Geo-Congress 2019: Data, Software, Education, and a Tribute to Ralph Peck

The geotechnical community is challenged daily with collection, interpretation, transmission, and storage of data as we complete projects involving soil structure interaction. Historic compilation of data requires significant redundancy of data entry and manipulation. Studies have shown that just the collection of test boring data can require up to 11 repetitive data entry steps; each posing a chance for erroneous data entry. Add to this, manipulation for presentation, data entry into analysis programs, and transmission of data to the end client for storage. Again, there are numerous opportunities for error. Like other industries, Cloud-based storage, industrial Internet of things (IIoT) integrated with automated geotechnical instrumentation, common schema (DIGGS), API calls, etc., will be and are impacting the shape of our industry. This paper will summarize the data challenge facing our industry including subsurface exploration, instrumentation, soils structural interaction modeling, etc., and utilize several case histories to demonstrate state of the practice examples of improved data handling, automated input into analysis packages, and efficient archival storage methods that are revolutionizing the geotechnical industry. Realizing and meeting the challenges of older comma-delimited formats, the value of ready transfer of information, and the importance of long-term recoverable storage will continue to drive changes in our industry.

The State of Qatar is in a period of rapid development, modernization, and population growth. One of the most important factors influencing the long-term success and sustainability of future development is a comprehensive understanding of the region’s geologic regime, geotechnical conditions, natural resources, and environmental constraints. To obtain this understanding, the Ministry of Municipality and Environment (MME) of the State of Qatar has undertaken the Qatar Geological Mapping Project (QGMP). The project was developed with strategic foresight to compile and utilize existing subsurface data collected as part of its massive infrastructure and development projects. Recently, the MME, in consultation with Gannett Fleming Inc. (GF) and the United States Geological Survey (USGS) concluded the data collection and analysis phase (Phase I) of the two-phase QGMP. Phase I included: the development of a comprehensive geotechnical relational database (GRDB) populated with data digitized from more than 13,000 subsurface data logs; a detailed data quality analysis and distribution assessment; an extensive gap analysis and needs assessment; and careful design of the geologic mapping and subsurface investigation programs for the next phase of the project. The comprehensive GRDB will allow the MME, other government agencies, and their representatives, the ability to quickly search, query, and assess available geological and geotechnical data for use in site evaluations, project planning, and decision making.

A web-based geotechnical geographic information system (GeoGIS) was developed and tested for the Alabama Department of Transportation (ALDOT). This web-based system stores geotechnical information about transportation projects, such as subsurface data, construction drawings, and design information. Historically this information has been in a digital or paper report or plan sheet format and has been stored at multiple physical locations based on data ownership. The objective of this work was to provide a single enterprise-wide data management system for easy upload, display, and storage of all geotechnical and subsurface structural information from across a state. In addition to reports and plan sheets, GeoGIS can accept, validate, store, and display geotechnical data in the data interchange for geotechnical and geoenvironmental specialists (DIGGS) extensible markup language (XML) format. To facilitate retrieving data, geotechnical information is divided into preconstruction and construction categories that are further divided into specific data or document types, for example: foundation report or DIGGS Atterberg limits test results. Access through a secure web interface allows external consultants and internal ALDOT engineers the ability to upload data and documents and access information by keyword searches and interactive map selection. The web-based GeoGIS maps geotechnical projects that can be displayed on street map or aerial view. Currently, GeoGIS stores over 10,000 geotechnical data and document files associated with over 2,500 projects from across the State of Alabama.

Column-supported embankments (CSEs), with or without a geosynthetic-reinforced load transfer platform, are used in fill scenarios over soft soils to prevent excessive settlement and/or damage to adjacent in-service facilities. CSEs transfer embankment loads to an array of columns as arching mechanisms develop above and below the foundation subgrade level. Load-transfer mechanisms, including mobilization of shear strength in the soil and engagement of geosynthetics in the lower embankment fill, develop as differential settlement between the stiff columns and soft foundation material occurs at the base of the embankment. The load displacement compatibility (LDC) method offers designers the ability to simultaneously couple these load transfer mechanisms and quickly explore the influence of design assumptions (e.g. column spacing, soil compressibility, geosynthetic stiffness, etc.) on load distribution and deformations. The LDC method is publically-available in the spreadsheet “GeogridBridge,” and requires input parameters that are typically estimated during site investigation and construction over soft ground. In contrast to other methods which neglect subsoil support entirely or include subsoil support via a modulus of subgrade reaction, the method employs 1-D consolidation of the subsoil between columns and captures the downdrag of the subsoil on the columns. This paper compares published field measurements and numerical modeling of vertical stress, geogrid strain, and subsoil settlement with computed LDC results from two case histories: one in China and one in the United States. The LDC method shows good agreement with stress measurements, geogrid strain, and subsoil settlement from the case histories with significantly less computational time and expense than numerical methods.

