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By A. Mazzucato

This paper presents the experimental results of driving and load tests on an instrumented pile driven into a test pit filled with fine homogeneous sand.

Jan 1, 2010

By Daniel Mageau

Ground freezing has been used for over 100 years to provide shoring and ground water cutoffs for hundreds of projects worldwide, including drilled shafts, tunnels and cofferdams. Typically, these cases involved difficult soil/water problems where ground freezing was likely the only solution. This paper discusses a recent ground freezing project where a frozen soil wall was used for a more conventional problem. A 4-foot-thick frozen soil wall was used to provide shoring and groundwater cutoff for a 20-foot-deep excavation during construction of a cast-in-place concrete storm water detention vault. The site is located along the northbound on-ramp to I405 from westbound SR522 in Woodinville, Washington. The frozen soil wall was successfully formed in soils consisting of till fill over soft organic silt and loose saturated sand in about 3 weeks. The depth to ground water varied from about 4 to 8 feet over the site. The unfrozen soil inside the frozen soil wall was excavated vertically to the frozen soil boundary. The vertical excavation remained open for approximately 2 months with no dewatering required. On one side, fully-loaded dump trucks and other construction equipment operated within 6 feet of the wall face with zero wall movement. This paper addresses the construction issues related to installation and operation of ground freezing shoring. The overall wall performance of the frozen soil wall as well as basic geotechnical design issues are also discussed.

Jan 1, 1998

By Dilip Khatri

Helical pile anchors have gained acceptance over the past sixty years. Most recently they have been commonplace in the 20th century for the power utility industry in anchoring transmission towers, equipment platforms, street lighting, telephone poles, and radio tower applications. They have a strong proven industrial track record in these industries. As the cost of conventional deep pile foundations rises, the practical benefits of helical pile anchors becomes evident as a practical alternative. Noted for their uplift capacity, helical piles demonstrate equally strong compressive capacity as a structural foundation element. This paper summarizes the history, practical benefits, and technical requirements for helical piles. Significant structural testing has been completed at various universities. The practical benefits of these tests are discussed. One case example of proven performance is presented to demonstrate the advantages and disadvantages of helical pile anchors as suitable foundation elements.

Jan 1, 2003

By B. M. Das

Several laboratory model test results for the determination of the ultimate uplift capacity of single and group metal piles embedded in near-saturated clay have been presented. Based on the uplift test results for single piles, the variation of the adhesion factor with the undrained shear strength of clay has been determined, and an empirical correlation for estimation of the adhesion factor in soft and medium clays has been presented. The group efficiency of piles under uplifting load depends on factors such as embedment ratio, undrained shear strength of clay, the number of piles in a group, and the center-to-center spacing of the piles.

Jan 1, 2010

By Junhwan Lee

Pipe piles can be either closed- or open-ended piles. Pile load capacity for a closed-ended pile consists of the shaft and base resistances, while, for an open-ended pile, it consists of shaft, soil plug, and annulus resistances. In order to investigate the pile load capacity of both closed- and open-ended piles, two field pile load tests were performed. For the open-ended pile, the fully instrumented double-walled system was used to separately measure all the components of the pile load capacity. The soils at the test site were predominantly granular soils with relative densities varying from loose to dense with increasing depth. The incremental filling ratio (IFR), which affects significantly the load capacity of open-ended piles, was also measured during pile driving. The test results indicated that the total load capacity of the closed-ended pile was higher that that of the open-ended pile, mostly due to the difference in shaft capacity. The shaft and base load capacities of the open-ended pile were 44% and 20% lower than the corresponding values for the closed-ended pile.

Jan 1, 2003

By R. L. Xu

In this paper, the author would like to point out with figures that the building industry is one of the key industrial sectors of the national economy in China. And in the coming 15 years, the output of building construction will not in the least decrease, but increase. The requirements for building standards, quality, functions as well as physical environment will also be higher along with the incessant development of the national economy and the gradual raising of people's living standard. China is a country with a vast territory and a great, variety of physical characteristics. The topographic and engineering geotechnical conditions are complex and varies considerably from place to place. Although, in recent years, encouraging progress has been made in building construction, there still exist many problems unsolved or even not explored at all, which we have to tackle in the future design and construction of foundations. Also reviewed in this paper are the achievements attained in the past thirty odd years and the challenge we will face in the foundation engineering field in China.

