance to tank) in the water supply network can be used to establish a classification model. At the same time, establishment of the model is validated by another part of historical data. After modeling, Receiver Operating Characteristic (ROC) and Recall-Precision Curves (RPC) are used to assess the modeling performance. The purpose of this classification model is to establish the prediction model and then to show how to classify new input data. Finally, this paper instructs the monitoring staff on how to maintain the aging pipe in the future.

Attention has been focused on prevention of pipeline disasters for a long time. By summarizing the basis of past experience in the construction of the pipeline, the pipeline engineering geological disaster control now follows those prevention countermeasures:(1) establish a prevention concept of "early detection and early treatment" (with emphasis on "prevention"); (2) use a combination of prevention and treatment" for geological disasters; (3) reduce geological disasters from both macro (optimization pipeline route) and micro (specified construction) prevention; (4) in order to pay more attention to important areas, the areas are divided into emphasis prevention areas and general prevention areas, considering all stages of prevention work onto emphasis areas according to its whole life circle stages and putting limited resources and energies into these prevention areas of mass disaster-prone regions. Each stage of the project should consider disaster characteristics carefully. The prevention project should be easily constructed, economical and environmentally friendly.

Attention has been focused on long-distance pipeline disasters control for a long time. Summing up the lessons of the past, the Sino-Burma pipeline natural disaster control abandoned the idea of passive management and introduced a full life cycle and active protection concept. In the early stages of the construction, parties cooperated to select and optimize the pipeline and checked the survey reports carefully to make sure the preliminary data was right. In the design of geological disaster prevention, we should:(1) enhance communication with other professions and cooperate with each other in order to achieve optimal treatment results and cost savings; (2) create a dynamic design philosophy to make sure the design guides the construction and is optimized in the construction;(3) carry out the design evaluation, summarizing past experience in time; and (4) run-time monitoring and real-time protection.

With the development of SCADA systems, the monitored real-time data of a water supply network is more complete than before. Taking full advantage of the data to forecast the pressure of the monitoring points is the basis of water pipe network schedule optimization. A support vector machine (SVM) model for pressure prediction was established to solve the problems by making use of the data. Kernel function and parameters were chosen by means of cross validation. The EPANet example 1 and the water distribution system of City SZ were used to test the method. According to the EPANet example, the SVM method has a higher prediction accuracy and more stable results than those of the BP neural network. The example of SZ water supply network shows that RBF-SVM can be applied to predict nodal pressure in a network. The largest relative error of total results is 8.72%, and 85% predicted errors are smaller than 5%.

The determination of the water consumption variance curve is the important content in node flow distribution of a water distribution system. This paper studies the basic principle and method about the determination of the water variance curve of a city water supply network, and takes the practical engineering case of T city as an example. This paper has adopted the method of time series and cluster analysis to simulate the periodic change in water use. The water consumption variance curve of working days and rest days are made respectively and the difference between the two parts are analyzed. Two kinds of water consumption variance curve methods are compared and a method applied to this city is determined.

Based on the flow field numerical calculation, the three-dimensional turbulent flow of the centrifugal pump has been numerically calculated by Reynolds averaged N-S equations by using the RNG turbulent model and the SIMPLEC algorithm. The head, shaft power and efficiency at five different operating points are predicted by using numerical calculations at the design flow rate in the range of 0.6-1.4 times. The performance curves were drawn according to the calculation results, which were consistent with the performance curves obtained from the experiment. Through numerical calculation, the velocity and pressure distribution of the inner flow field of the centrifugal pump are obtained and analyzed. The internal flow phenomena and rules of the centrifugal pump are revealed. The calculation case shows that the 3-dimensional turbulent numerical calculation provides the theoretical basis for centrifugal pump structure optimization and performance prediction. The method shows a certain academic value and practical significance.

EPANET, a network modeling software, is widely used in water pipe network design, operation and management. However, due to lack of pipe diameter property when importing from CAD network topology, the pipe network modeling efficiency has been restricted. The EXCEL VBA function is known as being easy to learn. A program of automatic assignment procedure for pipe diameter of the water network based on VBA is given in the present work. It is easy to understand and greatly enhances the efficiency of network modeling. The EPANET INP file is used to be a data processing carrier. It makes use of VBA functions for data search and calculation and improves software coupled to solve practical engineering problems. It helps to develop and progress the water pipe network model through design, operation and management.

This paper summarizes the practical application of anti-corrosion coating for a horizontal directional drill (HDD) crossing pipeline, and presents the development of integrity protection techniques for anti-corrosion coating on HDD pipes, addressing the main advantages of Powercrete coating used for Yellow River HDD crossing pipe.

Drainage management and good practice in Shenzhen are introduced in the article. First, the existing drainage management for some main cities in China is presented, and the main character of each system is analyzed. Second, the article gives a brief introduction about drainage size, investment and construction system, operation and management system, administration system and Capital guarantee system. Last, the practice of good drainage pipe maintenance in Shenzhen Water Group Co., Ltd. is introduced, including daily maintenance, information management and innovative technology application.

The operation, maintenance, and construction of underground structures require a huge amount of energy and generate a significant amount of greenhouse gases (GHG) (Hendrickson 2000). The energy and GHG are generated from the process of extracting raw materials, producing and manufacturing new materials, transporting materials to sites, and installing materials (Junnila et al. 2006). Energy conservation and control of GHG are critical to ensure energy security for future generations and to alleviate the impact of climate change. This paper presents a new approach of Enterprise Carbon Accounting for underground infrastructure. The method is based on categorization depending on the size of the organization and its assets. Categorization of similar buildings and assets are averaged and analyzed as a unit. Outliers and averages of each type are then examined for causes, correlations, and future solutions. The proposed method will establish a carbon emission and energy use baseline for the large scale agency that owns and operates underground infrastructure.

Trenchless construction projects are typically delivered using the traditional design-bid-build (DBB) system. The DBB sequential process often results in inefficiencies and creates a knowledge gap between the contractor and engineer. Alternative project delivery methods (APDM) were developed to bridge the gap between contractors and engineers, and to help mitigate the resulting inefficiencies. APDM have been widely adopted in many industries, including highway and building construction. However, they have not gained significant popularity in the trenchless construction industry. This lack of adoption can be attributed to many different reasons, one of these being the comfort level of project stakeholders in implementing APDM. This paper investigates the comfort level of project stakeholders through a questionnaire sent to individuals in the trenchless industry. The findings demonstrate that there are different comfort levels for implementing APDM for each type of project stakeholder and across different APDM.

