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By Debra F. Laefer

Jet grouting is a ground improvement technique that has become widely adopted over the past three decades, yet relatively little data has been published about performance characteristics of mixes under adverse conditions, such as the inclusion of clay lenses. This paper presents an experimental investigation on the impact of clay on the strength of jet grouting. A total of 150 grout samples were subjected to 0-10% levels of Kaolinite and Bentonite inclusion. While the Bentonite was introduced as a pre-hydrated slurry, the Kaolinite was mixed in two ways: in a pulverized condition and as large chunks. Sample strength and stiffness were measured at multiple dates within the first 28 days. With 10% clay inclusion all samples exhibited significant strength and stiffness losses. With some, substantial losses began with as little as 4% clay. Even a 1% clay inclusion tended to decrease strength and stiffness between one-quarter and one-third of the control sample. Depending upon clay type and inclusion method, results differed significantly with respect to strength and stiffness development and failure mechanism. Petrographic analysis is used to provide further insights as to apparently divergent behaviors.

Jan 1, 2009

By Marius B. Wechsler

A mathematical analysis is developed for the determination of the cases when HP-piles might be replaced by precast concrete piles. The analysis focuses especially on the "integral abutment-bridges" which are used on large scale in the Great Plains of the United States of America, The theoretical considerations are illustrated by a numerical example.

Jan 1, 1992

By I. H. Wong

The large diameter caisson foundations and their construction methods for three 50 to 60 storey high buildings in Singapore are described. The caissons are 5 m to 8 m in diameter and 40 m to 100 m deep, excavated either by hand or mechanised excavators or by drilling and blasting. Performance of the 50 storey DBS Building is described.

Jan 1, 2010

By Clyde N. Baker

The paper describes procedures used to predict the settlement performance of drilled shafts constructed under slurry through water bearing deposits to a dense bearing strata, considering both side resistance and end bearing. A full scale instrumented drilled shaft load test on a Jersey City, New Jersey highrise project is used as a case history to compare with prediction.

Jan 1, 1991

By Z. Y. Ding

This paper emphasize two points in piled wharf design which are important than structure calculation. First, during design of piled wharf on soft stratum, the bank slope stability is the first important item. Second, the live load, the backfill and the original ground's settlement will influence the wharf structure causes cracks. Two practical examples were illustrated.

Jan 1, 1991

By Takeru Fukaya, Tsutomu Namikawa

"The bending tensile stress occurs in the ground improvements when external forces are applied to the column and wall shaped ground improvements. Therefore, in the design of the column and wall shaped ground improvements, the tensile properties of the cement-treated soils become a predominant factor when the external forces induce bending moments. Then the tensile properties are required to design the ground improvements rationally.Three points bending tests are conducted to investigate the bending tensile properties of cement-treated soils in this study. Cement-treated soils mixed in a laboratory are used in the bending tests. The test specimens are prepared with the several mixing properties to study the relationship between the tensile properties and unconfined compressive strength qu. Bending tensile strength Tfb and fracture energy Gf of the cement-treated soils are evaluated from the load-deflection curves obtained from the bending tests. The experimental results indicate that Tfb and Gf are approximately proportional to qu.INTRODUCTIONThe ground improvement by deep mixing has been widely used for structure foundations, retaining walls and liquefaction mitigations. Recently column and wall shaped ground improvements by deep mixing method have been applied for economical reason. When external forces are applied to the column and wall shaped ground improvements, the bending tensile stress occurs in the ground improvements. Therefore, in the design of the column and wall shaped ground improvements, the tensile properties of the cement-treated soils become a predominant factor when the external forces induce bending moments. Then the tensile properties are required to design the ground improvements appropriately.Namikawa et al. (2007) conducted the finite element analysis to investigate the dynamic behavior of the lattice-shaped improved ground for liquefaction mitigation. In the analysis, an improved ground consisting of several grids in a line was chosen to study the basic behavior of the lattice-shaped improved ground. Fig. 1 shows a example of calculated tensile failure zones in the improved soil during the earthquake. Half of one section of the improved soil consisting of two grids in a line for the 8 m × 8 m grid was modeled in the case. In Fig. 1, the failure occurs at the bottom and upper corners of the improved soil grid. The analysis result indicates that the constitutive model which can appropriately evaluate tensile failure behavior of cement-treated soils is required to evaluate the performance of the lattice-shaped improved ground for liquefaction mitigation. In the analysis, the elasto-plastic model developed by Namikawa and Mihira (2007) was adopted for the cement-treated soil behavior. The elasto-plastic model can suitably describe the tensile failure behavior of cement-treated soils. In the elasto-plastic model, tensile fracture energy is adopted to determine a tensile softening relationship because it is difficult to directly measure the stress-strain relationship after the peak stress state in direct tension tests. However there is little experimental study on the tensile fracture energy of cement-treated soils."

