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By Maurice Bottiau

When dealing with displacement auger piling, some general and fundamental issues have to be considered, irrespective of the system. More than with other pile types, the interplay between the soil conditions and the design and execution is of outstanding importance. This paper intends to address these issues and to summarize some critical matters in terms of design, execution and control such as : ? Importance of a reliable soil investigation ; ? Summary of the design as it is addressed in Europe for this category of piles ; ? Criteria for a good choice and control of the correct asset of the piles ; ? Importance of the concreting phase; ? Relation between the power and the engine characteristics of the drilling equipment with the final bearing capacity. For each of these issues detailed examples will be given as well as results of load tests and in-situ control during execution.

Jan 1, 2003

By T. Matsui

Many existing bridge abutments on the soft ground laterally move and their many damage examples have been reported. An essential cause for the troubles of the lateral movements may be the lack of examinations for the lateral earth pressure acting on its foundation piles. In the present paper, actual movement condition of existing bridge abutments is first summarized, and then the author establishes a practical and systematical design method for bridge abutment foundation piles, including the examination for the passive pile.

Jan 1, 2010

By John R. Davie

This paper describes the design and construction of two 5.6 MN capacity drilled piers installed to support the main loading elements of a large cantilevered gantry crane. The critical crane columns were located within and at the edge of an existing sheet-pile cofferdam, which had been filled with loose coal slag when it was originally constructed Due to the presence of the slag and the age and questionable condition of the sheet-piles, the drilled piers were installed to provide vertical and lateral supports for these columns. The lateral capacity of the piers was supplemented by two smaller drilled piers and two large spread footings that were linked by a system of grade beams.

Jan 1, 2006

By Prakash Annamalai Rangasamy, Muthukkumaran Kasinathan

"Infrastructure development like elevated expressways, metro train and flyover are required proper foundation system to carry heavy traffic loads/significant lateral load, especially in the presence of hard stratum at shallow depth. Pile foundation under bridge pier system is widely adopted in metro projects where the piles are essentially socketed in rock. However, the drilling in hard rock is a time consuming process and needs heavy machineries which lead to delay in construction activities. In the present study, the influence of free standing height on rock socketing under lateral load is investigated. The experiments were conducted on an instrumented model pile with varying depth of socketing and for varying Lf/D ratios. The experimental results shows the load carrying capacity of the pile increases by increase in Lf/D ratio, where in the case pile without socketing (bearing on rock) is compared with 3D depth of socketing. Thus socketing the pile provides significant benefits on carrying capacity of lateral loads. Embedding the pile into hard strata reduces the lateral displacements substantially compared with pile bearing over hard strata. Form the study, it is noticed that the influence of rock socketing has significant effect in the lateral load capacity. And also, the effect of free sanding height play a major role in the lateral load capacity of the rock socketed piles.1. INTRODUCTIONA substructure carrying heavy lateral load at shallow depth, the structure has to be socketed into hard strata to enhance the efficiency of load carrying capacity. The existing field practice is to socket the end bearing piles in hard strata over a minimum depth of four times the diameter of the pile based on rock classification (IS 14593:1998). Reese (1997) developed p-y curves for analysing drilled shafts in rock under lateral loading, based on strong and weak rock criteria. The proposed p-y curve approach has the ability to simulate the nonlinearity and non-homogeneity of the rock mass surrounding the drilled shaft. Gabr et al. (2002) proposed a hyperbolic p-y criterion based on field tests on small diameter drilled socketed shafts. By considering pile as linearly elastic semi-infinite space and soil as homogeneous isotropic material, Poulos (1971) proposed solution to determine the horizontal displacement and pile head rotation. Poulos (1972) extended this elastic continuum approach to give an approximate solution by considering drilled shaft and pile bearing on rock as fixed and pinned end boundary condition. Zhang et al. (2000) developed a non-linear continuum approach for drilled shafts in a soil and rock mass by considering the effect of soil and/or rock mass yielding on the behaviour of shafts. Randolph (1981) conducted a parametric study on the response of laterally loaded piles embedded in an elastic soil continuum. The study was conducted using the finite element method and the results were fitted with closed-form expressions from which the lateral responses of piles were calculated. The solutions given by Randolph (1981) were expanded by Carter and Kulhawy (1992) from the results of finite element studies on the behaviour of laterally loaded flexible and rigid drilled shafts in rock. Desai and Christian (1977) gave a finite difference program to solve rock socketed problems by considering soil and rock mass as elastic-perfectly plastic. Zhang et al. (2000) verified the proposed finite difference method with existing field test results. Gabr et al. (2002) and Liang and Yang (2006) proposed hyperbolic p-y curves based on filed test results and verified with finite element programs. However the need of field and lab scale experimental studies to validate the existing methods of analysis is necessary."

