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By Melinda J. Hummel, Zachary T. Smith, Nathaniel Witter, Nina F. Carney

The revitalization of Pittsburgh’s historic Strip District has led to the redevelopment of existing properties and the development of new properties. At one time, the Strip was home to wholesale market products. Now, the historical warehouse buildings are being converted to multi-use residential and commercial properties. One such property, 1600 Smallman Street, consisted of 1 to 6-story connected buildings that housed night clubs, retail shops, and office space. The lower story portion of the building, on the southwest side of the property, was torn down to make room for a new 5-story- parking garage with street level retail space. The remaining 6-story-building, on the northeast, was gutted to be renovated into high-end condominiums, keeping the exterior historical building facade.

By A. Daouadji, P. Cazes, S. Grange, L. Briançon, R. Milane

Construction in congested urban areas is often accompanied by geotechnical problems due to high loads and the impact caused by nearby buildings. For this reason, it is important to understand the behavior of the soil and the structure without forgetting the essential role of the interaction between them. Experiments, instrumentation and numerical modeling are the main methods used to study this behavior. To this end, pressure cell, strain gages, vibrating wire extensometers and optical fiber sensors are installed on the reinforcement steel of pile and raft foundations to monitor stresses and induced deformation in these elements during and after construction. A fiberglass rod extensometer is placed in the soil to help measuring the displacement due to excess loading, knowing that the pile foundations are embedded in the Rhône’s alluviums and reach the molasse, a particular and challenging soil with properties that are not yet well understood. The objective of this paper is to present the geotechnical instrumentation program carried out for the tower Silex2 in Lyon, France, and to describe the types of sensors used and their installation on site. INTRODUCTION The complexity of geotechnical structures like dams, bridges or high-rise buildings requires a sound understanding of the behavior of the soil, the structure itself and the interface. Therefore, a geotechnical instrumentation program can be essential in many ways. During the site investigation stage, it can help determine the initial conditions experienced by the soil in the field by measuring parameters such as the compressibility index or the permeability. During the construction stage, real time measurements can protect the structure from premature failure, help validate and optimize the design if needed. In addition, sensors measuring pore-water pressure, loads, deformations and settlements allow for monitoring the performance of the structure. This is called the observational method. Finally, during the operating phase, instrumentation aims to study the long-term behavior of the structure (Nicholson et al., 1999).

Jan 1, 2019

By Satyajit Vaidya, Rudolph Frizzi, Sandy Larimer

"This paper presents a case history in design and construction of a deep foundation system that included high-capacity open-ended driven piles constructed to support a high-rise building in Manhattan, New York. The project site is bordered by existing buildings, active streets, and critical public transportation infrastructure, which were considered in the new building’s deep foundation and seismic design. This paper focuses on driven pile foundation design and installation through relatively loose soil deposits. Unique design aspects included seismic design considerations, and pile splice design for open-ended steel pipe piles subject to significant uplift and lateral loading. Unique construction aspects included quality assurance of open-ended steel pipe pile splices, and uplift and lateral load testing of driven piles installed in close proximity to other foundation elements installed for the project.SITE CONDITIONS AND SUBSURFACE CONDITIONSThe project site is located in Manhattan, New York, and is bordered by existing buildings, active streets, and critical public transportation infrastructure that is located about 60 feet from the site. The existing sidewalk grades around the site are between about el 4 and about el 13; elevations are referenced to the North American Vertical Datum 1988 (NAVD88).Subsurface conditions at the site generally consist of successive strata of historic fill, former river bottom deposits consisting of compressible clayey soils, and medium dense to dense sand, overlying mica schist bedrock. A generalized subsurface profile is shown in Fig. 1. The historic fill stratum is about 10 to 45 feet thick, and generally consists of loose to medium dense sandy soils with varying proportions of silt, gravel, and miscellaneous debris such as brick, concrete, and glass fragments. The underlying former river bottom deposit stratum is up to about 15 to 20 feet thick, and generally consists of very soft to very stiff clay and lenses of very loose to loose sand. Medium dense to dense sand was generally observed below the historic fill and former river bottom deposit strata and overlying bedrock. Top of bedrock was generally observed at about 80 to 105 feet (i.e. at about el -75 to el -100), except in the southeastern portion of the site where the top of rock was observed as deep as about 140 feet (i.e., at about el -135). Groundwater levels typically ranged between about el 1.5 and el -0.5."