Jan 1, 2010

By Bolestaw A. Ktosihski

Preloading of bored pile bases by grouting is an effective way of reducing foundation costs. The bearing performance of a pile may be considerably improved. Various techniques and devices are used. Preloading of a pile base by a special grouting installation is preferred. The grouting device consisting of a U-shaped grouting tube with sleeves and a plastic membrane, separating the tube from the pile concrete, has well proven in Polish practice. The preloading may raise the pile design loads by as much as 30%, and increase their stiffness by 50%, in suitable conditions. The preloading equalizes the deformability of piles in a foundation or a structure. Examples of the base preloading use and load tests of base grouted piles are presented.

Jan 1, 2006

By S. F. Fu

The Charkhan Salt Lake area of the Chaidamu Basin in West China is characterized by soft super-saline soils with very high contents of soluble salts. From the engineering point of view, these saline soils are saturated, liquid-plastic and moderately to highly compressible lean silty clay and clayey silt. In the natural state, their allowable bearing capacity is only 60-80 kPa. As to the saturated lean silty clay, liquifaction in case of an earthquake of intensity 7 on the Modified Mercalli scale is considered likely. In order to improve the geotechnicai properties of the saline soils, stone colomn stabilization by means of vibroflotation was performed. As the geotechnicai properties of the soils are closely linked with the amount and composition of the soluble salt content, saline water with chemical content similar to that of the saline soils was used as flush fluid in the course of hole-making and column-forming, with a view to keeping unaltered the amount and composition of the salts in the soils and thereby precluding reduction in or loss of their strength. Systematic monitoring on the behavior of the foundation soils before and after the treatment and comparison of the numerical data thus acquired have shown good technical results, testifying to the effectiveness of stabilization of soft superealine soils by vibroflotation. As a result of the treatment, the allowable bearing capacity was increased one to two fold, accompanied by elimination of the liquefaction potential.

Jan 1, 2010

By Chu E. Ho

Current methods of determining jet grout column diameters are highly empirical and site specific, and do not take into account the jet hydrodynamics and soil parameters explicitly. A theoretical model which describes the jet excavation mechanism is introduced in this paper, with the aim of providing an improved prediction tool that can be used in jetting design. The model is based on the assumption that the velocity distribution in the cutting jet is equivalent to that of a free jet with boundaries corresponding to the dimensions of the cavity excavated in the ground. The shape of the cavity formed depends on the erosional properties of the soil and jet expansion is limited by the resistance at the jet-soil interface. The model predicts that the limit of jet penetration is reached when the average dynamic pressure at the jet tip becomes equal to the ultimate soil bearing resistance. The reliability of the model, evaluated using results from four case histories of jet grouting field trials, is within ±15%.

Jan 1, 2006

By A. R. Jambekar

City of Bombay has been developed out of former 7 islands. Landmass of 434 sq.km. of Bombay, started looking inadequate for further growth and expansion of Bombay City. In order to develope twin city of New Bombay, State Government formed fully owned Company "City and Industrial Development Corporation of Maharashtra Limited", (CIDCO) in 1971 and entrusted it with planning and development including social and physical infrastructure of New Bombay.Hence, Trans - Thane Creek area is being planned and developed, to serve as counter-magnet to Bombay. Area of 343 sq.km located on the main land, is fast developing into a satellite community, for India's overcrowded financial capital. Thane Creek, running in almost North-South direction, separates Bombay City from main land and posed a significant barrier, to further expansion of city's sprawling suburbs, until, it was bridged for the first time in 1972. On the basis of traffic study, CIDCO decided to construct an additional road link across Thane creek to cope up with future projected traffic. This bridge will connect Airoli in New Bombay and Eastern Express highway near Mulund. Bridging the vast, exposed tidal Thane Creek, have always posed challenging conditions, during constructions of these bridges. In this paper, case history of deep open foundations provided for Airoli Bridge is presented.