Jan 1, 2015

By Tomohide Takeyama, Binh T. T. Nguyen, Masaki Kitazume

"Deep mixing columns are widely used to support embankments constructed on soft ground area. Researches on the stability of deep mixing columns were done by some authors when the columns do not simultaneously fail but individually fail at different time. A layer of shallow mixing is proposed to reinforce these columns as a group to increase the stability as well as loading capacity of columned improved area. Two centrifuge model tests were done to observe the effect of shallow layer on reducing embankment displacement as well as on failure pressure of improved ground. Acrylic piles were used as deep mixing columns in the centrifuge tests to avoid unexpected internal failure of columns. The results of centrifuge tests were also simulated by 2D FEM to back-analyze the centrifuge experiments. A good agreement between the centrifuge experiments and the numerical simulations shows that by using a shallow layer reinforcing individual columns, the horizontal displacement at the embankment toe reduces by 60 % and the tilting failure is clearly indicated in columns without shallow layer. Although, no significant failure was observed under the current centrifuge condition, the failure pressure of improved ground was significantly increased with the columns reinforced by shallow layer.INTRODUCTIONCement or lime and soil mixing technique was firstly used in Japan and Nordic countries since 1970s. The technique is used to improve soft soil by increasing its mechanical properties including strength and consolidation characteristics (Kitazume and Terashi 2013). Various researches were done to investigate the characteristics of mixing material due to various factors including types of binder, condition of soil, mixing condition and curing condition (Terashi 1997). On the other hand, many studies focused on the application of in-situ mixing technique such as supporting embankment and underground structure as well as working as the foundation of building and factory (Kitazume and Terashi 2013). In term of embankment supporting, column-type improvement is taken into account for huge applications. Due to loading from embankment, the deep mixing columns tend to fail either external failure (Kitazume and Maruyama 2006) or internal failure (Kitazume and Maruyama 2007). However, the deep mixing columns do not fail simultaneously but instead one by one at different time (Kitazume and Maruyama 2007). Because the deep mixing columns work and fail individually, the strength and stiffness of all columns cannot be mobilized simultaneously. By using a shallow mixing layer fixing the top of deep mixing columns, individual columns may work simultaneously. A combined technology of shallow stabilization and floating-type cement treated columns is used to reduce settlement of a high embankment on soft ground (Ishikura et al. 2007). A research on effect of surface improvement layer on internal stability of group column type deep mixing improved ground under embankment load was reported in the Port and Airport Research Institute, Japan (Kitazume 2011). However, the failure pattern of shallow and deep mixing combined structure has not well studied. This research focuses on the external failure mechanism of the combined structure by centrifuge model tests and back-analyzed simulation using 2D finite element method. The effect of shallow layer on embankment displacement and the yield point of the improved ground is also discussed in this study."

Jan 1, 2015

By Abdelmalek Bouazza, Aamir Mahawish, Will P. Gates

Bio-grouting by means of microbial induced calcite (calcium carbonate) precipitation (MICP) to improve mechanical properties of granular soils has gained much attention in recent years. The biogrouting process offers an alternative and environmentally friendly approach to conventional soil improvement techniques, such as cement. Bio-grouting by urea hydrolysis has been extensively applied to tackle various geotechnical problems. However, it has yet to be applied to improve engineering properties (compressive strength) of a coarse cohesionless material with the aim using it as sand/stone columns within soft and very soft soils. This paper investigates the effect of using light, moderate and heavy biochemical treatments on the unconfined compressive strength (UCS) of coarse sand columns. In addition, the microstructure of the bio-cemented coarse material has been analysed by X-ray computed tomography (XRCT). The experimental results revealed that the UCS could reach up to 200kPa, 1000kPa and 5500kPa for light, moderate and heavy bio-cemented coarse sand columns, respectively. The microstructure investigations showed that the deposited calcium carbonate can be identified using XRCT imaging and can be associated with the gain in UCS values. Various microstructure properties, such as void ratio, dry density and porosity were also identified and compared with the laboratory data.

Jan 1, 1900

By Bastian Hoffmann, Christian Moormann

The paper presents results of an experimental study on the axial load bearing behavior of vibratory driven full displacement piles in comparison with impact driven and cyclic quasi-static installed piles in dense sand. The test setup and the measurement devices used to this end are explained. Subsequently, the results of the axial loading like load settlement curves are shown and the impact of the installation method is interpreted. The results presented in this work are mainly based on three installation methods: test series one investigates axial behavior of vibratory driven piles, test series two describe the same cyclic pile installation process but without dynamic influence wherein a special test setup developed to install the piles cyclic quasi-static in the soil was used. A third test series carried out using the conventional impact pile driving method served the purpose of not only comparing the results against vibratory driving, but also aided in isolating the effects of dynamics inherent to the vibratory driving process.