Jan 1, 2016

By J. E. De Waele, J. J. Lee, M. J. Mulheron, Luke R. Deamer

There is increasing demand for geotechnical contractors to commit to carbon reduction, net zero or science based targets. A lot of focus has therefore been placed on using low carbon materials and low emission rigs. However, whilst these are ways to help reduce carbon, there is a need to look beyond just substituting materials and fuels to meet net zero. Using the IEMA carbon hierarchy, there is a need to first look at eliminating and reducing emissions, before considering substitute materials. For example, in geotechnical designs, this may mean considering using ground improvement or reducing the number of piles, before considering using low carbon cements. Equally, for remaining emissions, this hierarchy means considering carbon negative products to offset emissions, such as ground source heat pumps. This hierarchy can also be applied throughout geotechnical contractor organisations. For example, considering video conferencing for meetings, before considering public transport or using an electric vehicle. This article explores the carbon hierarchy and how it can be applied to all areas of a geotechnical contractor’s business. Only through embedding this hierarchy across the business can geotechnical contractors achieve the step change required to meet net zero.

May 1, 2022

By Todd W. Armstrong, Michael D. Reader

"INTRODUCTIONThe Playa Vista Development is the largest urban infill development in the history of the United States. Overall, it encompasses about 1100 acres in the City of Los Angeles and is situated north of Los Angeles International Airport near the Pacific Ocean. The development taking place on the project consists primarily of high-density residential condominiums with 1 to 2 levels of subterranean parking . The geotechnical conditions are typified by high groundwater, soft clays, and liquefaction, in addition to environmental issues such as methane.Due to a combination of the geotechnical factors and noise restrictions, both driven and drilled piles were not feasible once the initial phase of the project was occupied. As a result, the project developer undertook a testing program that consisted of the installation and load testing of 9 piles in order to obtain City of Los Angeles acceptance of a pile installation system that met the site constraints. The testing program was divided between two separate contractors operating on sites set on opposite sides on the street (Figure 1 ). Contractors working in Test Areas A & B employed the ""dry dip"" and ""wet dip"" methods of auger pressure grouted displacement (APGD) pile installation, respectively.This paper summarizes the extraordinary program undertaken to install, document, test, and examine auger pressure grouted displacement piles at this site. The program ultimately resulted in City acceptance of auger pressure grouted displacement piles, a historically difficult challenge given the City's resistance of acceptance of ""new"" technologies.A summary of elements included in the test program are: (1) quality control; (2) load testing; (3) long-term testing; (4) non-destructive testing; and (5) pile exhumation."

Jan 1, 2005

By Pirooz Barar

The new Stanley Hall building will house the center for bio-engineering and technology research for the UC Berkeley campus. The structure is located at the northeast part of campus, adjacent to Donner Lab, on the west side of Galey Road, approximately 600 ft. from the Hayward Fault. The building site has a complex geological formation. To the east there are clayey soil shale formations, and to the west there is greywake shattered sandstone. The water table is at 10 ft. below grade. The structure will consist of 6 levels below grade and 8 levels above grade, which calls for an 83 ft. deep excavation on the northeast side. There is an approximately 35 ft. grade differential between the east and west sides of the building. Because of this severe grade differential, as well as high water tables, the lateral forces on the building due to uneven earth pressures would have been 2 times the magnitude of the seismic forces. To mitigate the lateral earth pressures, a permanent Soil Nailed Wall, integrated with the structural system of the building was designed. PB&A, Inc.?s in-house design program ?Winslope? was utilized to design the system and the data obtained from a rigorous monitoring program, were used to calibrate several computer runs using Plaxis program.