To solve the problem of optimal layout of seismic monitoring stations in a water supply network, a sample attribute matrix was built through the concept of coefficient influence. A dynamic classification model for optimizing seismic monitoring stations' placement in water distribution networks was proposed combined with dynamic classification method (DT). The iterative calculation process for the dynamic classification model was also offered. Firstly, the hydraulic simulation model for a leaky pipe network caused by earthquake was established based on the node pressure method. The flow values of each pipe under different working conditions were calculated by hydraulic simulation model and EPANET software; then, the flow influence coefficient matrix was built. Secondly, the dynamic classification method was introduced for optimizing the grading of all the pipes, and the key earthquake monitoring stations were selected for optimal layout combined with the actual situation. Finally, a sample network was calculated by the model and its relevant calculation programs. The analysis results show that the classification of pipes in the water supply network is reasonable and scientific, and seismic monitoring stations distribute uniformly in the water supply network. Furthermore, the model can wear off anthropogenic impact to a certain extent and enhance the monitoring effect in earthquake and economics of the network building.

Galvanized steel pipes are widely used for indoor water or gas distribution. Leakage in the pipeline system is prone to occur in screw thread connections as opposed to the tube itself. This work presents an experimental investigation on acoustic emission (AE)-based leak detection of galvanized steel pipe due to two forms of damage in the connection - screw thread loosening and a defect in the splicing tube. The waveform and frequency signatures of the AE leak signals are firstly observed. Regarding the fact that AE signals possess a wide frequency range and a broad spectrum, two cross-correlation methods based on wavelet transform are adopted for leakage locating, by either directly using the signals corresponding to a certain decomposition level or constructing an energy feature vector. It is verified that the involvement of energy features in these cases can improve the algorithm and put forward a more accurate estimation for locating leaks.

This paper researches the disturbance of the soil body and adverse effects on buildings with underground construction utilizing the pipe jacking method and how to cope with these problems.

According to the requirement of offshore installations, the corresponding simplified computer simulation model for subsea pipeline-laying process with inline structures has been built. In order to investigate the main parameters and guarantee the structural safety of the subsea pipeline, static and dynamic analyses based on simulations are carried out. In static analysis, the result of the pipe-laying posture and equivalent stress of pipeline under different residual tension is given. In dynamic analysis, the effect of environmental conditions on the installation process is studied. The simulation process can be adopted as the theoretical basis for the offshore installation. By using the simulation, installation efficiency can be improved and the risk in offshore engineering can be reduced. The process of the simulation method can be spread to the realization of other types of large offshore installation activity.

The purpose of this paper is to answer the real dilemma and the theoretical relative blank on the legal nature of farmland for water supply and drainage underground pipeline passage in China. For methods of comparison, legal norms analysis was employed. The research showed that the farmland for underground pipeline passage was the main way for the construction of a water supply and drainage underground pipeline. The farmland for the underground pipeline passage had characteristics of limited and partial use, long-term use and restricted use, which accorded with the essence and legal condition of rural servitude. It is conducive to the realization of a win-win situation among all parties and in maintaining the order of farmland use after setting the passage right of the water supply and drainage underground pipeline for rural servitude.

The thermal exchange coefficient between subsea soil and buried pipeline is a very important parameter for submarine pipeline design. It has a complex relationship with the heat conductivity coefficient of subsea soil and depth of pipeline buried below the seabed. To determine the thermal exchange coefficient, soil samples of different depth under seabed are sampled and tested. According to test results, 3.7W/(m² K) of thermal exchange coefficient of subsea soil is recommended. To verify it, temperature drops of two submarine pipelines -SZ36-1 and BX submarine pipeline in Bohai Sea in China - are calculated and compared with practical temperature drop of two pipelines, respectively. The computational results are very close to practical results. It indicates that the recommended thermal exchange coefficient is suitable and reasonable for a submarine pipeline. It is very helpful for the designers and engineers to determine the crude oil temperature drop of submarine pipeline at the stage of pipeline design.

Taking the spanning pipeline of the Wei-Hui engineering project as an example, a spatial correlation of the wind field simulation program is compiled by using MATLAB. As a result, the power spectral density function for simulation of the wind speed is in good agreement with the target power spectrum, meaning that this method has relatively high accuracy. Converting the wind speed into wind load and imposing it onto the finite element model of suspension cable crossing pipeline, vibration response analysis is made. The structure displacement, acceleration time history curve and the stress distribution of the components are obtained. The results show that the suspension cable crossing pipeline structures under wind load are safe. This analysis also provides a reference for the other wind-resistant design of similar structure.

The fiber optic cable (FOC) is easily damaged in particular areas in the oil (gas) pipeline project. Owing to the same-trench buried method with pipeline, the installation and protection of FOC is always limited. The purpose of this article is to discuss the installation and protection method in these particular areas.

Recently, reinforced thermoplastic pipe (RTP) is increasingly applied in the oil and gas industry. Since tensile behavior is a fundamental property of RTP, the theoretical method and numerical simulation are both used within this paper to study the behavior of RTP under tension. Using the theoretical method, the model proposed by Knapp is modified and further applied to RTP, considering the interaction between pipe and wires as well as material nonlinearity. Equilibrium equations are derived based on the principle of stationary potential energy. Using the Newton-Raphson method, the problem is solved by an iterative procedure. As for the finite element model, solid and truss elements are used to simulate the HDPE layer and wire, respectively. Results from both methods are compared and an agreement between the theoretical method and numerical simulation is obtained. Both methods can offer valuable advice for RTP design and application.

The sliding impact on pipeline across a landslide was analyzed by numerical simulation. Two cases of landslide along the Sichuan to East gas pipeline were simulated with pipelines in the front or in the rear of the landslides, respectively. The mechanics numerical simulation model was established by ANSYS finite element analysis software, and the pipeline stress and strain were simulated by using the FLAC^3D software. Comparative analysis was carried out to the critical stress and displacement of pipeline under the loading of a landslide in both situations. Results show that when the pipes go across the landslide, the maximum deformation appears in the middle part of the pipe and the maximum stress appears at its two ends. The two ends of the pipeline are prone to damage. Yield damage is more likely to occur in the pipe crossing the front of a landslide, and the risk of damage to the pipe is relatively lower when the pipeline is buried across the rear of a landslide.

