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By Donald A. Bruce

"Abstract The Deep Mixing Methods (DMM), in their current forms, have been employed in the United States since 1986, although an earlier version had seen service from 1954. The earlier developments were strongly influenced by practices in the Nordic countries and Japan, while by the late 1980’s several DMM systems had been developed in the U.S. itself. Since then, DMM has continued its evolution, principally via the challenges of a series of large, landmark projects, but also via distinct, significant technological advances. This paper highlights the key points in the history of DMM in the U.S., and provides an overview of the different methods currently in use.In the BeginningIt is a common misconception that the history of applications of the Deep Mixing Methods (DMM) in the United States dates from 1986 when SMW Seiko Inc. — a subsidiary of Japan’s Seiko Kogyo Company — was established in the Bay Area. However, the author believes that Intrusion Prepakt Co.’s patented MIP (Mixed in Place) system had been used, albeit sporadically (about 30 projects are recorded), since 1954 (FHWA 2000, 2001). Ironically, by 1961 this single auger method had been extensively used under license in Japan for excavation support and groundwater control — by the Seiko Kogyo Company. By 1972, the original MIP technique had been succeeded by more advanced Japanese methods, involving multiple augers. Intrusion Prepakt have long since become defunct.The first systematic studies of contemporary Deep Mixing Methods in Japan began in 1967 when the Port and Harbor Research Institute of the Ministry of Transportation began laboratory testing using granular and powdered lime for treating soft marine soils. Fundamental studies continued through the early 1970’s, by which time the development of industrial scale equipment was well advanced, having its first application on a marine trial near Haneda Airport. Coincidentally, laboratory and field research also began in 1967 in Sweden (“Swedish Lime Column Method”) for treating soft clays using unslaked lime. Reportedly the progenitor was a Norwegian, Kjeld Paus, who had made observations on fluid lime columns in the U.S. It would seem that developments in Japan and the Nordic countries proceeded independently until 1975 when the technology leaders from each group (Broms and Boman; and Okumura and Terashi, respectively) presented their — very similar — findings at a conference in Bangalore, India. Limited technical exchanges ensued thereafter.Whereas the Nordic developments continued to focus on the use of dry reagents (cement and lime) and relatively light equipment compatible with operating on and in very soft clays and organics, the Japanese progressed into the use of fluid reagents (cement-based grouts) and heavier equipment for both marine and land-based projects. Thus, by 1986, there were a large number of proprietary (wet and dry) DMM systems in Japan, and a rapidly growing market already by then accounting for over 12,000,000 m3 of ground treatment."

Jan 1, 2014

By Michael Arnold, Bob Faulhaber, Joe Nichols

"Center Hill Dam is a critical part of the infrastructure controlling floods at the Caney Fork River and reducing flood levels at the Cumberland, lower Ohio and Mississippi Rivers. The Center Hill Dam Foundation Remediation Project was necessary to address Karst features in the foundation rocks and observed signs of distress of the dam. From 2011 to 2014 BAUER Foundation Corp. (BFC) performed deep foundation works for this project. The executed features of work include the installation of two walls. The first wall extends throughout the clay embankment into the underlying rock to provide encasement during the construction of the second wall. Its width of 7.4 feet makes it the widest diaphragm wall ever installed. The second wall is the actual seepage barrier and provides a continuous 2- feet wide wall. It extends through the first wall into the underlying rock and is up to 300 feet deep. The paper introduces the project, the requirements specified by United States Army Corps of Engineers (USACE) for encasement and barrier wall and the approaches taken by BFC. It discusses the ground conditions and describes the excavation equipment as well as the excavation methods used. A special focus is put on the steering capabilities of the hydrocutter equipment and the verticality performance.PROJECTBeginning in 2011, BFC was tasked by the USACE with the installation of a seepage barrier/cutoff wall at the Center Hill Dam Foundation Remediation project under a partially performance based specification. The remediation was necessary due to karst features in the foundation rocks and observed signs of distress, which led USACE to rate the dam with the most critical dam safety action classification (DSAC I). The executed features of work include the installation of two walls. The first wall, an encasement wall, extends vertically through the clay embankment and is embedded minimally into the underlying bedrock to provide embankment stability during the construction of the second wall, the barrier wall. The encasement wall is constructed of overlapping panels 7.4 feet (2.25 m) wide, which is the widest diaphragm wall ever installed, and up to 210 feet (64 m) deep. The second wall is the seepage barrier and provides a continuous 2 feet (0.6 m) wide wall consisting of overlapping panels. It extends through the encasement wall into the underlying bedrock and is up to 307 feet (93 m) deep. BAUER BC40 and BC50 hydrocutters mounted on MC96 and MC128 foundation cranes were used to perform the majority of the works (Figure 1). Excavations were performed under bentonite slurry (encasement wall) and water (barrier wall) and concrete was poured with the tremie method. Adding to the challenges, the project had to be executed in an environmentally sensitive area. Based on the high risk, a special focus was put on monitoring, quality control and geometric accuracy. The WallTracker information management system was used to share all relevant data between BFC and USACE (Roff et al. 2014)."