Jan 1, 2015

By Emad W. Shublaq

Contractual site plans are implemented for executing pile foundations (5 x 5) at segmental concrete bridge. Project schedule demands have forced the contractor to find out the most economical procedure in achieving the goal. This paper presents a site management technique which is applied by the Contractor. This was found to be fruitful and as much as 60% saving was gained.

Jan 1, 1992

By [D. N. ] Naresh

During different activities pile installation like pile boring, concreting etc., it is likely that various problems, depending up on site condition may be encountered. There are possibilities that some of the activities if not correctly followed may affect the pile capacity. This paper describes few problems encountered during pile execution at different sites and presents the remedial measures undertaken to overcome them.

Jan 1, 1996

By Steve Thoman

After the 1989 Loma Prieta Earthquake, the California Department of Transportation (Caltrans) initiated an overview of the Caltrans Bridge Design Specifications (BDS) and bridge seismic design practice in California. This overview is continuing under the direction of the Applied Technologies Council (ATC-32), to review and revise as necessary existing standards, performance criteria, specifications, and practices for design and construction of new bridge structures within California. The ATC-32 project began in August 1991 and is expected to be completed in 1995. Since 1990, Caltrans project-specific seismic criteria have been developed and implemented on the I-280 and I-480 projects in San Francisco. Caltrans and an independent seismic safety review panel continue to develop and implement these criteria on other projects. In 1991 and 1992, project-specific seismic criteria were used on the I-880 reconstruction project in Oakland. The seismic safety review panel considered the I-880 seismic design criteria a state-of-the-art methodology to ensure seismic safety against collapse of bridge structures subjected to a maximum credible seismic event. This paper highlights the 1992 "I-880 Reconstruction Project Seismic Design Criteria Review" report prepared by the Seismic Safety Review Panel and Caltrans Division of Structures and will compare pre-1989 BDS and AASHTO methodologies to the I-880 criteria.

Jan 1, 1996

By Vahid Tajdar

The behavior similarity between pile and cone penetration test, has guided the researchers to use the CPT results in prediction of piles bearing capacity. In this article, artificial neural networks have been used to study about relation between cone tip and sleeve friction strength obtained from cone penetration test and ultimate pile bearing capacity, obtained from static pile load test. Artificial neural networks "ANNS" is a form of artificial intelligence. ANN tries to dramatize the human nerves & brain system biology structure in self-structure. In this article, the results of relevant studies about the prediction of ultimate pile bearing capacity in especial area of soils are presented by use of back - propagation neural networks. The results of static pile load test up to failure on 63 piles with closed end and CPT test results in the place of construction these piles use in order to confirm and creation ANN model. Comparing predicted ultimate pile bearing capacity by utilizing ANN with the numbers which are predicted by 5 common traditional methods shows that using of artificial neural networks is a suitable method for predicted ultimate pile bearing capacity in identified area of texture of soil moreover it has a better operation in comparison with common traditional methods.