In order to find out characteristics of pipe bursts, 190 burst events reported by domestic web news in 2013 were collected and analyzed. The statistical analysis results showed that bursts often occurred in months when the weather changed or was bitterly cold. Bursts occurred most frequently in the time period of 5:00-17:00. Generally, main roads, intersections and construction sites were more likely to become events locations. Heavy trucks passing, aging pipes, barbaric construction and changing weather were factors affecting pipe bursts. The diameter of burst pipes concentrated in DN200~DN600, DN800 and DN1000~DN1200. The probability of bursts might increase when pipes age between 20~40 years. The relevant department dealt with bursts in time, and about 70% of the burst problems could be solved in 24 hours.

Choosing the reasonable depths of a buried pipeline is one of the crucial issues for long-distance gas transmission pipelines. This paper focuses on the mechanical analysis of a pipeline with a different buried depth under the driving force of a landslide. The relationship between the bending moment, shear force, displacement and buried depth of pipeline can be derived under certain assumed conditions. The result of the Zhong County-Wuhan City gas transmission pipeline project shows that the moment reaches a greater value at the junction and the midsection of the pipeline and the shear force reach maximum at the junction along with the increase of buried depth of the pipeline. On the basis of the stress characteristics of deep-buried pipeline in engineering practice, it can improve the safety of a gas transmission pipeline by enhancing the piping material performance at the junction and the middle part of the pipeline.

Based on Hencky's total strain theory of plasticity, the limit bending capacity of steel pipes can be determined analytically assuming an elastic-linear strain hardening material. The simplified analytical solution is proposed as well. Good agreement is observed when limit bending capacities obtained from analytical solutions are compared with experimental results from full-size testing of steel pipes. It is shown that pipe considered to be strain hardening yields a higher bending capacity than that of pipe assumed as an elastic-perfectly plastic material. Thus, the ignorance of strain hardening effect, as commonly assumed in current codes, may underestimate the limit bending capacity of steel pipes. The solutions proposed in this paper are applicable in the design of offshore and onshore steel pipes, supports of offshore platforms and other tubular structural steel members.

Aimed at the phenomenon of leakage from the pinhole of a high-pressure buried natural gas pipeline leading to frozen soil, the model of natural gas pipeline pinhole leakage and stationary temperature field was built. An example was analyzed based on fluid and gas dynamics. The model of a transient temperature field was built and an example is analyzed based on Green. The results show that the natural gas pipeline pinhole leakage can lead to frozen soil in a little while. At thebeginning, the frozen soil's curtain increases rapidly. As time passes, the curtain increases slowly until it is transient. The higher the density of dry soil, the bigger the frozen soil's curtain. The more water contained in the soil, the bigger the frozen soil's curtain.

There are more attendant problems with China's urban pipeline project developing rapidly, and the density of the formation surrounding the pipeline becomes an important issue. Therefore, the detection of the position and scope of less density and the cavity area around the pipeline have become top priorities of piping. This paper combines the process of a geological radar to detect the stratum around a pipeline in Xi'an to introduce the application of ground penetrating radar to detect less density and the cavity area around the pipeline. The conclusion shows that the amplitude of the radar reflected wave is in an approximate inverse relationship with the density of the stratum.

Loosening of the stratum top of the pipe occurs in the process of jacking pipe, and defects of surface settlementmay may possibly be caused. Ground penetrating radar (GPR) is used to detect the location and depth of all areas which are not dense and void on the top of the pipe and to make treatment project effectively. Based on the working principle of GPR, this paper combines the process of detection and analysis for a sewage project in Xi'an and introduces the application of GPR to detect the defects of jacking pipe. An important conclusion from model research has been made that the relation between the amplitude of the GPR reflection and the density of the stratum is approximately proportional.

In this paper, principles, approaches and techniques of electromagnetic method applied to detect underground pipes are introduced. Distribution and features of horizontal and vertical components Hx and Hz of the geomagnetic field generated by direct coupling are analyzed theoretically and technical requirements of Frequency Domain EM in catering to detect underground pipes are summarized in the end with the application effects elaborated through an application case.

Buried pipelines are corroded by or even leak due to various factors in underground harsh environment for a long time, causing great economic losses. Therefore, it is of great significance to do research on defect detection and evaluation method, and to accurately and efficiently measure buried pipeline corrosion status. Each newly developed non-destructive testing (NDT) technique leads to another, more operational one that may be adapted for the purpose and finally implemented effectively. This paper presents some critical NDT technologies for the pipeline detection, from the conventional to the advanced. In this paper, the Ultrasonic Guided Wave (UGW) and Transient Electromagnetic Method (TEM) and the field test are discussed. This paper will discuss these test results to Ultrasonic Guided Wave inspection technology in buried pipeline inspection. In this paper, a transient electromagnetic method is used for nondestructive testing of in-service buried metal pipelines in a trenchless state. The results demonstrate that the transient electromagnetic method is a valid and practical method for testing of the corrosion of buried metal pipelines.

It has been a prevailing practice of pipeline construction in China and all over the world to lay the optic-fiber cable (silicon-core pipe) same-trench buried with oil (gas) pipeline. At present, the total mileage of optic-fiber cable (silicon-core pipe) laid using this technology has reached 40,000 km in China, among which many pipeline projects go through a lot of mountainous areas and hilly lands, such as:Zhongxian-Wuhan natural gas pipeline, Lanzhou-Chengdu-Chongqing product oil pipeline, and China-Myanmar oil and gas pipelines. The future central Asia gas pipeline line D will also go along a large quantity of mountains and hilly lands. These areas are characterized by complex and up-and-down landforms, large drop height, many steep slopes and limited construction operation, which is a challenge for the stability and reliability of the pipeline and the same-trench buried optic-fiber cable lines. It is a certain threat to the construction and long-term operation. This paper will focus on two kinds of optic-fiber cable-laying methods - direct burial optic-fiber cable and pipeline optic-fiber cable - and build the mechanical model of laying optic-fiber cable in large slope area, study the tension situation of optic-fiber cable in the process of construction and long-term operation, and put forward corresponding protective measures in order to improve the engineering quality of laying same-trench buried optic-fiber cable, which will ensure the long-term reliability of long-term operation of the optic-fiber cable line.

This paper speaks to the problem of cuttings suspended difficultly when drilling in coarse sand formations. We research the right kind of drilling fluid for the program and the effects of components on properties of the drilling fluid. The test results show that with the content of bentonite, NaOH and CMC increasing, the viscosity of drilling fluid shows a growing trend. NaOH has a greater impact on the ability of suspended cuttings. By orthogonal testing to determine the optimal drilling fluid, it provides a reference for the construction site.