Jan 1, 2004

By Sunil Arora, Lisheng Shao, Chris Conkle

"The East Garden Grove - Wintersburg Channel located in Orange County, California, required upgrades along the levees to mitigate potential liquefaction and lateral spreading hazards. The Orange County Public Works designed soilcrete columns constructed between two rows of steel sheet piles along both sides of the channel between Graham Street and Warner Avenue (approximately 2,500 ft), and along an approximately 2,000-ft-long stretch of the south levee. The earthen embankment, approximately 13- to 15-ft high and damaged significantly by erosion, was then excavated to widen the channel to increase the channel flood conveyance capacity.The site is located within the Los Angeles Basin, underlain by several thousand ft of marine sedimentary strata. Uncontrolled fill materials were encountered to approximately 10 ft below ground surface, underlain by tidal and flood plain deposits. Groundwater was encountered at sea level, which is approximately 10 ft below grade.This paper will discuss site soil conditions, and the construction and quality control of soilcrete columns constructed by wet soil mixing; also, the paper will introduce the Drilling Index (DI) as a measurement tool, similar to the cone penetration test (CPT), to evaluate the soil strength in more detail. Finally, the statistical analysis of soil mixing strength distributions for the project quality control will be presented.INTRODUCTIONWintersburg Channel in Orange County, California, required ground improvements along the existing levees to mitigate potential liquefaction and lateral spreading under the site design earthquake. Orange County Public Works designed and developed a cellular pattern of soilcrete columns sandwiched between two rows of steel sheet piles along both sides of the channel between Graham Street and Warner Avenue, and adjacent an approximately 2,000-ft-long stretch of the south levee (Fig. 1). An earthen embankment approximately 13 to 15 ft high, damaged significantly by erosion, was then excavated to widen the channel and increase the channel flood conveyance capacity.Stiff, soilcrete cellular wall structures can reduce the earthquake-induced cyclic shear stress ratio (CSR) in the soil within the cells, thus preventing excess pore water pressure build up which may trigger soil liquefaction. For this project, approximately 6,700 soilcrete columns were constructed in a cellular pattern to an approximate depth of 40 ft. All of the soilcrete columns are 3 ft in diameter with the design unconfined compressive strength (UCS) of 150 psi."

Jan 1, 2015

By Rachael M. Fischer, Daniel J. Woeste, Terence P. Holman

"A new 50 MW biomass renewable energy power plant was planned for construction in southwestern Georgia. The original foundation design consisted of very conservatively designed H-pile groups with vertical and battered piles to carry the axial and lateral loads. The authors conducted a testing program to value-engineer the foundations with the goals of increasing the working axial pile resistance and reducing or eliminating battered piles. Seven test piles were installed and dynamically monitored with a Pile Driving Analyzer (PDA). Two lateral load tests and one tension load test were conducted. The results of our testing program allowed the project team to: (i) increase working pile resistances by factors of 1.5 to 2, reducing the total number of piles by more than 30%, (ii) eliminate the battered piles, and (iii) lessen overall project risk. Poor communication and documentation in a critical area of the site required some piles to be spliced and re-driven after additional PDA testing, establishment of new driving criteria, and consideration of longterm soil setup. This case study emphasizes the economic and risk reduction benefits of a design phase testing program, and the need for consistent communication between parties in the field.INTRODUCTIONA new 50 MW biomass renewable energy power plant (Plant) was planned and constructed in southwestern Georgia. The Plant converts clean wood-based and paper-based waste from existing forestry and pulp operations, waste timber, and maintenance operations into steam that is used by an adjacent manufacturing facility. The Plant also generates electric power with limited greenhouse or particulate emissions for use by a local utility provider.The project site (Site) is located in Dougherty County, in the Coastal Plain physiographic province of Georgia; an area of known karstic activity. Specifically, the Site is underlain at depths of 30 to 45 ft by the Ocala Formation, a light-colored fossiliferous limestone of the Eocene era. According to Watson (1981), the Ocala Formation is 125 to 200 ft thick in the vicinity of the Site and increases in thickness to the southeast. Due to differential weathering, this formation is characterized by an irregular upper surface that transitions from sandy clay/clayey sand into a dense to very dense silt and fine sand locally referred to as limestone. This subsurface stratum is most relevant to the foundation design of the Plant."

