68th Annual Geotechnical Engineering Conference
<< February 27, 2020 >>
In conjunction with: Geo-Congress 2020, February 25-28, 2020
*ABOUT THE CONFERENCE/CONGRESS
Full registration for Geo-Congress 2020 will provide the opportunity to attend all podium and poster sessions highlighting over 400 peer reviewed technical papers, five signature lectures, conference plenary sessions, technical committee meetings, and several other activities and networking events. This is a once-in-a-career opportunity to attend our annual conference and an international congress. There are several pre-conference workshops and short courses (short courses require an additional fee), a student program, large exhibitor space, and over 35 curated special sessions with featured presentations from research, consulting, industry, and government. Highlighted partner organizations include the US Army Corps of Engineers, TRB, FHWA, NRRA, and the Canadian Geotechnical Society.
Participants of the 65th, 66th, or 67th Annual UMN Conference can obtain a discount code that applies a discount of $100 to the Full registration rate (not to already discounted Speaker/Moderator, Student, 1-Day, or Government rates).
Participants of the 65th, 66th, or 67th Annual UMN Conference should write to email@example.com and indicate the conference number, either 65, 66, or 67, so we can check our records; provide a mailing address for the proceedings. Place “discount code” in the subject line.
The Early Bird registration is good through December 11, 2019. Note also that there is a Flex Registration available where four organizational badges, which can be shared among multiple people, is an option for those who may not be available to attend the entire conference: https://www.geocongress. org/flex-registration
Please join us for an evening of networking, food & drink, and a keynote lecture delivered by a world-renowned professor in the geotechnical community!
MGS-GI and ASCE-MN jointly present the Geo-Banquet (Dinner & Lecture), held in conjunction with Geo-Congress 2020, on Wednesday, February 26th, at the locally acclaimed McNamara Alumni Center on the University of Minnesota campus. Following a networking cocktail hour sponsored by Hayward Baker, and plated meals catered by D'Amico & Sons, Professor Lyesse Laloui, from the Swiss Federal Institute of Technology Lausanne (EPFL), will present "Tailor-made soil properties with novel bio-geo-chemical means."
The Proceedings of the University of Minnesota 68th Annual Geotechnical Engineering Conference will be complimentary to Geo-Congress registrants who use the discount code. Provide a mailing address for the proceedings when writing for the discount code. The UMN proceedings will also be included as part of the overall (e-version) Geo-Congress 2020 Proceedings.
8:15 A.M. Kersten Lecture Energy Geotechnology: A New Era for Geotechnical Engineering Practice Lyesse Laloui Professor, Laboratory of Soil Mechanics Swiss Federal Institute of Technology Lausanne (EPFL), Switzerland
Energy geotechnology provides low carbon, cost-effective and local energy solutions to structures and infrastructures, which opens a new era for geotechnical engineering practice, by extending the conventional role of structural design to that of addressing acute energy challenges of our century. This paper reviews the methodology behind energy geotechnology by highlighting its scope and applications to various geostructures for structural support and energy supply of built environments. Aspects of primary importance for maximizing the energy, geotechnical, and structural performance of energy geostructures and solutions to address this challenge are presented. Moreover, analytical solutions and design tools, as well as performance-based design of energy geostructures are introduced. The goal of this paper is to uncover the potential of energy geotechnology on the path of less dependency on fossil fuels and to emphasize the critical role of geotechnical engineers to take full advantage of this technology.
9:15 A.M. The Art of Numerical Modeling in Geomechanics Peter A. Cundall Adjunct Professor, Civil, Environmental, and Geo- Engineering University of Minnesota, Twin Cities
Numerical modeling is used extensively in the design and evaluation of projects that involve the behavior of rock, soil, and groundwater. There are many potential pitfalls for the modeler, particularly if inexperienced, some of which are discussed. The importance of understanding mechanisms is stressed, and this point is illustrated with examples that show the advantages of building simplified models in addition to detailed models for site analysis.