Jan 1, 2017

By Christian Besson

This article describes the implementation of a new jointing process for use between diaphragm wall panels. This process was initially introduced on the SOCATOP work site in uburban Paris (which involved the closing of the western section of the A86 bypass road), on a tunnel ventilation shaft. This brand new system upgrades the potential offered by other types of joints available and enables both ensuring the continuity of panels for structures over 40 m in depth under the strictest safety conditions and constructing shafts with diameters of less than 15 m. A patent for this process has recently been filed.

Jan 1, 2002

By James S. Graham

Foundation pile driving hammers used in New York City in the past 100 years have been drop, steam, compressed air, diesel, and hydraulic. In 1992, the first hydraulic hammer in the New York City area was purchased by Norwalk Marine Contractors, Inc. from Junttan in Finland. It was bought because of its variable energy and ease of mobilization, not because of its higher transferred energy. Heller and Johnsen engineers instrumented hydraulic hammers on nine jobs. The measured transferred energy for the nine jobs was found to average approximately 80 percent. There is no clear consensus regarding the reasons for the hydraulic hammer being more efficient in delivering energy to the pile as compared to single-acting steam/air impact hammers. To minimize pile damage during installation, and to minimize footage overruns, an up-to-date version of the wave equation software that includes an efficiency value of 0.95 for hydraulic hammers is now used.

Jan 1, 2000

There are many ways to classify structural slurry wall elements, but the DFI committee chooses to limit these descriptions to three functional requirements, namely: design function, plan configuration and type of panel reinforcement. (See Figure 1 in Part IV for panel classification). Slurry walls can function as: 1. Curvilinear or linear elements for temporary and/or permanent structures to resist lateral forces transferred from the ground, water, earthquakes and various surcharge loads. 2. Load bearing elements in various plan shapes to resist vertical forces. 3. Combination Elements to resist combined forces under conditions 1 and/or 2. For example, elliptical shafts with various openings for tunnels and conduits have been commonly used for deep excavations.

Jan 1, 2005

By Christian Hoyme, Jochen Maurer

Most of the current foundation projects are suffering from disconnected information silos. In the first silo there is the planning of the project with corresponding data, presented by paper or digital drawings. Here will Building Information Modeling (BIM) be one of the trends for the future. We will see more and more projects leaving the “old way” of 2D drawings and moving into 3D planning including metadata of the foundations. But even with a perfect BIM model of a jobsite, we are not at final end of digitalization. While execution of the project at the jobsite, a second data silo is evolving. Data collected directly from construction equipment and manual measurements is currently undervalued in most projects. Paper is passed to the equipment operator and major data from measurements on site are noted on paper and digitized afterwards. Automatically collected data is not be used to create site progress reports or similar report. So, the real “data” just flows around without connection to any other data already existing in projects. And then the third silo arises: The documentation of the project. Data collected on paper es reentered to create some basic documentation of the work handed over to the client. Spreadsheet software is still the “tool-to-be-used” to create at least some documentation. Finally, the documentation is not connected to the data created while planning and not connected to the automatically collected data from the jobsite. A connected jobsite in the foundation industry must link these information silos and have to create a full data-workflow from the design through the execution to the as-built documentation. INTRODUCTION Building information modelling (BIM) is currently the most popular term of construction business in Germany and probably all over the world. But as often there are many different definitions out there and everyone has his own definition or at least understanding what BIM is about. But for sure it is the most relevant for the construction industry in the near future. Most popular is the digital twin for the upper structure of a building. In most cases the BIM models just shows the building itself, but there is more to be implemented. For example: projects where a special foundation is needed, BIM should include also the foundation elements with meta data. There are several advantages. Not only the clash detection of anchors, but also the possibilities to check the interaction with neighbor constructions, power lines and so on are a use case. For sure most of the special foundation elements are not relevant for the whole lifecycle of a building. But during construction and later the demolition the information about the hidden elements is important and gives a benefit to all stakeholders. In the future there will be not the question: “What is already in the ground?”. The risk for following construction projects on the same ground will be minimized.