Jan 1, 2016

By Venugopal B, M Kumaran, Thomas John, Vetriselvan A

The initial pile load tests are conducted to ensure the geotechnical capacity of the pile in a particular site condition. Normally kentledge method is adopted for the compression pile load tests. In this method the entire kentledge load is loaded above secondary beams which are supported by concrete blocks above the Natural Ground Level. So, it is important to ensure the SBC (for shear and settlement) of the natural ground. In one of our projects initially it was decided to go with kentledge system for initial compression load test on 56m long 1200mm diameter BCIS pile. The test load and total kentledge load were 2160t and 2700t, respectively. The soil strata mainly consisted of clay with low SPT N value and water table almost at ground level. It was suggested to replace top soil using Granular Sub-base (GSB) with good compaction in order to avoid excessive settlement of concrete blocks placed to support the kentledge weight. When the kentledge loading started, even before reaching 10% of total kentledge load, excessive settlement on the GSB layer was observed. This paper describes the problems faced during normal kentledge method and how it was overcome using the liner pile system for initial compression load tests in this particular site condition for higher test load.

Nov 1, 2022

By Terry Eldridge, Keith MacKay, David Siddle, Luke Moger

On August 4th, 2014, a breach occurred in the Perimeter Embankment of the Tailings Storage Facility (TSF) located at the Mount Polley Mine, releasing approximately 10.6 million m3 of supernatant water, 7.3 million m3 of tailings solids, 6.5 million m3 of tailings interstitial water and 0.6 million m3of construction materials. A Temporary Upstream Rockfill Berm was constructed between August 2014 and February 2015 within the area of the tailings dam failure in order to retain the remaining tailings solids during the low flows of the winter season. The Temporary Upstream Rockfill Berm was constructed as part of the initial response phase, with the primary objective to abate the flow of tailings into the receiving environment. A secondary objective of its construction was facilitating the required investigation works downstream of the tailings dam failure. The selection of the coarse grained material used in the construction of the Temporary Upstream Rockfill Berm was based on the availability of the material (timeliness of construction) and the non-water retaining design of this initial response phase. Consequently, an alternative method was required in order to prevent further loss of mine-affected water and tailings from the TSF, as well as to provide short-term contingency water storage, during high flow conditions expected in late spring. Golder Associates Ltd. designed the 2015 Freshet Management Embankment, a deep mixing cut-off wall, to meet these site requirements, which was constructed by Mount Polley Mining Corporation and Golder Construction Inc. between December 2015 and April 2015. The works included 132 soil cement panels constructed to depths of up to 27 meters. This aspect of the works was completed using an RG25S Bauer CSM rig on a 24 hour per day, 7 day per week schedule. The cut-off wall specifications included a target unconfined compressional strength (UCS) of between 1 and 2 MPa, a maximum hydraulic conductivity of 1x10-6 cm/s, and a ductility to enable the soil cement to undergo a minimum of 5% strain without a reduction in strength or increase in hydraulic conductivity. In order to control and assure the quality of the soil cement, 2553 wet grab specimens were retrieved from the fresh soil cement panels using a project-developed sampler. Four of the soil cement panels were cored with a mud-rotary drill rig and optical and acoustic televiewers were placed into the boreholes in order to log several relevant parameters, including image, texture, relative hardness, borehole-shape, and temperature.