The largest curved jacking pipe roofing tunnel - Gongbei Tunnel - is under construction at present in Zhuhai, China. It is a significant part of the Hongkong-Zhuhai-Macao Bridge, using the curved jacking pipe roof method and freeze technology. Crossing the Gongbei Port, the total length of this tunnel is 255 m. It consists of a transition curve that is 88 m in length and a circle curve that is 167 m in length. The supporting structure is made up of 36 steel pipes with diameter of 1620 mm, forming a huge oval section shape of about 22 m in width and 24 m in height. Therefore, the huge dimension decides the construction of jacking pipes must cross in multilayer soft soil, such as:artificial fill; clay; very soft, silty clay; and, sandy gravel soil. In addition, the highest groundwater pressure is close to 30 m at the bottom of tunnel. So, this project is faced with complex geological conditions. Four AVN1200TC pipe jacking machines of Herrenknecht have been used to install the steel pipes string. This paper:(1) provides an overview of this project and (2) summarizes the challenges faced and the techniques used to handle the difficulties encountered during construction.

In this paper, the accident-prone status of the gas pipeline is considered and the FAQ in the gas pipeline construction management process is summed up. The author proposes a number of measures to strengthen the management of gas pipeline construction and raises the awareness of all participants to better manage the gas pipeline construction.

With the construction of the first, second and third pipelines of the West-East Gas Transmission Pipeline Project, Myanmar-China Oil and Gas Pipeline and other national key oil and gas pipeline networks, long distance, large diameter, high pressure, complicated geological, hydrological and environmental conditions become the key points for pipeline construction. As the critical works for the whole pipeline construction, the crossing project has inevitable construction risks. However, qualitative analysis was mainly applied for comparison and selection of the previous project proposals. Concerning risk analysis, focus given to the engineering risks while risks of construction period and investment - as well as the environment risk resulting there from - are always ignored. This will probably lead to the proposal selection going the wrong way. The risk events encountered during implementation of the project may lead to delay of the construction period and underestimated (or anticipated) investment. For some cases, a temporary construction proposal is adopted to ensure the construction will be accomplished as scheduled. In this case, works will be wasted and the whole project will be forced to stay at a passive state. To obtain a reliable, feasible and rational design proposal, it is inevitable to perform comparison and selection of proposals based on the risk analysis. Based on the risk analysis, comparison and selection of the crossing design proposals can proceed in the following steps:(1) A number of possible design proposals (including proposals for large excavation, directional drilling, shield tunnel and pipe-jacking tunnel), shall be preliminarily determined by combining the factors of engineering geology, hydrology, weather, site, and environment; (2) A variety of risk analysis shall be conducted for all of the design proposals to be selected through comparison; (3) A comprehensive comparison shall be performed for the risk analysis result of each proposal, and the design proposal which involves low risk other than high risk shall be selected according to the actual conditions of the project as well as the Employer`s requirements.

The concept of DBS is introduced to the water supply network planning stage. Based on natural conditions, and combined with the situation of the pipe network layout, the DBS methods and principles are discussed. According to the hydraulic model, the DBS planning programs - which have been assessed by EPANET 2.0 - satisfy the water security. Compared with the traditional planning programs, the implementation of DBS in the planning period can save construction costs. The paper attempts to:(1) enhance the water supply network planning and design standards, and (2) improve the water network management and operational levels.

The slurry balance jacking process often generates surface uplift or cavity around thr tube because of an irrational exchanging slurry rate. Grout reinforcement can prevent and control the cavity effectively and prevent building subsidence above the pipeline during the construction process. Combined with the Xi'an sewage pipe jacking project, for instance, the numerical simulation method and engineering analogy method have been used to analyze the soil layers' displacement during grouting reinforcing cavities. Results suggest that while using 0.28~0.3MPa grouting pressure to reinforce cavities around tubes, uplift values of ground surface and displacement values of tubes can meet requirements.

In this article, the author describes and categorizes pipeline trenchless rehabilitation technologies, and introduces several commonly used pipeline trenchless rehabilitation technologies, including pipe lining repair technology, pipe mortar jetting technology and pipe bursting technology. The author emphatically introduced pipe lining repair technologies while also expounding on the advantages and limitations of these types of pipe lining repair technologies.

During the lifetime of a pipeline, the point is reached where the cost of water loss, leakage management, maintenance and repair works, together with the poor service to the customer justifies its replacement or rehabilitation. Trenchless rehabilitation techniques can have a lower cost and cause substantially less disruption to existing assets in the general population than conventional `open cut' techniques. As trenchless technology has developed and increased in use, so has the use of polyethylene pipes in applications such as slip lining, close fit lining and pipe bursting. The majority of pipeline renovation and replacement techniques now use polyethylene as their principal pipe material, and the techniques have been developed to the point where they have been used to rehabilitate pipelines of up to 1,400 mm internal diameter. This presentation will give an introduction to the different methods by which water pipelines can be rehabilitated using polyethylene pipes and liners through the use of a variety of trenchless technology techniques. It shall also explain how engineers and other technical staff working for water utilities can use the standard ISO 11295 to help identify and specify the most appropriate technique for their particular situation. The original polyethylene pipe materials were not intended for such applications, so the greater use of polyethylene in trenchless technology has been a key driver in the development of tougher materials. One development has been PE100 materials that have a high resistance to slow crack growth through the wall of the pipes. Such materials are referred to as HSCR PE100 and PE100-RC. The presentation will explain how slow crack growth can be initiated by the use of trenchless technology applications and how the new generation of PE100 materials resist the growth of cracks through the pipe wall.

The delivery process of the An Yong oil pipeline is very complex with:(1) variable delivery insecurity; (2) inadequate energy; (3) a serious lack of variables; (4) variable temperature control technologies-based operations in the production running to/from the 2009 "3 • 14" condensation pipe accident. The low transmission capacity problem of the An Yong oil pipeline in snowy days and rainy seasons running is more prominent. The variables and variable temperature control technology- based operations are particularly important. According to the variability of crude oil, to control the temperature of crude oil out of or into the station or through valves in different seasons (using the Muyu-Haojiaping segment as an example in this article), people can calculate the temperatures of outbound crude oil under different transmission capacities in different seasons. This helps to guide the actual production running of the An Yong oil pipeline.

In order to reduce the tee-joint's thickness and manufacturing cost, a series of large diameter and high-strength tee-joints are manufactured based on the equivalent strength design principles. The burst pressure of tee-joints is obtained directly by a series of burst tests. In addition, numerical simulations are carried out to evaluate the burst pressure capacity of a tee-joint. The influence of the fillet radius and the thickness of the branch are also discussed. The results of this paper may provide guidance in the design and manufacture of a tee joint.