Jan 1, 1996

By Christian Divis

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Jan 1, 2002

By Sugie Prawono

Jacked pile is the only piling system in which the load capacity of the pile, at any penetration depth, could be monitored directly during its installation process. Each installed pile could have a graph of jacking load versus depth of penetration. For safety purposes, the maximum applied jacking load during installation of a pile could be assumed as the minimum load capacity of the pile. This load capacity will increase with time since the drop in soil strength due to the installation process will recover later on. In order to determine accurately this jacking load, a research was carried out by comparing the load capacity of a pile at certain depths to the jacking load recorded during the installation process. The load capacity could be calculated using cone resistance, qc, and local friction, fs, from Dutch Cone Penetration Test. A graph could be drawn of the load capacity against the depth. By applying a correction factor, a, to the data of local friction, the calculated graph could be matched to the graph of recorded jacking load. The a factor is found to depend on the soil type, which is in this case, represented by the magnitude of cone resistance. The soil type is divided into 3 categories according to qc values (qc < 500 Kpa; 500 Kpa < qc < 2000 Kpa and qc > 2000 Kpa). Graphs of the a factor versus depth and a sample of calculation are presented in this paper for easy application.

Jan 1, 1999

By Ron Bromenschenkel

The State of California, Department of Transportation is currently retrofitting a major interchange near the San Francisco area. The project is located in a highly traveled area of Oakland with light rail commuter service near many footings. Over 600 micropiles are being used in conjunction with CIDH piles for footing stabilization. A specially designed Soil Nail pile will support footings for a new light rail utility structure. Pile testing features in this contract serve as points of interest for future foundation designs. The presentation focuses on substructure issues of this incterchange retrofit. Both design and construction considerations will be covered. Design Considerations: ? Project Description ? Structure inadequacies ? Design criteria ? Design contraints ? Retrofit strategy ? Consultant analysis ? Pile Designs and Test Sites ? Contract Specifications ? Construction Plan and Cost

Jan 1, 1998

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 G. G. Goble

Dynamic pile testing is now over 20 years old as a routinely applied tool for evaluating driven pile installation. The first test on a cast-in-place pile was performed more that 15 years ago. The research that produced the method began almost 30 years ago. But, questions still arise regarding the appropriate use of this technique so some review is useful. Today a number of methods including dynamic testing all depending in some way on the application of dynamics are in routine use. First, Wave Equation analysis can be used to predict pile driveability before going to the field. The same approach can be used during driving to estimate the bearing capacity based on the blow count observed in the field. Dynamic measurements, on the other hand, can only be used after pile driving has begun. They offer predictions of pile capacity as well as measurements of hammer, driving system, and pile driving performance characteristics. The first part of this paper will be devoted to discussing how the foundation engineer can use these tools. First, a brief review of what dynamic methods actually do. In Wave Equation analysis a numerical model of the hammer, driving system, pile, and the soil is created by the engineer. The hammer is dropped on the pile and using a discrete, dynamic analysis the motion of the individual pile elements is calculated as a function of time. Of course, input information must be supplied by the program user to describe the hammer, driving system, pile, and soil. In the current state of development, the primary problem in input data is with the hammer performance (efficiency) and the soil description. Research may be able to do a better job with the soil data, but hammer performance will always vary from hammer to hammer and is dependent on the affectiveness of the inspection process. Prior to beginning pile driving the Wave Equation analysis supplies the best available estimate of what will happen when driving begins. It gives an estimate of blow count during driving, driving stresses, both tension and compression in the pile, and for diesel hammers, stroke. The selection of the driving system can be checked with the results of Wave Equation analysis and modifications can be made if required. For example, if the blow count at the required capacity was deemed excessive by the contractor a larger hammer could be tried or if driving stresses were too high changes could be made in the cushion or the hammer selection could be modified. All of these modifications are possible with only the cost of a computer run. The primary questions regarding the accuracy and reliability of Wave Equation analysis at this time is with regard to the assumptions made to represent the soil characteristics and the difficulty in predicting hammer performance.