Jan 1, 2019

By Rozbeh Moghaddam, William D. Lawson, Priyantha W. Jayawickrama, Hoyoung Seo, James G. Surles

"This study provides calibration of resistance factors (?) for design of driven piles to implement Load and Resistance Factor Design (LRFD) for bridge foundations using Texas Cone Penetration (TCP) Test data. The basic research approach was to compile a database of published full-scale load tests including projects from the Texas Department of Transportation’s (TxDOT) historical archive and projects from neighboring state DOTs. Load test results from neighboring states were leveraged by performing new geotechnical borings with TCP tests at the project sites. The final dataset consisted of 30 load tests performed on precast square concrete piles, with pile widths ranging from 356 to 508 mm and penetration depths ranging from 5.2 to 25.5 m, driven in soils. Ultimate capacities for each load test were interpreted based on Davisson, 5%, and 10% settlement criteria. These measured ultimate capacities were compared against predicted capacities estimated from TCP blow count values (NTCP) and design charts following the procedures outlined in TxDOT’s Geotechnical Manual. From the comparisons, statistical parameters of the biases (??= measured capacity/predicted capacity) such as mean and coefficient of variation were obtained. Resistance factors (?) for LRFD were then determined using Monte-Carlo simulations for each ultimate capacity criteria with the target reliability indices of 2.33 and 3.00.INTRODUCTIONThe Texas Department of Transportation (TxDOT) has used the Texas Cone Penetration (TCP) test since its development in the 1940s. The TCP test is an in-situ penetration test to characterize the materials encountered during geotechnical exploration. Texas currently maintains over 53,000 bridges in the National Bridge Inventory (FHWA 2016), and most of these bridges plus other transportation infrastructure in Texas are supported by foundations designed using the TCP test and its associated foundation design method. The Oklahoma DOT adopted the TCP test and foundation design approach in the 1970s, so the foundations for most of the 23,000 bridges in Oklahoma’s inventory were also designed using the TCP method. With this significant body of experience, the TCP method has been viewed as a straightforward, relatively easy-touse foundation design method that consistently yields safe, serviceable, economical, and maintainable foundations. TxDOT’s deep foundation design method is documented in the TxDOT Geotechnical Manual (TxDOT 2012) and currently employs the allowable stress design (ASD) approach. However, the Federal Highway Administration (FHWA) has mandated that the states begin to implement the LRFD method in place of the older ASD approach (Densmore 2000). This paper presents resistance factors at ultimate limit state (ULS) for design of driven piles using the TCP test, resulting from efforts to be in compliance with the FHWA policy."

Jan 1, 2017

By Jeffrey A. Schaefer

The Olmsted Locks and Dam project is located on the Ohio River approximately 16.5 miles upstream of its confluence with the Mississippi River. It consists of twin 1200 ft. locks with floating and fixed approach walls, five 110 ft. wide tainter gate bays, a 1400 ft. wide navigable pass boat operated wicket gate section, and a 400-ft. section of fixed weir (Fig. 1). The project will have a total cost over 1.0 billion dollars, and as such is one of the largest civil works project underway in the Corps of Engineers.