A new borehole cleaning method used along with the normal circulation borehole cleaning is presented. The post-grouting pipeline is developed through optimizing design and modification. The added instruments - T-joint, check valve, and annular borehole clearing device - are summarized. The post-grouting pipeline is not only used for post-grouting, but also for borehole cleaning. Compared with the traditional normal circulation borehole cleaning method, this method can obviously improve the efficiency of the borehole cleaning. It can make up for the limitations of the normal circulation borehole cleaning, which is usable only for common small-medium piles. Compared with the air-lift reverse circulation borehole cleaning, it can be noted that the new method is much easier to construct and requires fewer workers. Besides that, the annular borehole clearing device continues to spray compressed air and cleans up the bottom sediment. Its goal is to further cement the effects of borehole cleaning. Therefore, the new borehole cleaning method has obvious advantages in every respect, and it is worth generalizing and applying in the field of pile foundation engineering.

In terms of pipeline operation, this article studies the problem of the pipeline optimization operation in low flow and super flow for operating safely and economically with energy saving. Ultra low-flow tests are done on low-flow pipelines to find the minimum flow of the pumps. More research is done on blending transportation of different oils, intermittent transportation of wax-bearing crude, drag and viscosity reduction of high solidification point crude oil and the shutdown and restart of the pipeline. The ladder-flow mode is for the larger span pipeline to reduce throttling and pressure energy lost for the safe operation in low pressure. Based on the data analysis - such as pressure, electric energy, parameter of the pumps, ultimate load, and best operating range - the best operating flow can be acquired by the SCADA system with related software such as EMP and data analysis software. It can provide theoretical support for selection of optimal pumps. In later stages of pipeline reconstruction, problems like mismatch of motors and pumps, improper pump selection, more throttling and energy loss are found frequently. It suggests that reform should be carried on according to the practical situation and long-term plan to avoid the aging of equipment or overload operating. In summary, the appropriate flow of the pumps will make sure of optimal operation.

According to structural stress analysis in the piping engineering field, a package of parametric command is advanced by developing a user graphical operation interface with Visual Basic to solve the reality of complex commands and operation in general finite element software. Analytical software is transferred in the background and results are output to the user interface by a pipe stress parametric computer-aided analytical platform. The engineering efficiency is greatly improved by this platform by making it convenient for engineering members to do analysis and operation.

A volcanic reservoir is located north of Songliao with a depth of 3500~4500 and temperatures of 130°C~170°C. The formation lithology is compacted and crustal stress is high. The volcanic formation mainly grew in the Klyc and Fire stone mountain group in the longitudinal. Drilling depth of volcanic formation in the north of Songliao is distributed in the 4000 m or even. With the increase of well depth, the rock strength, drillability and hardness obviously changed. Average drillability grade value was beyond 7, and average hardness was 2400MPa. High hardness and drillability grade value greatly reduced the rate of penetration of deep volcanic formation.

Long-distance oil pipeline controlled the hydraulic and thermal system through the SCADA system. Hydraulic controls included a stable and non-stable condition pressure control while thermal control mainly ensured that the downstream pitted oil temperature was 3°C higher than the freezing point. Major running processes of crude oil pipeline contained integrated heat treatment, heat treatment heating and normal atmospheric temperature transportation technology. Large contaminated transport processes might be applied to many kinds of oil transport to reduce the risk of pipeline operation, so as to reduce human operation. A water hammer protection program was an automatic protection procedure used mainly in the abnormal working conditions of the pipeline, which had been applied to almost all long-distance oil pipelines. Pipeline running operation included operation under normal conditions. abnormal conditions, and emergency conditions. The dispatchers needed timely and effective operation to ensure that the pipeline runs safely under abnormal and emergency conditions.

It is very important to detect underground pipes for urban planning, designing, construction and management. To know the distribution of underground pipes, GPR is available to provide real-time profile diagrams on the site which are clear and direct because of its high resolution, quick detection and non-destructive feature. The radar is efficient - especially when conventional methods fail to detect - and it is applicable to the detection of all kinds of metal and non-metal pipes. In this paper, the detecting principles, methods, and techniques of the radar are introduced. In addition, the paper also analyzes and summarizes the features for underground pipes made from different materials shown on radar image profiles with application cases in order to prove its effectiveness.

Allowing for the shortcomings of the existing dynamic interaction models of pile and pile end soil, this paper presents a new model to simulate the dynamic interaction of pile and pile end soil - namely, fictitious soil pile model. At first, finite soil layers below pile end are modeled as fictitious soil pile whose cross-section area is the same as that of the pile. Meanwhile, the surrounding soil layers of pile are modeled by using a plane strain model. Then, the semi-analytical solution of longitudinal dynamic response at the pile head in time domain is derived by means of the Laplace transform and impedance function transfer method. Based on this solution, a parametric study is conducted to study the influence of parameters of soil below pile end on the longitudinal dynamic response at the pile head.

Two kinds of laboratory test methods to obtain rock salt deformation parameters are introduced using elasticity theory to deduce the formula for calculating the rock salt deformation parameters with conventional tri-axial compression tests. On this basis, comparative analysis of the deformation parameters - which are obtained by uni-axial and tri-axial compression tests to the rock salt specimen of certain rock salt cavern gas storage - shows that compared to using the uni-axial compression test method, the deformation parameters obtained through tri-axial compression test are much closer to the actual deformation parameters. If the deformation parameters of rock salt are obtained based on the uni-axial compression test, there is a greater impact on the result of elastic modulus and shear modulus when people take different sections of the stress-strain curve. Deformation parameters obtained in a perfectly elastic deformation section are most reliable. Research results provide a reference to reasonably determine the deformation parameters of rock salt.

The Very Low Frequency (VLF) electromagnetic method is an important means of petroleum exploration. The application of trenchless guided boring technology broadens the VLF electromagnetic waves in the range of applications in engineering practice. It uses orientation instruments to measure intensity and phase of the specific VLF electromagnetic wave launched by near-bit probe for bit space locating and orientation of drilling information. Comparing the production ways of the VLF signal source and the characteristics of the principle, this paper presents a VLF standard sine wave signal source design scheme based on DDS and FPGA. The latter uses frequency modulation digital sine signal generator and frequency measurement to produce a standard sine wave signal. Invoking coarse and fine adjustment control words, this signal source naturally achieves rapid, continuous and accurate frequency modulation. It's of many remarkable characteristics, such as low signal noise and low power consumption. The FPGA, compared with the DDS digital synthesis source, is an ideal choice of the new probe signal source due to its bigger chip memory, more convenient and quick signal modulation, and faster processing speed.