Jan 1, 2016

By Gisele R. Passalacqua, Taylor Malangone, Subhash Mahali

New York City is a busy metropolis with 8 million people. New York has the largest public transportation system with 6 million riders a day throughout the subway system. Keeping this infrastructure in service is vital to the overall economy of the region. Hurricane Sandy proved to have a devastating impact on infrastructure in Metropolitan New York. New York City Transit is on the forefront to provide resiliency and maintain its facilities with the use of flood protection systems. This paper presents flood protection structures utilized at Hammels Wye substation site in Far Rockaway, Queens, New York. The site is in close proximity and surrounded by water. The subsurface conditions consist of loose silts overlain by medium dense glacial sand. The high groundwater level combined with limited access to the site presented challenges. A flood protection system consisting of flood walls was recommended for this site. In certain areas the flood walls consisted of retaining walls supported on micropiles. For other areas, the flood walls consisted of steel sheet piles with jet grout columns to reduce seepage below the walls. The effect of driving sheet piles with vibratory hammers on nearby existing structures is always a concern. Recently, hydraulic hammers with variable moment/frequency are being considered as a mean to reduce vibration effects during driving. In this project, an instrumentation testing program was performed to measure peak particle velocity during sheet pile driving utilizing the variable moment vibratory hammer. Plots of peak particle velocity versus frequency were generated. This paper will present the design aspects of the flood walls and construction challenges during installation. This will prove beneficial to engineers in both design and construction fields.

Sep 8, 2021

By Lenin T., Madhav M. R., Padmavathi V.

Use of PVDs and preloading on the ground can significantly reduce the time taken for ground to consolidate. Many soils in situ are lightly overconsolidated, with overconsolidation ratios (OCR) ranging from 1.0 to 2.0 due to various reasons such as glaciation, ground water level fluctuation, aging, cyclic loading, creep, erosion, cementation, etc. The effects of overconsolidation ratio are analysed in this study. Compression index and consolidation coefficient are important parameters in determining time – settlement response of soft soils under preloading and with PVDs. These parameters are typically estimated using oedometer tests on samples, with the assumption that the results represent the entire deposit. The in-situ time-settlement plots at different depths are used in the back analysis for estimating compressibility and consolidation parameters of in situ ground, resulting in more representative values that reflect the deposit's overall behavior. From observed time versus settlements plots, variations of compression index and coefficient of consolidation with depth of a deposit are presented. Estimation of compression index with depth is possible based on different OCR values as shown in this study. Barron (1948), Asaoka methods are used to estimate the coefficient of consolidation with flow in the radial direction.

Sep 1, 2022

By M. Kitazume, H. Imai

The deep mixing method was developed in Japan and put into practice in the middle of 1970s. Since then, the wet and dry type methods have been applied for various improvement purposes in Japan. One stork of mixing tool produces a column shape of stabilized soil in a ground. By the series of productions, arbitrary shape of improved ground can be constructed by overlapping each columns. It is specified to complete the overlapping within 24 hours in order to ensure the tight connection of the columns. However, it can not be completed within the specific time in some cases due to bad weather or machine trouble, which causes a cold joint in the improved ground. In this study, the influence of the cold joint to the behavior of the block type improved ground is examined by a series of centrifuging model tests and FEM analyses. It is found that the ground behavior is influenced by the position of the cold joint, where the cold joint at the sea side shows a little influence to the behavior but one at the port side causes large decrease in the stability of the improved ground.