Jan 1, 2006

By Michael T. Lambert

The purpose of the this paper is to demonstrate the benefits of using additional instrumentation during load tests of auger-cast-in-place piles. Traditionally, only load and butt displacement are determined during load tests. The results from and methods used to instrument 15 auger-cast-in-place (ACEP) piles as part of six projects are included herein. By instrumenting the piles, the distribution of load along the pile length and load transfer can be determined, allowing the pile capacity to be adjusted or the length/diameter of the pile to be adjusted for the a given required load. The majority of the piles tested were designed as end bearing piles on either shale or limestone bedrock. No discussion of Geotechnical Instrumentation can be started without acknowledgement of the "Red Book." The actual title of the book is Geotechnical Instrumentation for Monitoring Field Performance, by Mr. John Dunnicliff, John Wiley and Sons, 1993. Anyone undertaking an instrumentation program should thoroughly review the Red Book, paying particular attention to Chapters 3 and 4. Instrumentation should not be done just because it can be done. There must be an unanswered question or questions that can be answered with measured data before instrumentation should be considered.

Jan 1, 2000

By J. Matos e Silva

"Abstract The paper refers five examples of executed diaphragm walls with one to five levels of anchorages. For each example a comparison is made between the results of the design using the traditional criteria and the ones obtained by using the Eurocode 7 and the Portuguese Norm related to the EC7 (NP EN 1997-1 2010), as the Eurocodes consider the possibility of each European country to adopt their own geotechnical parameters as these may vary from one country to another. A comparison is also made with the behaviour of these diaphragm walls during its construction phase; so the values from the design that were adopted in the construction are listed in tables 2 to 6 in the “Construction Options” columns. From the referred examples the author presents his conclusions.1 - INTRODUCTIONIn the so-called “traditional criteria” the soil parameters (dry unit weight, angle of internal friction and cohesion) have values obtained through tests or empirically. It is assumed that the characteristic values of the soil parameters adopted in Eurocode 7 are equal to the soil parameters adopted in the calculations by the “traditional criteria”. In the present paper the design according to the EC7 was made considering only the ultimate limit states and the respective Cases A1 and A2.The partial coefficients used for the actions in the present paper were those on Table 1:2 - CONSIDERED EXAMPLESThe five examples correspond to the situations of figures 1 to 5, and the respective results are summarized in tables 2 to 6.For all the considered examples, that are case histories, a simplified method published by Matos e Silva (March 2000) was adopted. This method attains good performances when compared with other more sophisticated ones as the finite elements and the elasto-plastic methods as described in a paper published by Matos e Silva (2000). All the obtained values were compared between them and with the so-called “Construction Options” that were the values adopted by the designers of the considered examples. For the wall bottom length calculation two possible situations were envisaged:"

Jan 1, 2014

By KeerthiRaaj Subrmanian, Muthukkumaran Kasinathan

"A railway embankment is under construction between Nagapattinam to Thiruthuraipoondi covering 36.5 km. The sub-soil strata comprises of soft clay extending up to 10 m below existing ground level, which is subjected to stability and settlement problems. A trial stretch covering about 5 kilometer was improved using Prefabricated Vertical Drains (PVD) with surcharge was recommended to accelerate the consolidation settlement. The geotechnical characteristics of the subsoil are examined through laboratory tests on representative soil samples. Recent improvement in the finite element analysis has facilitated modeling of PVD in finite element software for computing the settlement magnitude and time rate of consolidation. In this study the theoretically predicted settlement magnitude and time rate of consolidation from Terzaghi.s vertical consolidation, Barron's radial consolidation are compared with the analyzed FEM results for both the cases with and without PVD improved embankment. The comparative analysis between FEM and predicted data hold good for stresses and the associated deformations. The excess pore water pressure was significantly lower and their dissipation was faster in case of embankment with vertical drains. Thus PLAXIS 2D tool shows fairly convincing results in comparison to the theoretical solutions.1. INTRODUCTIONFrom the earlier times civilization has been developed in a fashion either at the banks of river or near to the shore region, because of the easier availability of food and water. This over centuries made them as huge cities, consequently population rise made the increased necessity of highway, railways, port and even more ground for construction. As a stake researchers are pushed to make a low bearing ground into a massive carrier of skyscrapers, embankment, bridges etc. These low bearing ground suffers from total and differential settlement, slope instability. Hence, numerous ground improvement techniques were followed to eradicate these concerns which include preloading, piling, stone column, vertical drains and geosynthetic reinforcement. Among them Prefabricated vertical drain (PVD) are often used to accelerate consolidation of soft subsoil and has been the main soil improvement method used in improving the soft marine clay deposit (Chu et al.(2004); Chai (2001) and Arulrajah et al.(2003)). Literature review of embankment over soft clay deposit reveals that combination of PVD with preloading is widely considered as an economical and less time consuming ground improvement technique."