Jan 1, 2001

By A. E. Fiorato

A test program was conducted to evaluate use of high-strength concrete in drilled shafts (caissons). The objective of the program was to determine if internal temperatures developed during cement hydration, or other characteristics of high-strength mixes, affect in-situ strength and stiffness. This paper covers strength results. Two 10-ft (3.0-m) diameter by 40-ft (12.2-m) deep caissons were constructed using two different commercially available high-strength concretes, a "low-heat" and a "high-strength" mix. Measured 6x12-in. (150x300mm) moist cured cylinder strengths at 56 days were 13,690 psi (94 MPa) for the "low-heat" mix and 17,130 psi (118 MPa) for the "high-strength" mix. Compressive strengths and moduli of elasticity of cores taken from the caissons were compared to those of companion cylinders made during casting of the caissons and stored in a moist room. Strengths of 4x8-in. (100x200 mm) cores taken at four ages and tested between 34 and 398 days averaged 81% of strengths of 6x12-in. (150x300 mm) moist cured cylinders at corresponding ages. In-situ (core) strengths of the caissons did not appear to be measurably affected by temperature. However, the data indicate that core strengths were sensitive to level of consolidation, as reflected in entrapped air voids. Overall, the results indicate that high-strength concretes can be used in drilled shaft (caisson) foundations.

Jan 1, 1991

By Eric S. White, Thomas J. Sabourin, Khuram R. Mohib

"This paper presents the challenges associated with the design and construction of a steel sheet pile cofferdam supported with one level of grouted anchors in clean to silty sand with gravel. The initial assessment of the subsurface conditions indicated loose to medium dense soil with intermittent dense to very dense layers with no occurrence of cobbles and boulders. Sheet piles were proposed to be installed to a depth of 24 m below the ground surface to limit dewatering requirements for the cofferdam. During sheet pile installation, refusal of piles occurred at multiple locations forming passages for increased flow into the cofferdam. Modifications were made in the design of the dewatering system as a result of the increased flow. Finite element modeling was used to select the necessary modifications to the dewatering system within the cofferdam. Wells were installed based on the findings of the numerical model. Model simulations showed good comparison with monitoring of the field installed dewatering system.INTRODUCTIONIt is necessary to consider the impact of the ground water, subsurface stratigraphy, strength, and drainage behavior of the soil for the design and construction of cofferdams. This paper presents a case history of the construction of a cofferdam in Northern Ontario, Canada. The project consists of the construction of a powerhouse, intake, and tailrace which will generate around 28 MW of renewable clean energy by diverting water from New Post Creek through a power house and discharge into the Abitibi River. The focus of this paper is the dewatering and excavation support required to permit construction of the powerhouse. The layout of the cofferdam is shown in Fig. 1. The cofferdam for the powerhouse is rectangular in shape with sheet piles on all four sides intended to be driven to the design toe El. 101 m. The east and west walls have a length of 46.3 m. North and south sides are 47.6 m long; and in addition, two cantilever sheet pile walls bound the tailrace on the west side and two cantilever walls were installed on the east for construction of the penstock inlet. The ground surface in the powerhouse cofferdam area, before commencement of sheet pile driving, was brought to El. 125; the ground then slopes up to the East, toward New Post Creek, and the site is bounded on the West by the Abitibi River. 186 pairs of sheet piles were used to create the cofferdam and cantilever walls. The deepest excavation is to elevation 114.4 m. Within the west half of the cofferdam footprint, the base of excavation slopes upward at 3H: 1V to facilitate the tailrace discharge into Abitibi River.SOIL STRATIGRAPHYThe cofferdam design was based on the geotechnical investigation conducted by AECOM (2014) which included two relevant boreholes near the powerhouse footprint. The ground elevation at the time of investigation varied between 131 to 129 m. The material observed to the full depth of investigation was comprised generally of coarse to fine sand and gravelly sand or a sand matrix with gravelly inclusions. Some intermittent layers of clay and silt intrusions were also observed. Generally the soils grade finer away from the river. SPT N60 values were recorded in two borings during the field investigation with values reported from 3 to 92. The in-situ conditions ranged from compact to dense with some loose and some very dense zones. Figure 2 shows the variation in SPT N60 values with elevation."