Sep 8, 2021

By Keith MacKay, John Carter, David Siddle, Fernando Faminia

"The River Green Residential development, is located in the municipality of Richmond, BC adjacent to the Fraser River. Ground conditions at the site consisted of medium to fine grained alluvial sands and a high groundwater elevation. A temporary low permeability retaining wall was required in order to facilitate the construction of an underground parking structure without inducing settlement of adjacent structures, which include the Richmond Olympic Oval; part of the legacy of the Vancouver 2010 Winter Olympics. Golder Associates Ltd. and GeoPacific Consultants Ltd. utilized Cutter Soil Mixing (CSM) technology to enable construction of a continuous combined low permeability cut-off and retaining wall around the perimeter of the property. The 350m long wall was keyed into marine clay at a depth of 28m below ground surface, and contained H-Pile reinforcement installed at regular intervals. The CSM technology provided many benefits for this project, allowing the combined cut-off and retaining wall to be constructed within a very narrow footprint (650mm width). The low noise impact and near vibration free construction of the CSM equipment provided minimal inconvenience to nearby stakeholders during construction. To reduce dewatering volumes during excavation and prevent significant water-table drawdown the Hydraulic Conductivity requirements for the wall were 1 x 10-7 cm/s or less. Project specifications called for a different strength requirement for upper and lower portions of the wall. The top 13 meters of the wall required an Unconfined Compressive Strength (UCS) of 4MPa to act as a retaining and cut-off wall, whereas the bottom 15 meters of the wall required a UCS of only 0.5 MPa to act only as a cut-off wall. Wet-grab and core samples were obtained from the panels to confirm the UCS and Hydraulic Conductivity specifications were met.INTRODUCTIONGolder Construction Inc. and GeoPacific Consultants Ltd. conducted the design and construction of a deep soil mixed cut-off and retaining wall system. The “dry-box” solution was used to surround the excavation of an underground parkade and prevent flows of groundwater into the excavation."

Jan 1, 2016

By Fredrik Sarvell, Harald. Ihler, Veli-Matti Uotinen, Jukka Rantala

"Many of the valid international building codes state that the lateral support provided by the soil is sufficient to prevent buckling of fully embedded piles. However, the development of small diameter micropiles and especially the use of high strength steel have evolved to applications including high capacity elements. The ultimate structural load bearing capacity of a pile in a cohesive soil is decided by examining which gives the lowest value, the peak buckling load and the resisting moment provided by the surrounding soil medium or the structural capacity of the pile cross section. In both cases, the initial deflection of the pile is a significant factor when the axial load bearing capacity of the pile is determined. Steel micropiles are joined commonly with mechanical splices. A less rigid mechanical splice is often a weaker hinge that allows the pile to bend and deflect more during installation increasing the initial deflection of a pile. In addition the less rigid splice element decreases the bending capacity of a jointed pile section and the ultimate axial load capacity of the entire pile. A series of FE analysis performed for various pile sizes suggest that the steel pipe piles including separate pile sections and mechanical splicing elements should have the combined bending stiffness of EIshaft = 0,75 × EIpile. This requirement yields to the buckling resistance of at least 96 % of the solid reference pile with the sameinitial eccentricity in similar soil conditions.IntroductionMany of the valid international building codes state that the lateral support provided by the soil is sufficient to prevent buckling of fully embedded piles. However, the development of small diameter micropiles and especially the use of high strength steel have evolved to applications including high capacity elements. The potential buckling of these very slender high capacity piles in soft soils may in many cases be the controlling design factor of the pile, especially with end bearing micropiles.A typical sequence of soil strata in Nordic countries, such as Norway, Finland and Sweden, constitutes of friction soil or dry crust clay on top of soft clay followed by till. This soil stratum often rests on solid bedrock of granite or gneiss. Conditions like these are suitable for slender end bearing piles subjected to buckling and especially steel pipe piles where most of the material is located at the edge of the cross section. Other reasons for using slender steel pipe piles are for example fast installation with minimal waste, efficient manufacturing and relatively well established design and execution procedures. Minimum quality criteria’s regarding splices for steel pipe piles are recommended to be set as national provisions to ensure quality and comparable procurements in foundation business."