In the injection-production process of gas storage salt caverns, temperature and pressures change inside the dissolved chamber. At the same time, the gas exchanges heat with the surrounding salt layer from conduction and convection heat transfer to form an unstable temperature field in the wall. This paper applies a control volume mass conservation equation, an energy conservation equation, a continuity equation and a gas state equation to create a thermal analysis model in the injection-production process of gas storage salt caverns. It considers the characteristics of melting heat transfer process chamber, coupled with wellbore flow to calculate, and obtains the analytical solution.

The purpose of this article is to research the optimal selection of pipeline route program and ensure the rationality of the selected result. Combined with the advantages of the analytic hierarchy process (AHP), this paper analyzes the selection of the evaluation indexes and the content of the comprehensive evaluation. In consideration of the influencing factors for route selection, the evaluation index system is built and a systematic method which is suitable for the evaluation and selection of the pipeline route is proposed. Finally, combined with an example of some city, the process is realized and the results are reasonable and reliable.

The contribution of this paper is to summarize the exit Application (APP) of a pipeline Fiber Optical Cable (FOC)-based system with an oil (gas) pipeline background, as well as making a forecast about the developing direction of a pipeline FOC-based system APP according to the various technologies of optical fiber sensor. The FOC mentioned here is buried in the same trench as the oil (gas) pipeline.

This paper introduces some methods of transporting oil pipeline motor fault diagnosis. The methods include:(1) the physics method diagnosis; (2) the fault diagnosis method based on Probabilistic Neural Network; (3) the fault diagnosis method based on wavelet singular value decomposition; and, (4) the fault diagnosis method based on data integration technology. Real objects are used to verify the fault diagnosis method based on data integration technology. Good results have been acquired.

Wave velocity is the main physical parameter of an ultrasonic wave CT test; it can distinguish the change of strength and density in a reinforced section. The absorption coefficient is the main physical parameter of electromagnetic CT; it can determine the distribution of the reinforced section. CT was applied to evaluate the grouting effect of group piles in the Su-Tong bridge. According to the results of coring and the CT test, it is practicable to apply ultrasonic wave CT and electromagnetic CT synthetically to test the grouting effect of super long piles.

Quantitative Risk Assessment (QRA), as a new technique, is widely applied in construction and operation for oil and gas pipelines. However, QRA technology has usually been applied for land use or making maintenance plans during construction or pipeline operation, respectively. Thus, it has been applied less for station design of the pipeline. This paper analyzes the risk of a gas station in China by using QRA technology, and it provides suggestions for station design according to the assessment results.

Natural gas is a flammable and explosive substance. Fire accidents may happen when leaking natural gas comes in contact with flame and, consequently, leads to injury to people and loss of property. It is very important to simulate fire accidents from natural gas leaking from a pipelineand to determine the influence scope and consequences of the evacuation of people. The major research of this paper involves building a model of a natural gas fire accident and then calculating the flame length and thermal radiation.

Valves play an important role in a water supply network, especially when a portion of the network needs to be isolated for repair or rehabilitation of broken components. To evaluate the valve-based reliability of a water distribution system, the concept of "segment" is proposed. When it is necessary to shut down during planned and unplanned maintenance, a segment - comprised of a cut set of pipes and nodes that is bounded by valves - is the minimum isolation unit. In this paper, the concept of reliability is defined as the ability of a network to adequately provide for the demands of consumers within specified limits of pressure. Finding the optimal strategy of valve shutdown and assessing the reliability of the water distribution system are two main issues which this paper addresses. A segment and outage segment generation technology will be used to divide the entire system into multiple segments, which contains a portion of pipes and nodes. According to the given general statistics information on the segment, we can find an appropriate shutdown scheme and assess the reliability of the system. At the end of this paper, a case study is presented in which a Chinese city pipe network is analyzed and assessed, and an optimization scheme is proposed.

In this paper - using the theory of vulnerability analysis of vehicle CNG stations for risk analysis - we find all kinds of factors in the CNG gas system which may affect the system in accomplishing its function and the weak link in which problems. We proposed the elements of the system for the vulnerability assessment of CNG stations system, and establish the evaluation model. Compared with traditional safety assessment methods, the vulnerability assessment method can improve the weak link of the system and support the stable realization of the whole system function

This paper discusses risk identification, effective risk reduction methods, controlling measures for key construction procedures and impacts to the environment during HDD construction projects.

Landslide is one of the most familiar geological hazards that happen in mountainous areas, the deformation of which can be of great threat to the safety of buried gas pipelines. In accordance with the characteristics of landslide development along the Zhongxian-Wuhan pipelines, the spacial relationship between landslide and pipelines was summed up. On the basis of engineering geology, elastic mechanics and structural mechanics, the internal force and strength of the pipelines under the action of landslide deformation were analyzed in theoretical calculation. Safety evaluation problems regarding the influence on pipelines due to landslide under thrust from different directions are discussed. The research shows that:(1) under a landslide lateral sliding force, opposite sides and the central part of the pipelines are much more easily damaged, especially at both ends; and (2) under the role of landslide longitudinal friction, the upper side (tensile) and the lower side (compressed) of the pipelines are easily damaged, especially in the lower part of the pipelines. Through the research of engineering practices, a conclusion was reached that a smaller sliding force (i.e., q = 4.5N/m) or slighter whole-round deformation of landslide (i.e., uk = 5mm) is able to lead the stress of gas transmission pipelines to an unsafe condition.

In this work, the application of the novel heat on-line partitioning (HOP) process to a traditional X80 pipeline steel by using Gleeble-3500 thermo mechanical simulator has led to the development of a new kind of duplex microstructure comprising bainite matrix and martensite-austenite constituent (MA) as a second phase. The effects of partitioning temperature on microstructure evolution, mechanical properties and retained austenite content of (B+M/A) X80 pipeline steel are researched by means of mechanical property test, microscopic analysis and X-ray diffraction. The study results suggest that the strength level of the steel subjected to the HOP process increases at first and subsequently decreases, while the elongation change in the opposite trend of the trail Steels with the increase of partitioning temperature. This is due to the synergistic effect of the increase in the retained austenite fraction, the decrease in carbon supersaturation in bainite, the change in the dislocation density in bainite matrix, and the formation of transition carbide. Meanwhile. in the early stages of the low-temperature partitioning process, carbon partitioning from bainite to austenite plays a dominant role in the stability and content of retained austenite. With the increase of partitioning temperature, the content of retained austenite presents the pink distribution, as does the effect on the plasticity. Therefore, the elongation is sensitive to partitioning temperature.