Jan 1, 2015

By Arash Khosravifar

The seismic design of extended pile shafts for the combined effects of dynamic shaking and liquefaction-induced lateral spreading is investigated using nonlinear dynamic finite element analyses (NDA). Results of NDA parameter studies are used to illustrate how inertia and lateral spreading loads combine during shaking. The NDA results are used to evaluate equivalent static analysis (ESA) methods. Implications for design practice are discussed.

Jan 1, 2010

By D. P. Nicholson

The current phase of office development at Canary Wharf in the London Docklands includes twelve multi-storey buildings varying from eighteen to forty stories in height. The area of Canary Wharf South comprises five multi-storey buildings with low level in fill podium and garden areas. Three of these multi-storey buildings have "pile-cap" designs where the entire building load is applied to the piles. The remaining two buildings have "piled-raft" designs where allowance is made in the design for part of the building load to be transferred to the raft formation. Using a piled-raft design approach has enabled savings to be made on the number of piles used below the raft. This paper describes the calibration analysis undertaken to validate the design method. The ground conditions at the Canary Wharf site are typically fill and recent gravel deposits over the overconsolidated clay and sand of the Lambeth Group. Below these strata is the Thanet Sand. The Lambeth Group provided the founding layer for the raft and contributed to the pile shaft resistance. The Thanet Sand stratum provided the bearing layer for the 1.5m diameter base grouted bored piles. The piled-raft design required an assessment of the building load transfer through the raft to the formation layer. This load transfer led to significant increases in effective stress in the soil below the raft and thence a corresponding increased the capacity of the piles. This interaction of the raft with the prepared formation contributed to between 27% and 45% increase in total vertical load carrying capacity of the piled-raft substructure compared with the pile-cap design method. The development of the piled-raft design was carried out in three main phases: ? Development of the approach and validation analyses. ? Design work on various schemes resulting in detailed design packages. ? Validation analyses using full 3D finite element analysis (presented herein). The validation of the piled-raft design approach was initially carried out against published case histories for piled-raft interaction. To improve on the validation work a full 3D finite element analysis of a simplified pile raft and superstructure (which contributes stiffness to the raft) was undertaken; the analysis included only a quarter of the structure due to assumed symmetry of the structure and vertical loading. This 3D validation analysis is presented herein. The analysis was carried out using the Oasys LS-DYNA finite element program. Prior to carrying out the analysis of the piled-raft an initial finite element analysis was carried out to back analyse a fully instrumented field pile test providing accurate modelling of a single pile performance. This back analysis allowed confidence in the soil parameters used in the 3D model; comparisons of shaft and base resistances between the pile test and the FE model calculations for the single pile are presented. The parameters provided in this work were then carried into the full 3D model of the piled-raft. The 3D model of the piled-raft structure included 18 piles (12 full piles and 6 half piles on an axis of symmetry of the model).

Jan 1, 2002

By Z. M. Zhang

Fracture grouting is a particular technique which can be used in soils and rocks with low permeability to increase groutability and penetration rates and to solve some special foundation problems by inducing limited and controlled zones of hydrofracture surrounding the injection source. The present paper describes the basic principles of hydrofracture and its application to grouting in deep foundations, and indicates some recognitions about the mechanisms and effects of fracture grouting.