Jan 1, 2014

By Kalyani Devabhaktuni, Mike Minton, Mark T. Howe, Yan Zhang

During the procurement phase of a Design-Build (DB) project, design-build contractors must often commit to a fixed price based on limited or incomplete geotechnical information. This lack of information can result in an inaccurate assessment and allocation of project risk to either the contracting authority or the DB contractor. This paper presents a case study of an elevated water tank supported by mixed ground improvement techniques, including Vibro-Compaction (VC), Aggregate Piers (AP) and Compaction Grouting (CG) in East St. Louis, Illinois. An adaptive design and contracting approach provided the best value solution for a complicated set of geotechnical problems, including static bearing capacity and settlement concerns as well as liquefaction induced settlement. Close cooperation between the owner, the tank contractor, the geotechnical engineer and the ground improvement contractor was essential to produce an effective solution. Ground Improvement techniques resolved the geotechnical challenges at the site through adaptive design methods, utilizing progressive rounds of verification and real time data acquisition to achieve performance objectives. This paper details the evaluation of geotechnical criteria, the selection of ground improvement techniques, the adaptive design and implementation of ground improvements, as well as contracting methodologies used to ensure that the best value was provided. PROJECT INFORMATION In November, 2016, CB&I Storage Tank Solutions (McDermott) submitted a design/build proposal for an elevated water tank for Illinois American Water Company (IAW) in East St. Louis, Illinois. The purpose of this tank was to have backup water capacity for power generation. In the RFP, IAW requested two alternate styles of tank: Option 1, a 1250 Million Gallon (MG) Composite Elevated Tank or Option 2, a 1250 MG Waterspheroid tank. Option 1 consisted of a steel tank supported on a concrete tower. Option 2 consisted of a steel tank supported on a steel shaft. The height (determined by IAW) was 140 feet to the top capacity line measured from top of floor slab.

Jan 1, 2019

By Madhav, V., M. R., Ahmad, Padmavathi, M. S.

Modulus of deformation (Es), also referred to as elastic modulus is dependent on many variables such as type of loading, degree of anisotropy and non-homogeneity of strata, etc. and is one of the most challenging soil parameters to estimate. Modulus of deformation of soil can be obtained from elemental tests in the laboratory, from in-situ tests or on the basis of correlations with other soil parameters. Back analysis of full-scale loading test is the most appropriate method for the estimation of the deformation modulus since the effects of installation and pile-soil interactions are accounted for. Moduli of deformation of the ground are estimated from different pile load tests, viz., compression, pull-out, and lateral load tests and compared. The method of interpretation of pile load test is based on the initial liner portion of the load-displacement curve. Theoretical solutions of Poulos and Davis (1980) and Madhav and Poorooshasb (1988) that relate settlement or displacement with load based linear elasticity theory are used. It has been established that the modulus of deformation of the ground is not unique but depends on the type of test and the type of loading. The differences can be significant.

Sep 1, 2022

By Kevin Green, Iván Contreras, Aaron Grosser, Jon Ausdemore, Rachel Leier, Amr Ragy

"Construction of a new tailings dam was required to increase tailings storage capacity at a trona mine near Green River, Wyoming. The new dam was founded on overburden soils underlain by both fractured and competent bedrock. The stored tailings and water had high salt content, resulting in salty seepage water. To reduce the impact of the salty water on groundwater and the Green River, the design of the new tailings dam included a 257,260 SF (23,900 m2) seepage cutoff extending into competent rock.An extensive subsurface characterization was performed prior to completing the design and suitable seepage cutoff methods were evaluated. The approach selected was a full replacement panel using hydromill and clamshell for construction and self-hardening slurry (SHS) for the wall material. Laboratory testing was performed and ongoing monitoring has continued to evaluate the hydraulic conductivity and seepage cutoff performance in the briny environment.The paper includes project background, the collaborative approach and outcomes of the QA/QC program, and the monitoring results for the seepage cutoff wall.PROJECT BACKGROUNDCiner Wyoming, LLC (formerly OCI Wyoming, LLC) owns and operates the Big Island Mine facility near Green River, Wyoming. This underground trona mine has produced soda ash since 1962. The Greater Green River Basin covers much of southwestern Wyoming and extends into northeastern Utah and northwestern Colorado. The Ciner facility is located in the Green River Basin, which is part of the Wyoming Basin physiographic province. The Green River runs to the west and the south of the Ciner facility.Beginning in the early 1990s, Ciner primarily disposed tailings underground in mined-out panels. However, in recent years, underground storage has become limited and some disposal has transitioned to the ground surface. Long-term planning revealed a need to expand Ciner’s surface tailings disposal capabilities. Pond 2, a previously permitted disposal area, was identified as the most viable location for a storage facility. The Pond 2 site is directly north of the Ciner plant facilities, northwest of the active Upper Delta tailings storage facility, and northeast of the Green River (Fig 1)."