10:00 A.M. Break
10:30 A.M. Lessons (Re)learned from Geotechnical Failures Richard J. Finno, P.E., D.GE, Life Member ASCE Professor Emeritus, Civil and Environmental Engineering Northwestern University, Evanston, IL
Despite the advances in knowledge in geotechnical engineering over the last decades, failures during construction of structures still occur. This paper describes four such failures related to excavation support, and discusses their causes, from both technical and non-technical standpoints. The failures described include both limit and serviceability state failures. One can expand the notion of redundancy to include non-technical issues and it is in this context that the failures are discussed. The case histories show that if redundancy had been properly employed during design and construction, the failures probably would not have occurred.
11:15 A.M. Twenty-Year Performance of a Mixed LLRW/RCRA Waste Disposal Facility Rudolph Bonaparte, Ph.D., P.E., D.GE, F.ASCE Senior Principal Engineer Geosyntec Consultants, Atlanta, GA
A mixed low-level radioactive waste (LLRW) and Resource Conservation and Recovery Act (RCRA) waste on-site disposal facility (OSDF) was constructed as part of the remediation of the U.S. Department of Energy Feed Material Production Center in Fernald, Ohio. The 56-acre (lined area) OSDF is fully constructed, filled with waste, and closed. The facility was operated from November 1997 until October 2006, with operational data available from January 2000 to the present, a period of nearly 20 years. Post-closure monitoring is ongoing. This paper presents the design, construction, and performance of the OSDF, with a primary focus on its operational performance. Available performance data for the OSDF’s leachate collection system, leakage detection system, and horizontal-well vadose zone monitoring system are presented and evaluated. Observations from post-closure monitoring of the OSDF are described. The data and information indicate that the OSDF is performing well and is not impacting groundwater or surface water at the site.
12:00 noon Lunch
1:30 P.M. Concurrent Session 1A Gas Explosion Analysis Otto D.L. Strack Professor, Civil, Environmental, and Geo- Engineering University of Minnesota, Twin Cities
We present the analysis carried out to investigate the cause of a gas explosion that occurred in Minneapolis. A gas pipeline leaked, resulting in the explosion, and the objective of the analysis is to determine whether the leak resulted from failure of a water main existing below the pipeline, or from differential settlements causing the failure of couplers that connected sections of the pipeline. An analysis based on the theory for a beam on an elastic foundation makes the differential settlements the most likely cause of the explosion. Concurrent Session 1B The Use of Steel Pile as Permanent Building Foundation Walls: Lessons Learned over 15 years of Design in Minneapolis, Minnesota USA Chad A. Underwood, P.E., P.G., D.GE, M.ASCE Principal,Engineering Partners International LLC, Eagan, MN
Design of several projects in the Twin Cities area will be reviewed, where steel sheet pile walls have been used as permanent perimeter foundations to support buildings with one to three levels of below grade parking and up to 16 above grade floor levels. Similar to conventional foundation walls, the sheet pile walls provide lateral support for soil and surcharge loads, and vertical support for below grade parking slabs and perimeter walls and columns of the superstructure. Also included will be results of dynamic tests completed on sheet pile using a pile driving analyzer.
1:52 P.M. Concurrent Session 2A Quo Vadis? Inakeyaa! Inferring flow direction using a Bayesian approach Randal J. Barnes Associate Professor, Civil, Environmental, and Geo- Engineering University of Minnesota, Twin Cities
Before we build a predictive groundwater flow model, we first identify candidate conceptual models. To cull our collection of candidate models, we ask the seemingly simple but key question: Where is the water coming from? A Bayesian framework can be used to address this question. We start with an uninformed prior distribution that suggests all directions are equally likely. We then incorporate the available information and appropriately update the characterization of the uncertain direction. When the added information is extensive and internally consistent, a clear flow direction emerges. On the other hand, if the added information is minimal or internally inconsistent, the uninformed prior is only slightly modified. Concurrent Session 2B Supporting a Bridge Between Countries Case Study: Construction of Baudette Bridge Drilled Shafts Nathan W Iverson, P.E. Chief Geotechnical Engineer, Foundation Division Veit and Companies, Rogers, MN
Minnesota Department of Transportation and the Ontario Ministry of Transportation started construction of a new border crossing to replace the existing historic bridge in Baudette, MN. The new bridge was designed to bear on drilled shafts instead of driven pile like the adjacent railroad bridge and previously constructed bridge. The bridge design includes four river piers supported on 2.4 m diameter drilled shafts up to 30 m below river elevation. Piers one and two are located on the US side of the river and piers three and four are located on the Canadian side. The piers were constructed in the existing river from barges. This case study details the shaft design, bi-directional testing, concrete design and production, thermal integrity profiler results, obstructions, drilling techniques, clean out procedures, and a dynamic working environment in an extreme northern climate.