A settlement calculation method of super-long pile in deep soft soil area is proposed in this paper. The lateral friction function of super-long pile is simulated by a modified hyperbolic model. With the vertical load transfer function, the analytic solution of pile-bearing capacity is deduced for homogeneous soft soil. An example is given to verify the method. Finally, based on the method of this paper, the main parameters of pile settlement of super-long pile are analyzed. The results show that the values of pile diameter and pile-soil stiffness are more sensitive to pile settlement. The super-long pile settlement decreases nonlinearly with the increase of the pile-soil stiffness and pile diameter. However, the pile length has a relatively minor influence on the super-long pile settlement.

A water-sealed system affects the normal usage of an underground oil storage cavern. To make sure that the water seal is in good condition, continuous tunnel water inflow is needed. A reasonable tunnel water inflow is larger than local seepage and smaller than unlimited water flooding. Different shaped tunnels have various water inflows in the same working conditions. Different working conditions also may lead to different water inflows. The FEM software ANSYS thermal module can accurately simulate the underground inflow of various shaped tunnels or various working conditions. Results show that tunnel shape affecs inflow less than 12% and operating conditions' inflow is about 24% less than that of construction conditions.

Numerical simulations of shallow-buried, large-span tunnels have been performed in this study for tunnel excavation method selection among:(1) the both-sides heading method; (2) the three-bench temporary invert method; and, (3) the three-bench seven-step method. Stress and deformation of surrounding rock and safety of support structures have been analyzed for different methods during the excavation process, and the conclusions have been drawn as follows:(1) For the restraining effect of surrounding rock, the both-sides heading method is better than the three-bench seven-step method, and the three-bench temporary invert method is the worst; (2) Comparing to the both-sides heading method, even though the deformation of the three-bench method is larger, the stress in surrounding rock has been effectively released in this way so that the load acting on the supports will be relatively smaller. By using the pipe-roof early support technology in the three-bench method, the safety of construction can be ensured and the construction period can be reduced; (3) For the three-bench temporary invert method, since the excavation face is relatively big, the stability of the working face is poor. In addition, the assembly and disassembly for temporary invert is time-consuming with higher cost. For three-bench, seven-step method, the surrounding rock deformation of the tunnel cross-section is larger and the plastic range is wider. However, all are within the safe range and the safety of the excavation face can be ensured by the core of soil reserved in this method. Hence, the three-bench seven-step method is a reasonable method because it can accelerate the construction process and reduce cost, while ensuring the supporting structure's safety and excavation face stability.

Previous research on soil compaction effect mainly focused on single pile, and the analysis of the effect in the group piles was less. In the actual process, though, the design and construction of pile foundation engineering are based on the form of group piles. In order to further study the effect of construction of group piles on an underground pipeline, a three-dimensional entity model is adopted. The displacement penetration method is used to complete the process of piling. The friction between piles and soil, pipe and soil, large deformation and nonlinear factors are taken into account. The process of piling is more in line with the actual process. Taking the penetration of row piles for example, the numerical simulation of the static pressure pile is carried on under the condition of different piling sequences and the change of stress and displacement are analyzed. The results show that all kinds of stress and displacement of underground pipeline produced by the penetration of row piles increase cumulatively as the penetration of each pile and the stress and displacement of pipeline produced by the penetration of each pile are related with the sequence of piling.

An underground utility tunnel (UUT) FEM model is established under three types of seismic wave incidence - P wave, SV wave and Rayleigh wave - to investigate the influence of the wave type on UUT. It draws the conclusion that SV wave is the key factor resulting in the shallow buried UUT horizontal vibration, while P wave and Rayleigh wave induce the vertical vibration.

This essay introduces the conventional disposal method and its advantages and disadvantages for the domestic sewage in the station of the long distance pipeline. It analyzes the necessity of net zero discharge of domestic sewage in the station. After analyzing the factors, such as sewage quantity and treatment process selection, the essay discusses the exploitativeness of net zero discharge for the station domestic sewage.

Accurate assessment of pipeline settlement induced by shield tunneling is important for the safety of underground pipelines. This paper takes the Hangzhou Metro Line No. 1 as background. A three-dimensional model is established using FLAC^3D to investigate the effects of shield tunneling on existing pipelines in transverse and longitudinal directions. In combination with the monitoring data, the effects of the excavation of the left line and right line on pipeline settlement are analyzed respectively. The results show that a transverse pipeline is relatively more dangerous than a longitudinal pipeline. Further parametric studies are made on the transverse pipeline, including burial depth, pipeline material and soil stiffness. The influence of burial depth on pipeline settlement is very small, while the influence of pipeline material and soil stiffness is much greater. When the elastic modulus of a pipeline or soil increases, the maximum and differential settlements of pipelines are obviously reduced. This study can be a reference for the future construction of the Hangzhou Metro.

A plane strain model was designed for research according to the similarity theory. Under the consideration of the grouting pressure, the progressive failure characteristics of a subway tunnel foundation with a single karst cave beneath were analyzed. In the experiment, a cylindrical airbag was used to impose a load which simulates the grouting pressure. With the method of step-loading, the changing law of the soil stress and displacement were discussed and the fracture plane was plotted. Furthermore, the ultimate load was obtained.

Earth pressure balanced shield (EPBS) technology is widely used in tunnel construction projects. LanZhou subway line 1, as the first underground rail transit project, is a typical EPBS construction project in soft clay with gravel. This tunnel crosses the city center from east to west, and its total length is about 34 km, including 24 subway stations. The line 1 project is constructed in soft soil (loess powder soil and silty clay) and fractured formation (sand gravel layer and conglomerate). One ZTE6410 earth pressure-balanced shield machine was used to construct this tunnel. However, tunneling in soft soil and fractured formation poses various challenges. including the risk of a massive rush of groundwater and ground deformation. This paper provides an overview of this project and summarizes the challenges faced and the techniques used to handle the difficulties encountered during construction.

Pipe jacking construction produces disturbance to the original formation, causing soil mass deformation and ground subsidence. Based on municipal sewage pipeline engineering in Xi'an, the process of pipe jacking construction was simulated by using the three-dimensional finite element method. In particular, the ground deformation caused by the construction disturbance was researched. The results showed that the deformation of soil is mainly distributed in the departure area and pipe jacking pressure surface. The size and distribution of the plastic zone of soil around the segment was analyzed, and the numerical simulation results and field test results are consistent. At the same time, in order to control the settlement of formation, the large plastic deformation area should have grouting reinforcement. The results have provided theoretical guidance for the safety of the pipe jacking construction.