Jan 1, 2017

By Nicolas Denies, Gust Van Lysebetten, Bart Lameire, Jan Maertens, André Vervoort, Noël Huybrechts, Flor De Cock

"Abstract Originally developed for ground improvement works, the deep mixing method (DMM) has increasingly been applied in recent years for the realization of soil and water retaining structures and as alternative to traditional foundation solutions. From practice, there is a real need for practical guidelines dealing with the execution, the design and the control of such applications. With the aim of developing such guidelines, the BBRI ‘Soil Mix’ project was initiated in 2009. Within this research project, deep soil mix (DSM) material from 38 Belgian construction sites has been tested. In spite of the large advances in the mechanical characterization of the DSM material, one major issue remains the representativeness of the typical core samples in comparison with the real scale behavior of the soil mix elements. There is among others the question of the influence of the unmixed soft soil inclusions on this behavior and the issue of the scale effect which must be considered in the design. In order to investigate these questions, 8 large scale UCS tests and 17 large scale bending tests have been performed on excavated soil mix elements. The present paper discusses results of this experimental campaign, presents some research perspectives and highlights different aspects related to the design of soil mix elements for the realization of retaining wall or foundation solution.INTRODUCTIONSince several decennia, the deep mixing method (DMM) has been used to improve the strength and deformation characteristics of weak soils. In recent years, deep mixing has increasingly been applied – in Belgium and in other countries – for the realization of soil and water retaining structures and alternative foundation concepts. With regard to the execution of the DMM, one can refer to the European standard EN 14679 on deep mixing (2005) that was elaborated under the umbrella of CEN TC 288 “Execution of special geotechnical works”. However, from practice, it has been experienced that this execution standard does not provide enough pragmatic information and guidelines, in particular for the more recent applications of the deep mixing method (with retaining and bearing functions). The same need by the sector for guidance rules linked to design aspects in the context of Eurocode 7 was experienced as well. With the aim of developing such guidelines and in order to provide feedback to the European standardization platforms, the Belgian Building Research Institute (BBRI) has initiated the BBRI ‘Soil Mix’ project (2009-2013) in collaboration with the KU Leuven and the Belgian Association of Foundation Contractors (ABEF), the Belgian branch of the EFFC. Within this research project, deep soil mix (DSM) material from 38 Belgian construction sites, with various soil conditions and for different execution processes (CVR C-mix®, TSM and CSM), has been tested (Denies et al., 2012)."

Jan 1, 2014

By Takefumi Takuma, Ali Fayad, Shigeru Kambe

"This paper discusses the unique design and construction circumstances of the cantilevered dual sheet pile walls and the Accordion Sheet Pile Wall for the repair and upgrade of the East Garden Grove-Wintersburg Channel in Huntington Beach, California that was concluded in 2014. It also describes the 2008 Emergency Sheet Pile Project for the same channel. Both projects utilized the Press-in Piling Method for its low noise and almost no vibration advantages.BackgroundThe East Garden Grove-Wintersburg Channel is part of the Orange County Flood Control District (OCFCD) and is operated and maintained by OC (Orange County) Public Works (see Figure 1 for its location). The channel, referred to as OCFCD facility # C05 (C05), had suffered significant toe undercutting and slope erosion of its levee due to a series of storms. These began after the facility was constructed in the 1960’s and culminated in 2005. Consequently, the levee was deemed significantly deficient and was eventually declared as a local emergency in 2007. C05 was an incised channel and its levee was constructed primarily from native materials. Operation and Maintenance (O&M) personnel notified the design staff at OC Public Works to be aware of major consequences associated with the dilapidation problem in the most downstream reach of the channel in the vicinity of the Bolsa Chica Wetlands Restoration Project. In 2007, the Orange County Board of Supervisors declared a local emergency to fix the levees with sheet piles to be driven by the Press-in Piling Method, hydraulic pushing piles into ground by holding onto previously installed piles. The project that ensued represented the first in-tandem use on the West Coast of the United States of the Press-in pile driver with its GRB System (Press-in pile driver, a support crane and pile transporter travel on top of already-driven sheet piles). This is further discussed in this paper in the sections titled “Press-in Piling Method” and “GRB System”, respectively. The project repaired approximately 3,800 feet of erosion on the north levee of C05 with 45-foot long cantilevered sheet piles. The sheet piles design constraints are discussed in this paper in the section titled “C05 2008 Emergency Sheet Pile Project (Phase 1)”. Between 2012 and 2014, another mile’s worth of levee reach was improved with the Soil-Mix-Sandwich (SMS) Method. This concept consisted of deep soil cement mix (DSCM) columns sandwiched within the dual rows of sheet piles. Additional details on the SMS, its DSCM construction, and its hybrid geo-structure design concepts are well beyond the scope of this discussion, which is primarily focused on sheet piles. Instead, the interested reader is referred to two papers on the SMS and its DSCM metrics (Fayad, 2015; and Arora, et al., 2015). These were presented and published in the Proceedings of the Deep Foundations Institute (DFI) 2015 Conference on Deep Mixing. Hence, in the section of this paper titled “C05 SMS Dual Sheet Piles Project (Phase 2)” only the sheet pile design constraints of the SMS are covered. Finally, in the area where the project traversed the Alquist-Priolo zone of the Newport-Inglewood tectonic fault, an expandable and deflectable sheet pile wall was used to isolate the flood channel from the Bolsa Chica wetlands. Its details are addressed in the section titled “C05 Accordion Sheet Pile Wall (Phase 2)” of this paper."