2:15 P.M. Concurrent Session 3A Computational Tools for the Analysis of Stability of Embankments in Frictional- Cohesive Soils David Saftner, P.E. Associate Professor, Civil Engineering University of Minnesota, Duluth
This paper presents a series of computational tools for quick estimates of factors of safety and critical circular failure surface locations for embankments. Cases of a firm horizon that the failure surface cannot cut through are considered to exist at the base of the embankment or at great depth. The latter case corresponds to the case of a slope in homogeneous soil. Dimensionless functions defining the factor of safety and position of the critical failure surface are constructed using the Bishop method of slices in a commercial limit equilibrium software. Results are implemented in a spreadsheet that is available for downloading. Formulas for evaluation of factors of safety are also presented. The effect of the cohesion and friction angle of the soil and the position of the firm horizon on the resulting factors of safety and depth of the failure surface are discussed. An example solved with the proposed tools and with the shear strength reduction technique is presented. Concurrent Session 3B Eisenhower Bridge North Abutment and Approach Settlement: A Case History or Timber Pile Downdrag and Comparative Downdrag Effect on Steel Piles Steven J. Olson, P.E., M.ASCE Senior Geotechnical Engineer HDR Engineering, Inc., Minneapolis, MN
The north abutment and approach of the Eisenhower Bridge has settled significantly since completion in 1960 and is currently several feet lower as compared to the 1960 construction plan profile. The north approach originally consisted of a 7.6 m-high embankment placed on a soil profile of loose/ soft alluvial sands, silts, and clays (alluvium) underlain by a very dense layer of sands and gravels; the north abutment was supported by 26 timber piles driven through the embankment fill and alluvium to practical refusal bearing on very dense sands and gravels. As the approach embankment adjacent to the abutment settled from consolidation of the soft alluvium, drag load developed on the timber piles and induced excessive internal stress and end bearing pressure on the piles. It is believed the yield strength of the timber piles was exceeded, resulting in damaged or broken piles. The purpose of this study is to demonstrate how the drag loads on the timber pile system caused excessive stress and movement of the abutment and provide comparative analyses with steel piles.
2:38 P.M. Concurrent Session 4A Experimental Study of Forces Induced in Mechanical Excavation of Rock John Pultorak Research Assistant, Civil, Environmental, and Geo- Engineering University of Minnesota, Twin Cities
This paper presents preliminary results of an experimental campaign aimed at mapping the dependence of the cutting force on the depth of cut in scratch tests performed with a sharp cutter. Tests conducted in Berea sandstone and Indiana limestone confirm that the scaling of the force with the depth of cut depends on the cutting regime. They also show a dependence of the nature of the frequency distribution of the cutting force on the modes of failure. Concurrent Session 4B Kennedy Bridge Instrumentation: A Pier Review James C. Bennett, P.E., LEED AP, M.ASCE Associate Principal – Project Engineer Braun Intertec Corporation, Minneapolis, MN
This presentation is about the historic Kennedy Bridge, which conveys US Highway 2 between East Grand Forks, MN and Grand Forks, ND. Specifically, it is about one of its piers and the instrumentation system adorning it and the surrounding soils. The sensors were designed and installed to endure the most extreme environments and recount an uninterrupted, quarter-century long story of infrastructure performance.