Jan 1, 1993

By Martin C. Jones

This paper outlines the development of small diameter grouted piling, to deal with foundation problems in difficult soils conditions and in very restricted access areas. A number of applications are outlined to show the way in which these piles have been used over the last sixteen years in Canada. PICKERING GENERATING STATION - ONTARIO HYDRO UNDERPINNING OF SCREENHOUSE - TRASH DISPOSAL AREAS Between 12th July and 29th September 1971, 40 small diameter grouted piles were installed in the screenhouse at Pickering Generating Station. Access was extremely restricted as the screenhouse had been completed and the majority of mechanical equipment had been installed. The two ends of the screenhouse had been built on granular fill which overlies till and shale bedrock and settlements had been observed which it was decided had to be halted even though the rate of subsidence had decreased. Two diamond drills were employed to install 8 inch

Jan 1, 1987

By W. H. Liu

The stability of floors of large drydocks and wagon tipper sheds at coal terminals is an important matter but quite difficult to solve. Anchors can be used to join floors to foundations thus ensuring the stability of floors by the self-weight of floors and the pull of anchors. In this paper, the author describes the structures and types of the anchors used in the floors of the drydock in Beihai Shipyard and the wagon tipper shed at Shijiu Port, both in Shandong Province China, the determination of bearing capacity of anchors in rock bed of highly weathered granite, the comparison between prestressed anchors and non-prestressed anchors, the construction technology of anchors and the analysis of field experimental data.

Jan 1, 2010

By B. N. Hira

A multistoreyed residential complex was at the penultimate stage of construction by ONGC at Nazira, Assam. The site was situated at high earthquake zone. The subsoil was very weak and contained soft to medium clay with water table almost at the ground level. The bearing capacity of soil was quite poor particularly with predicted settlement beyond permissible limit. In this situation, the conventional shallow and deep foundations were found uneconomical and ground improvement with granular piles was considered as the viable solution. ONGC approached the Central Building Research Institute with the request to design granular piles along with R.C.C. foundation and other suitable cost effective measures. CBRI collected relevant geotechnical informations and supplimented the data by conducting field tests at site and laboratory tests at Roorkee. Rational design of 30 cm dia. and 5.00 meter deep granular piles were suggested with isolated and combined RCC footings over the reinforced soil. In addition to several structural and geotechnical advantages, the granular pile foundation provided considerable economy in the cost of construction. The paper presents the salient geotechnical and structural informations of the challenging project and provides the design details of the innovative granular pile-system. It also furnishes the design approach of the RC footings and other elements of the foundation.

Jan 1, 1996

By K. [Muthukkumaran

An extensive program of laboratory model tests was undertaken to study the effect of slope on p-y curves under passive loading in dry sand. The paper concerns the method developed in a series of laboratory model tests to experimentally determine p-y curves. Bending moment curves are differentiated by using curve fitting method of cubic polynomial function. The study includes effect of slope angle and relative density on bending moment and non-dimensional p-y curves. The non-dimensional p-y curves for piles on sloping ground under passive load are developed modifying API method by including a Reduction Factor (R) using the experimental results.

Jan 1, 2006

By James A. Schneider

The evolution of the American Petroleum Institute (API) design method for axial capacity of driven piles in siliceous sands is explored, and complemented with an overview of how changes in offshore site investigation practice have increased the level of knowledge with respect to vertical variability of soil characteristics. Increased use of the cone penetration test (CPT) provides near continuous profiles of soil type and strength which can be used in calculation methods that address variation in local shaft friction rather than the API method which seems to have initially been based on observations of average shaft friction in relatively uniform sand deposits. Development of a formulation for CPT correlations to axial pile capacity in sand is discussed, along with implications to existing factors of safety used in routine design.

Jan 1, 2006