Jan 1, 2017

By Mu Chen, Ye-Shuang Xu, Dong-Wei Hou, Shui-Long Shen, Huai-Na Wu

"This paper presents a laboratory investigation on the mechanical behaviors of the cement-clay admixture improved by polypropylene fiber. Cement can significantly improve the clay admixture. The fiber additive also improves the strength and ductility of the improved clay. The Unconfined Compression Strength (UCS) of the polypropylene fiber-reinforced cement-clay presents an overall trend to grow with the increase of fiber length. The improved clay reached its peak strength at the fiber content of 0.5%. Then the UCS of the improved clay will slowly reverse if the fiber content continues to rise. For study of curing time, improved clay behaves better in its early strength, but an inhibition will be brought about if fibers are excessive.INTRODUCTIONGround improvement technology is essential for construction of structures in soft ground. Some traditional techniques often cost much but result in little. For instance, along the coastal region of China, soft ground is often improved by backfill with high quality sandy soil transported far away, leading to high additional haulage costs and long construction period. Reutilizing the excavated soil as backfill or subgrade after treatment, by contrast, will be more economical and effective (Hufenus et al., 2006). Many researches have been conducted to improve the compression strength of soft soil, among which, the method of mixing the soft soil with cement and fly ash is one of the most common ways (Kolias et al., 2005; Horpibulsuk et al., 2009; Porcino et al., 2012). It is known that soil resists well against compression and shear force but behaves poorly in resistance to tension. Therefore, utilizing tensile elements such as fibers and strips to improve the tensile strength will be effective because of its strength isotropy, better durability and cost effective (Haeri et al., 2000; Kaniraj and Havanagi, 2001; Consoli et al., 2010)."

Jan 1, 2015

By B. Sivarama Sarma, Biswabikash Rout

"Seepage control has to be achieved with plastic concrete cut-off diaphragm walls in dam structures. Materials selected for construction of cut-off walls must be durable, impermeable and have stiffness comparable to the surrounding soil.Plastic concrete provides a feasible and economical solution for construction of durable and impermeable cut off walls for dam structures. Plastic concrete wall should not be understood as a concrete wall with similar mechanical properties of concrete used in buildings, piles and spillways sections. Though it consists of the same materials as those of conventional concrete it has the major differences in end product due to predominant addition of bentonite slurry in the mix with very high water cement ratio. This makes the hardened concrete with very low compressive strength less than 5MPa and high failure deformations after the peak load.This technical paper examines a case study, the typical specifications on demand for construction and the issues corresponding to misunderstanding of the material as a structural grade concrete material. Conclusions were drawn based on a few project site quality data and trial mix experimental data. The anomalies in specifications on demand for construction of curtain wall in a dam structure were removed with modifications.INTRODUCTIONDiaphragm walls which are constructed in trenches made of plastic concrete basically serve the function of seepage control under confined measures. They should have the ability to sustain and undergo large plastic strains as compared to conventional concrete. The three basic mechanical properties of plastic concrete cut-off walls are to have least permeability, minimum strength to retain its shape and ability to undergo large deformations under confined loading conditions. The constituents of plastic concrete are cement, bentonite, coarse and fine aggregates, chemical additives to improve flow of concrete and sometimes to retard the setting time and water."