Geotechnical engineering faculty at Drexel University and Villanova University collaborated with local geologists to develop a field trip for their engineering geology courses. The intention of the courses is to have students understand how geology relates to their other courses and careers as engineers. The field trip focused on the core elements of the courses: the importance of rock type on engineering properties, the effects of plate tectonics and weathering on rocks, and the interaction of humans with the lithosphere and hydrosphere. The team selected Wissahickon Valley Park as the location for the field trip because it provides a major stream ecosystem in a geologically diverse setting that has been highly impacted by development of the surrounding city of Philadelphia. The engineering aspects bring novelty into an established practice of classical geology field trips. Based on survey data from the first offering, the students indicated the trip improved their learning experience, reinforced basic geology concepts, and increased their understanding of the relevance of geology to civil, architectural, and environmental engineering.

As geotechnical engineers progress in their careers they are called upon, at an ever-increasing frequency, to provide engineering judgement. In this paper the issue is explored as to how an engineer should address their ongoing learning to acquire the skills and experience necessary to provide these insights. Specific project examples are used to illustrate the differences between applying engineering methods by rote, as opposed to evaluating data obtained to derive safe, appropriate, and economic design solutions.

This paper presents a case study of a 28-foot high retaining wall located on the Rose-Hulman Institute of Technology (RHIT) campus. In addition, the paper provides discussion regarding how the retaining structure is used to enhance student learning. The wall consists of soldier piles and wood lagging with 27 permanent tiebacks (22 are HP12x53 and 5 are HP14x73), and the tieback lengths vary from 22.5 to 40 feet. Wall construction was completed in 2017. Instrumentation, including load cells, inclinometers, and water level indicators were installed during construction to measure deflection, tieback load, and water level data during and after construction. This paper presents a description of the construction activities and the data gathered to date. It also presents student experiences of dealing with a full-scale structure to provide practical, hands-on learning regarding retaining structures. These experiences indicate that the project can potentially arise more interest and give motivation to study the topic. Finally, the paper presents lessons learned from developing a full-scale structure into a living laboratory that can be used directly in geotechnical and structural engineering courses.

The number of women in the geotechnical engineering profession has increased exponentially in the past 30 years. Even so, women only comprise about 20% of the geotechnical faculty in the U.S. This case study describes a recent project to create an enduring network of geotechnical engineering faculty colleagues and collaborators, both women and men. The authors implemented a professional development intervention model to improve networks and collaboration and a social network survey to improve understanding of existing networks and practices. Within the intervention model, a successful strategy for establishing new collaborations and enhancing existing collaborations, was the award of small seed grants combined with the structured opportunities to meet and learn together. The seed grant program could be a model for academic institutions and other organizations to facilitate collaborative efforts that could lead to greater research funding and faculty inclusion on larger, interdisciplinary proposals solving the complex problems of today.

This paper highlights an effort to address the lack of exposure to field testing and practical experience in geotechnical engineering education through the development and implementation of a mixed reality and mobile (MR&M) educational game, “Geo Explorer.” In the spring 2017 semester, a course module was implemented in existing geotechnical engineering courses on a campus other than that of the developers (off-site). The formative evaluation of the module was designed to ensure that the game addressed the module’s learning outcomes and measured student learning. Pre-game and post-game implementation surveys were conducted. The classroom implementation included a pre-game survey, which included technical questions designed to evaluate their learning. Then the students received a traditional lecture to teach cone penetration testing (CPT) procedures and analysis. This was followed by introducing the CPT portion of the GeoExplorer game to the class, which started with the same technical questions. After completing the game assignment, the students completed the post-game survey. Preliminary results show a one point gain in student confidence after playing the game (from slightly to moderately confident on a likert scale) and an increase in correct content knowledge responses from 13% to 67%.