3:00 P.M. Break
3:30 P.M. Concurrent Session 5A Washington Park Reservoir Improvements: Accommodating Ancient Landslide Movement with a Compressible Inclusion Thomas Westover, P.E., M.ASCE Associate Engineer Cornforth Consultants, Inc., Portland, OR
The Portland Water Bureau, until recently, had operated two open drinking water reservoirs at Washington Park in Portland, Oregon. The open reservoirs were part of a gravity-fed water system constructed during the 1890s. During original construction at the site, a large ancient landslide was re-activated. A project to improve the reliability and protection for the water supply is currently in progress, and includes a buried 12.4-million gallon (47M liter) concrete reservoir. When completed, the project will provide a seismically resilient supply of drinking water to 360,000 people, including all of downtown Portland. The buried reservoir will be isolated from continued landslide movements using an innovative compressible inclusion, which will deform in response to continued landslide movement, and in turn will impart relatively small, predictable loads on the buried reservoir walls. During a seismic event, the compressible inclusion will absorb landslide displacement as well as dampen reservoir displacements. Concurrent Session 5B A Retrospective on the Evolution of Geotechnical Sensing and Instrumentation for Monitoring at MnDOT Joel N. Swenson, P.E. Senior Geotechnical Engineer Barr Engineering, Minneapolis, MN
The Minnesota Department of Transportation (MnDOT), other transportation asset owners, and geotechnical consultants are embracing sensing and monitoring to add project value and reduce risk. Historically, measurements to assist with field observations of performance have occurred since the 1930s, when engineers relied on hydraulic and mechanical systems to measure field behavior or performance. In the decades since, there have been significant advancements made in communications and computing technologies that have enhanced monitoring capabilities in terms of accuracy, precision, reliability, size, cost, networking, and functionality. With these advances and benefits have also come unexpected challenges and opportunities. A retrospective on geotechnical monitoring at MnDOT, a discussion on technologies for applications today, and thoughts on the future of the geotechnical monitoring practice will be presented.
3:52 P.M. Concurrent Session 6A Detecting Pile Lengths of Sign Structures and High Mast Poles Daniel V. Kennedy Research Assistant, Civil, Environmental, and Geo- Engineering University of Minnesota, Twin Cities
Several hundred high mast light towers throughout the state of Minnesota have foundation systems that are typically concrete-filled steel pipe piles or steel H-piles, with no construction documentation (e.g. pile lengths) and soil stratigraphy information. Reviews of designs within current standards suggest that many of these foundations may have insufficient uplift capacity in the event of peak wind loads. The goal of the project is to establish a non-destructive field testing technique, including data analysis algorithm, for determining in-place pile lengths by way of seismic waves. A unique feature of the proposed work is the use of computational modeling to account for the effects of soil profile and ground conditions (e.g. layering) on the sensitivity of the method. The pile length will be identified through a systematic sensing approach that includes (i) collection and classification of the pertinent foundation designs and soil conditions; (ii) 3D simulation of dynamic soil-foundation interaction; (iii) parametric studies of the 3D pile vibration problem; (iv) field testing, and (v) analysis-driven data interpretation. Concurrent Session 6B An Overview of Performance Monitoring for Drilled Full Displacement Type Rigid Inclusions under Highway Embankments Liang Chern Chow, P.E., M.ASCE Geotechnical Engineer American Engineering Testing, Inc., Saint Paul, MN
Column-supported embankments with rigid inclusions have been popular for many transportation projects that include a combination of rapid timeline, environmental issues, and/or specific subsurface conditions. In traditional embankments built on soft ground, the most frequent uses of instrumentation are to monitor the progress of consolidation and to determine its stability. Conversely, in column-supported embankments, different mechanisms and modes of failure emerge despite minimal consolidation. Thus, the use of instrumentation must be altered to address the anticipated behavior of column-supported embankments to effectively monitor performance. Instrumentation programs for rigid inclusions are not standardized. This paper discusses the overall practices in instrumentation for drilled full displacement type rigid inclusions for both national and international case studies followed by local experience in Minnesota. After 3.5-years of continuous monitoring, the data were reassessed to evaluate the actual soil-structural interaction and the maximum loads acting within several columns.