Jan 1, 2010

By J. J. Beresford

The primary function of a support slurry is to provide stability during excavation. Today foundation structures can be designed around the additional friction afforded by the absence of the filter cake attributable to the use of polymeric fluids as support slurries. These fluids use pseudoplastic fluid viscosity to advantage over the fragile thixotropic gel structures of bentonite. Many of today's polymeric fluids are environmentally acceptable for disposal directly to municipal sewers.

Jan 1, 1989

By Annika Gram, Teddy Johansson, Lutfi Ay

Micropiles transfer tension or compression forces as well as cyclic loads into the ground via skin friction. The Self Drilling Micropiles (SDM) can be utilized for permanent applications. The hollow bar simultaneously acts, as drilling rod, injection tube and reinforcement for the micropile. The SDM system can be used in any type of soil, including unstable soils, without the need for temporary casing. Injecting a cement grout through the hollow steel tendon ensures that the borehole is filled from the bottom to the top. The system is fast, simple, and flexible. The installation minimises noise, vibration, and spoil. There are many potential applications, including foundations, underpinning, resisting uplift, dynamic/cyclic load applications and geothermal installations. The SDM technology were introduced to India first time in the Indian history and utilised in the 4G and 5G network projects. The SDM challenge the traditional cast-in-situ piles in the 4G project and raft foundations in the 5G project. Utilisations of the tensile and the compressive strength capacity of SDM with smart solutions results in noticeably big costs, 17-38 % depending on the soil conditions and time savings. The cost of the SDM solutions was about 40% less than the cast-in-situ piles and raft foundations in an ongoing 5G project. The SDM were used successfully in the liquefiable soil types as well.

Nov 1, 2022

By Brian Langdon

The DRIVEN GROUT PILE was developed in 1989 by DeWitt Construction, Incorporated. This piling essentially consists of a cost-in-place concrete piling that reacts on a steel boot that is driven to bearing. This report will describe the driven grout pile, its background and its installation. The advantages and disadvantages of this system are also discussed. Finally, the results of actual field installations are presented and discussed. BACKGROUND The DRIVEN GROUT PILE was developed out of a need for a low-cost high capacity piling (100 ton) that could be installed with ordinary pile driving equipment. This search was motivated by attempting to incorporate the material economy of an auger-cast piling with the "empirical load test" of a driven pile. Typically, the least cost material for piling in the 100 ton range is concrete (grout). A grout shaft with minimal reinforcement can withstand a compressive load of 100 tons for a material cost in the range of $6.00 to $8.00 per lineal foot. A pipe piling with a capacity of 100 tons has a unit material cost ranging to $13.00 per lineal foot. The marriage of these two advantages resulted in the DRIVEN GROUT PILE. A pile that utilizes the economy of a reinforced grout shaft and has the loading confidence of a driven pile.

Jan 1, 1990

By Lawrence F. Johnsen

In 1989, the Connecticut Department of Transportation authorized the evaluation and design for a reconstructed Route 1 bridge over the Quinnipiac River in the City of New Haven, Connecticut. The project extends from the intersection of Route 1 with East Street, easterly for approximately 3/4 mile to the intersection of Route 1 with Wheeler Street and Stiles Street. The reconstructed roadway will be relatively on-line and widened to provide for four lanes of vehicular traffic and a single-track railway line. The existing bascule bridge and approach spans, which were constructed in 1924, will be replaced by a 270-foot span lift bridge and new approach spans. The lift bridge will have a main lift span weighing approximately 3000 tons, second largest after the Burlington Northern Bridge over the Williamette River in Portland, Oregon. The new bridge will widen the navigation channel to 24 0 feet and provide vertical clearances of 13 feet when closed and 62 feet when open. The project is located in an industrial area. Adjacent properties include retail gasoline sales, auto repair, railroad transport and bulk storage of petroleum. Existing structures include the Yale Boathouse and several retaining walls serving as containment dikes for petroleum storage tanks. The Yale Boathouse, located on the east bank of the river, was constructed in 1909-1910 and is eligible for listing in the National Register of Historic Places.

Jan 1, 1993