Jan 1, 2016

By Roberto A. Lopez, Eric Lindquist, Jon Bussiere, Dean Iwasa

"The new 11-story U.S. Federal Courthouse building in downtown Los Angeles demanded a cost effective foundation system capable of attaining a strict total settlement criterion of 0.5 inches (12 mm) under high applied loads. A design-build ground improvement system consisting of 3 ft (0.9 m) and 7 ft (2.1 m) diameter deep soil mix (DSM) columns embedded into the relatively soft Fernando Formation bedrock was selected for the project. The DSM columns support applied stresses of up to 8,800 psf from four large concrete core elements that transfer concentrated building loads to a 3 to 6 ft (0.9 to 1.8 m) thick reinforced concrete mat. The soil mixing ground improvement solution provided flexibility by allowing installation of the DSM columns around existing belled caissons left in place from prior structures, and by allowing repositioning of some of the DSM columns to avoid other existing obstructions in the fill. DSM spoils were used to construct a 2 ft (0.6 m) thick load transfer platform on top of the DSM columns. Quality control measures included utilizing equipment outfitted with automated data acquisition systems, performing three full scale load tests, performing daily wet-mix sampling and compression testing, performing full-depth coring and unconfined compression testing on core samples, and using a borehole acoustic televiewer to evaluate the uniformity of the DSM columns where core recovery was problematic. The results of subsurface investigation and the load tests were used to develop 3-dimensional finite differences models for evaluating stress distribution and deformation of the foundation system.INTRODUCTIONThe new U.S. Federal Courthouse building is currently under construction in downtown Los Angeles, California. The new courthouse will be 11 stories tall with one partial below-grade B1 basement level. The building will have four structural core elements that extend from the main building foundation at the B1 level to the top of the structure. The majority of the building loads will be transferred through the structural core elements to a new 3 to 6 ft (0.9 to 1.8 m) thick reinforced concrete mat beneath the central portion of the structure. The foundation pressures beneath each of the core element locations will be approximately 6,200 to 8,800 psf (300 to 420 kPa) with lower foundation pressures at locations farther away from the central core area."

Jan 1, 2015

By Ganesh Deepak K., Anjana R. K., Dr. Kumar Pitchumani N., Rajasekharam R. M. V. M. S. S.

The Phase 2 of Chennai Metro is being introduced in the city to ease the dependence on the existing transportation systems. Phase 2 is a combination of underground and elevated metro stretches comprising of three corridors. The current study focusses on the underground stretch of Corridor 3 which has a total of 29 underground stations. Construction of the underground cut and cover stations results in ground movements, which in turn impact the structures adjacent to the excavations. The greenfield ground settlement can be evaluated with the help of empirical approach or an approach requiring finite element modelling (FEM). The paper compares empirical and FEM approaches with regards to ground conditions in Chennai. Further, with the predicted ground settlements, building damage assessment is performed. The damage category of a building is defined based on the estimated tensile strains. This paper also compares the building damage assessment with empirical method and finite element modelling.

Nov 1, 2022