Jan 1, 2017

By Paul M. Wiltcher

This paper discusses how benefits in engineering design can be achieved from combining existing GRP concrete design guidelines with carbon steel design codes primarily made possible due to the increase in the constitutive properties of modern composite rebar or GRP. It also examines the technical and practical considerations necessary to both construct and ensure the integrity of composite rebar during transportation and handling on site and the measures taken by Franki-Cementation Joint Venture to ensure the safe deployment of the GRP in the workplace on the Noord/Zuidlijn Project in Amsterdam between 2003 and 2006.

Jan 1, 2006

By François G. Bernardeau

Cement-bentonite (C-B) slurry walls have been used for ground water cutoff in deep excavations, contamination containment, and other applications. Hydraulic conductivity is of great concern for cement-bentonite slurry walls. The quality control program usually specifies permeability and strength tests to be performed in a laboratory on samples cast in the field and cured for a certain time. Currently there is no widely accepted in-situ test method for the performance of the constructed slurry wall. A recently constructed cement-bentonite slurry wall in South Carolina included a 200-foot-long test section done in advance of the production of an 8,300 foot-long wall. Intensive tests and investigation were conducted during and after the test section construction: Monitoring piezometers were installed using wet insertion method and packer tests were conducted in boreholes drilled in the post-28-day-cure slurry wall. The permeability measured from the packer tests was about two orders of magnitude higher than the design and the laboratory test values. Additional investigation was performed using a video camera to inspect the borehole walls especially the packer test sections. Test pits were excavated to observe both sides of the cement-bentonite slurry wall. A thorough inspection was conducted to evaluate the integrity of the wall. The lessons learned and issues regarding the disturbance effects of in-situ testing of cement bentonite slurry walls is presented and discussed.

Jan 1, 2008

By Kazimierz Gwizdala

In recent years, in Poland the ATLAS piles have been successfully applied for some constructions near Gdansk. The piles have been used as foundations for housing and another areas of civil engineering, in delta Vistula geotechnical region, characterized by weak, highly compressible soils represented by mud and peat, lying in sub-surface layers, several meters thick. Usually below are dense sandy soils or gravel. In all cases, the base of ATLAS piles rested on sandy soils. The analysis of pile bearing capacity has been discussed and verified by static pile load tests (SPLT). The load-settlements characteristics obtained were satisfactory. In the paper, the results of geotechnical investigations as well as calculations and load tests are shown. The ecological aspects of ATLAS piles application within highly urban areas of the cities and complex geotechnical conditions are emphasized.

Jan 1, 2006

By X. L. Huang

This paper deals with the experimental and theoretic study of the contact pressure beneath the deep foundation of Beijing International Hotel, The experiments have been carried out in project and in model footing 6.6m2. The result of measurements shows the contact pressure at the edge is greater than that at the center. The theoretic analysis on the base of elastic theorey is in good agreement with the test if the proposed assumption used.

Jan 1, 2010

By B. Ladanyi

The design philosophies for piles in unfrozen and frozen soils are compared, and their similarities and differences are underlined. It is shown that in frozen soils, the long term behavior of a pile is difficult to predict, because of inadequate knowledge on the behavior of adfreeze bond with time, and on the value and variation of the lateral normal stress acting on the pile. Both of these problems are discussed in the paper on the basis of laboratory tests and theoretical analyses.

Jan 1, 2010

By William M. Camp

An extensive design phase testing program in which 10 piles and 2 drilled shafts were instrumented and statically load tested to failure, was undertaken to establish relevant foundation design parameters for two bridges in Charleston, South Carolina, USA. The bearing strata at both test sites was a calcareous, overconsolidated, firm to very stiff, slightly sandy, clayey silt (locally known as Cooper Marl). Confirmation dynamic and static loading tests on production piles indicated only 50 to 60% of anticipated pile capacities; including consideration of time effects. Supplemental subsurface explorations did not reveal any significant variations in marl properties. Ultimately, 22 static and 75 dynamic tests were performed on production piles for a 2 mile section of the project. Pore water pressures in the marl were also monitored during and after pile driving. A study of unit skin friction in the marl as a function of time revealed two distinct trends: piles driven in areas with a sand overlaying the marl gained more capacity significantly faster than those driven through a clay or silt. Although the insitu marl properties are apparently similar across the site, the material immediately above the marl evidently has a large effect on pile capacity. This effect of overburden on pile capacity was verified by testing piles over a period of two years.

Jan 1, 1993