4:15 P.M. Concurrent Session 7A A Failure Mechanism around Axially Loaded Sockets in Weak Rock Pouyan Asem, Ph.D., A.M.ASCE Post-Doctoral Fellow, Civil, Environmental, and Geo- Engineering University of Minnesota, Twin Cities
This paper is concerned with the failure mechanism predicted from the cylindrical cavity expansion model for a rock mass around the sidewalls of axially loaded sockets. The failure mode, which depends on the initial lateral stresses, load-induced radial stresses, and tensile strength of the rock, is critical to identify so that the axial capacity and stiffness of the foundation can be determined. A comprehensive database of in situ load tests, specifically drilled shaft, anchor and plug load tests in weak rock provides validation of the model. The back-calculated shear stress – shear displacement relationships for socket sidewalls in each load test are used to calculate load-induced radial stresses developed on the socket sidewalls. The tensile strength is obtained from tabulated ratios of uniaxial compressive strength to tensile strength and knowledge of the measured compressive strength. The failure mechanism around the socket sidewalls is analyzed by applying the Fairhurst (parabolic) failure criterion. Theory shows that the rock mass generally fails by circumferential tension, which is in agreement with field observations. Concurrent Session 7B Sky Harbor Airport Runway Realignment Hector D. Flores, P.E. Engineer Short Elliott Hendrickson, Inc., Saint Paul, MN The Duluth (MN) Airport Authority identified several obstructions to a runway approach surface. As a result, the Authority completed a multi-year federal and state assessment to evaluate alternative solutions with respect to the runway approach. The obstructions consisted of old growth trees, the majority of which were located within a protected scientific and natural area. The selected solution consisted of shortening the runway from 0.93 km to 0.79 km and rotating it 5 degrees into Superior Bay. The geotechnical design of the runway considered slope stability and settlement of the embankment fill. Staged preloading of the site was completed using surcharge fill with a geotextile reinforcement base layer to improve stability. In addition to monitoring settlement, drone surveys were completed of the surcharge fill embankment. Underwater surveys were completed to verify the riprap embankment protection dimensions placed in Superior Bay. This case study presents the geotechnical investigation and design of the runway relocation along with results of construction monitoring of fill placement and settlement.
4:38 P.M. Concurrent Session 8A A Review of LRFD Bridge Foundation Design and Construction in South Dakota Brett E. Belzer Project Engineer RESPEC Mining and Energy, Rapid City, SD
Load and Resistance Factor Design (LRFD) is a reliability-based limit state design methodology. In this study we investigate the concept, application, and implementation status of LRFD in shallow and deep foundation designs for the South Dakota Department of Transportation. Challenging the use of LRFD are the frequent occurrence of difficult geologic conditions including expansive soil and rock, deep seated landslides, soft and/or highly weathered shales, intermediary geologic materials, and highly corrosive soils. Whereas deep foundation design parameters are relatively well established for LRFD methods, local calibration of shallow foundation design parameters has not yet been performed in most states. This paper examines the current status of LRFD and discusses its implementation for shallow and deep foundation design in South Dakota and provides a set of recommendations that engineers can consider as they pursue implementation of LRFD on construction projects. Concurrent Session 8B On Solid Ground: Preventative and Responsive Geotechnical and Structural Mitigation of Geologic Hazards Impacting Oil and Gas Production Charles D. Hubbard, P.E., P.G. Principal Braun Intertec Corporation, Minneapolis, MN
Supporting oil and gas production for pads, pipelines, and associated infrastructure is accomplished through a variety of means that include site reconnaissance, exploration and material testing, geotechnical instrumentation and monitoring, analytical modeling, and geotechnical and structural solutions. This paper highlights work performed on sites both pending and in production. The featured sites lie within badlands type terrain host to geologic hazards related primarily to slope instability, which have been mitigated with traditional mass grading, and/or ground improvement, retention, buttressing, and drainage techniques. The intent of this paper is to describe the components of effective site characterization and hazard identification/ qualification programs.
5:00 P.M. Adjournment