The site where the Tangguh liquefied natural gas (LNG) plant was to be developed was one of the most remote locations on earth, on an island in Indonesia about 2900 km (1800 miles) from the nearest soil testing laboratory. Results from tests performed in that laboratory were found to be of very poor quality and unusable for design. Starting over with new samples and new tests would have added many months to the time line for development of the project. In addition, it would have been necessary to establish what groundwater conditions would develop during the heavy rainfalls that could occur in the area, and what factor of safety was appropriate for design of this critically important facility. Fortunately, an excellent topographic and geomorphological study had been performed by Baynes. These studies showed that silty to clayey soil blanketed the hilly site where the plant was to be developed. It was evident that the topography of the area had developed over thousands of years through natural processes and could be relied on to indicate what slopes would be stable in the area over a long period of time. In view of the difficulties involved in using a conventional approach to design, it was decided to use the observational method to establish soil strength parameter values, groundwater levels, and factors of safety for design: soil strength parameters were evaluated using back analysis of the existing hill slopes that contained relic landslides. Failure of an over-steepened excavated slope that occurred during construction showed that these strengths were reliable; groundwater levels during extreme rainfall conditions were assumed to be at the ground surface, and this high groundwater condition was found to be consistent with the back-analysis results; it was concluded that a factor of safety equal to 1.0 could be used for slopes designed using the back-calculated strengths, on the basis that the natural slopes must have already experienced the extreme conditions characteristic of the site. This paper describes the methods used and the results of the observational method studies.

To mark fifty years of the observational method in Professor Peck's Rankine lecture in 1969, this paper summarizes two case histories where the observational method played a key role in helping make decisions for the future operation of large civil engineering constructions. For the CDP1 gravity base platform on the Frigg Field in the North Sea, the use of the observational method with measurements and new stability analyses enabled the stakeholders to make a decision on the conditions for safe operation of this oil and gas production platform. Eight additional production years were made possible. For the Zelazny Most tailings dam in Poland, in situ measurements followed (and continue to follow) the movements of the dam during operation. The use of the observational method resulted in design changes, including the moving of the dam crest, the construction of stabilizing berms, and the installation of relief wells in the foundation. The paper also suggests to complement the observational method with Bayesian updating.

Whitehouse Lake Dam is a 15.2-m (50-ft) tall earth fill dam located in Smith County, Texas, near the small community of Whitehouse. The dam is owned by the nearby City of Tyler, Texas, and is a primary source of water supply for the city. The dam was constructed in 1948–1949. During a routine site visit in June 2012 to observe some undermining of the concrete spillway, significant seepage was observed on the downstream toe area of the dam, with indications of critical internal erosional piping that could potentially put the dam at risk of failure. A design team was quickly formed and began interactions with the Texas Commission on Environmental Quality–Dam Safety Program. An extensive site exploration was conducted, and instrumentation was installed and monitored frequently during the design of remedial measures. The site exploration and instrumentation confirmed the internal erosional piping. Extensive analyses were performed including finite element seepage analyses and 2D and 3D slope stability analyses. A soil-cement-bentonite (SCB) cutoff wall approximately 915 m (3,000 feet) long and up to 25 m (80 feet) deep was designed to reduce the seepage, along with repairs to the spillway and compaction grouting of critical areas. Construction was completed in early 2015 at a cost of approximately $8 million. The repairs resulted in a large reduction of the seepage to very acceptable levels. Continued monitoring of the instrumentation indicates that the safety issues related to the seepage have been fully remediated. The observational method was used throughout this project.

The importance of case histories to our understanding of the performance of municipal solid waste (MSW) landfills subject to seismic shaking is irrefutable. Case histories have been used to establish the properties of MSW at large cyclic strains, that earthquake ground motions may be amplified by MSW landfills in a manner similar to amplification of earthquake motions by earth dams, and that, despite the potential for significant amplification, the waste mass in an unlined landfill is able to withstand very high levels of seismic loading without instability or large deformation. However, case histories have also shown that geomembrane liners for landfills may be susceptible to damage when subject to strong ground motions, that the allowable nominal tensile strain in a geomembrane may be limited due to installation damage and strain concentrations, and that sampling of geomembrane seams for CQA testing should be avoided where tensile strains are expected, including on the upper reaches and bench of a lined slope.