In this paper, the tunnel face stability is studied by investigating the stress release on the tunnel face. The ultimate stress release rate, the pattern of the failure mechanism and displacement obtained are discussed in detail. The support pressure assumed to resist the earth pressure is introduced and a comparative study was made with the results of the centrifuge model tests by Chambon (1994). The influence of diameter D and cover depth ratio C/D on ultimate stress release rate and support pressure are also given.

There are many different kinds of cross-section structure forms in the rectangular immersed tube and their stress distributions are complex. In order to confirm the rectangular immersed tube structure features, the finite element software ANSYS is used to analyze the characteristics of the force in the immersed tube structure under different settlement conditions combining specific geological conditions and engineering design requirements. The worst tension parts of the immersed tube are the inner side of the lane floor and the lower side on the outside of the side wall. Chamfer or fillet could be set inside the base lining turning points to reduce stress concentration levels. Combined with tensile stress directions, this paper puts forward feasible suggestions on the structure of the internal reinforcement layout.

Monitoring the productivity of trenchless construction processes, such as Pilot Tube Microtunneling (PTMT) installations, is necessary for proactive control of construction operations. For example, engineers can correlate construction operation parameters (e.g., forces) with contextual information (e.g., soil type) for identifying factors influencing the PTMT productivity. Awareness of these correlations can help engineers select and control the equipment accordingly. Such correlations, however, are hidden in large amounts of field data. Tedious manual data collection and processing cannot capture and analyze details of PTMT workflows. This paper presents an automated data collection and interpretation approach for supporting detailed PTMT productivity analysis. This approach uses a data logger to automatically record the hydraulic pressures of equipment used during the PTMT. A two-step pattern recognition method can detect time-series patterns of the hydraulic pressure and identify cycles of operation in three stages of the PTMT:(1) pilot tube installation; (2) casing installation; and, (3) product pipe installation. The first step uses an Artificial Neural Network (ANN) to classify the time-series as belonging to a certain stage of PTMT. The second step uses an Adaptive Anomaly Detection Algorithm (AADA) to split the time-series into sections corresponding to operational cycles. A case study demonstrates that this automated approach can reliably recognize operational cycles of construction equipment in PTMT workflows.

Through a two-dimensional, finite element numerical method, and with the help of Plaxis software, a shield tunnel of power cable driving under the existing railway line was simulated. To protect the railway from the excessive subsidence caused by tunneling, the effects of three grouting reinforcement schemes, differing in grouting range, were analyzed. Scheme I reinforced soils above the tunnel, scheme II was half-section reinforcement, and scheme III was full-section reinforcement. The results showed that all three schemes could meet the requirement of subsidence control. However, compared with the two other schemes. scheme III had engineering feasibility, could help reduce bending moment of the segment, and would benefit the long-term stability of tunnels. In all, the full-section reinforcement was recommended.

Pulling loads is an important parameter of oil and gas pipeline crossing projects using horizontal directional drilling. Predecessors in the establishment of pulling loads calculation model that are mostly derived from theoretical analysis, replace the ideas here, and from the perspective of data analysis established the pulling loads calculation model of different strata. Results are compared through specific project cases. From the comparison of the results of the data analysis method, norm method and actual maximum pulling loads, it can be concluded that the model from the data analysis method can be used to predict pulling loads of oil and gas pipeline crossing projects using the horizontal directional drilling.

Wellbore instability is often encountered in horizontal directional drilling projects. Not only does it seriously influence the normal progress, but it also causes huge loss of manpower, material and financial resources. In this paper, the relationship between pullback speed and wellbore stability has been systematically studied based on the project's pullback data of the China Petroleum Pipeline Bureau. Finally, a fluid-solid coupling simulation analysis was made by use of the ABAQUS finite element software. By analyzing the several key factors of the impacts of pullback speed and strata on wellbore stability, it is concluded that appropriate pullback speed is a basic condition for ensuring the stability of wellbore. The results have certain reference significance for construction.

The 2nd phase Project of Feed Pipelines Expansion in Xi'an City, China is the key program for urban construction in 2011 for Shaanxi Province. The to-be-expanded pipelines are also the main ones supplying water for Xi'an International Horticultural Expo, which has attracted high attention from municipal leaders and all sectors of society. The directional drilling project (2,270 m long with a steel pipe specification of Φ1220mm × 14mm) is located at Dongyue Road of C section affiliated to the expansion is the most difficult one and determines the whole program. In this paper, discussions and summaries are made for key technologies and techniques on non-excavating horizontal directional drilling based on project practices so as to provide reference for similar projects.

This article describes how Tieling City in directional drilling Chaihe ends the case that is out of the soil layer of gravel across the circle to take measures to ensure the successful implementation of technology solutions for directional drilling. According to natural conditions through pipelines across the region and the formation of geological survey data, the experience of previous works reasonably determines the technical program and the types of adverse geological directional drilling crossing of great reference value.

A trenchless pipeline HDD crossing is a key project of oil and gas pipeline construction. Although technology is relatively mature, with the requirements of larger diameter, longer crossing span and much more complex geological conditions, a lot of problems have emerged in the design and construction process. Thus, failure of project cases are markedly increased and will eventually result in great loss. Currently, a long distance, large diameter HDD crossing in complex geological conditions has many key issues. This article analyzes the HDD technology status and existing problems in China. It discusses the design and construction ideas and development direction in the future for HDD, utilizing the aided design tools, improved design and construction quality to guide the smooth implementation of HDD construction.

The impacts of adverse geological conditions in the Qinghe River on directional drilling constructionare analyzed. By analysis and comparison of various common river crossing methods, the superiority of the directional drilling method is shown. A directional drilling construction design and constructive role for the future of similar geological conditions are proposed.

Pipeline coating is prone to being destroyed by sharp gravel when going through stone soil without any particular protection. An epoxy glass fiber-reinforced plastics coating has been used to protect the anti-corrosive coating. It is an advanced technology which has been greatly used in foreign countries.

Based on the renewal project of drainage pipes from South Wenling Road (Chengdiao) to Baozhou Road (Tian'an crossing) in Quanzhou City, the rehabilitation method of UV CIPP was analyzed. Consideration of the impact of moving from temporary drainage to a whole drainage system must be taken. Reasonable plans of water plugging and transferring must be chosen. Pipe pre-processing is the key point. Operable processing schemes should be chosen according to different imperfection types. Attention should be paid to summarizing pre-processing methods, developing pre-processing devices and improving the system of pre-processing technology. Additionally, a quality control system of UV CIPP rehab technology should be completed based on pipe condition and experience in China.