May 1, 2022

By Serge Borel

An efficient design method is proposed for "piled-footing" and "piled-raft" foundation under lateral loads. It combines the methods used for the displacement design of shallow and deep foundations and takes into account the interactions between the piles and the cap or raft. This method has been applied to previous full-scale tests carried out in the United States. Two groups of six instrumented driven piles were laterally loaded several times: first with the concrete pile cap in direct contact with the soil, and then, after a thin layer of soil had been removed beneath the cap. The proposed method models well the real behavior of piled-raft foundations. It highlights the positive effect of the cap in contact with the soil, which reduces significantly the displacements and the maximum pile bending moments. These are divided by two for the analyzed case histories.

Jan 1, 2002

By Jinung Do, Sung-Ryul Kim, Juhyung Lee

"Model tests have been performed to investigate the vertical, horizontal and cone tip resistances of bucket pile embedded in sand by different installation methods; suction force by pump and jacking force by actuator. Micro-cone penetrometer is used to evaluate the variation of the effective stress inside and outside of the pile after installation. As a result of vertical pull-out test, the jacked pile shows 3 times larger resistance than the suction-installed pile. For horizontal pull-out test, the ultimate horizontal capacity and the slope of load-displacement curve on the suction-installed pile decreases by 22% and 40%, respectively, compared to the jacked pile. In cone penetration test, inside cone tip resistance of the suction-installed pile is about 40% smaller than the jacked pile, which indicates that the effective stress is reduced due to upward seepage of bucket pile in sand by suction force. Therefore, installation methods can affect the behavior of the bucket pile significantly.INTRODUCTIONA suction force occurred when bucket pile penetrates into sandy soils induces seepage flow into the bucket pile so downward seepage near the outside of bucket pile causes to increases the effective stress, while upward seepage inside the bucket pile decreases the effective stress (Mahn, 2005; Fig. 1). The effect of induced seepage causes to reduce the penetration resistance during installation. On the other hand, reduced effective stress can decrease the horizontal and vertical capacities of bucket pile by significant disturbance at the tip of the bucket pile due to the flow net. Due to the complexity and difficulty considering the effects of suction installation, many previous researchers generally have neglected the effect of suction installation in their experiments. Therefore in this study, the effects of suction installation on resistance of bucket pile is examined."

Jan 1, 2016

By H. R. Taber

The extensive subject area "Engineering Practice of Ground Improvement" will be treated within the limitations of space and the writer on the basis of personal practice and experience?largely in Northern California over a period of some thirty-six years and, in "ground improvement" work, with an emphasis on transportation facilities. The stress is on improvement of ground conditions, rather than on techniques of improving inherent earth materials characteristics. "Ground improvement" is discussed as engineering resolution of existing or emergent earth materials defects or deficiencies?that is, as the technically feasible procedures best adapted to achieving a required level of service within physical, economic, social and other constraints. A "required level of service" concept is presented as a tool in evaluation of appropriate ground improvement work.

Jan 1, 2010

By Ali Bouafia

Five full-scale horizontal loading tests of piles carried out by the LCPC in France are interpreted in order to analyse P-Y load-transfer curves. The experimental piles are either bored or jacked into quite homogenous sandy soils and instrumented by strain gauges for measuring bending moments along the pile. Successive differentiation and integration of bending moment profiles have led to derive respectively lateral soil reaction and displacements then to construct the load-transfer P-Y curves. The initial horizontal lateral reaction modulus was derived from these curves and shows linear variation with depth in accordance with Gibson soils profiles. P-Y curves are validated by back-computation of the pile on the basis de these curves and the horizontal reaction modulus was compared to the recommendations frequently used in pile design practice.

Jan 1, 2002

By Willie M. NeSmith

In the Metropolitan Atlanta Area today, augered, cast-in-place (ACIP) piles will be considered on most projects where deep foundation support is required. ACIP piles were first used in Atlanta in the late 1960s, and application began to blossom in the mid-1980s. Current design practice for ACIP piles is addressed in another paper in this conference. This paper describes the evolution of the ACIP industry in Atlanta, and details the use of ACIP piles on major projects in the Atlanta area.

Jan 1, 2003

By Ronald E. Walkington

The U.S. Department of Energy (DOE) is building the world's newest accelerator-based, pulsed-neutron system, called Spallation Neutron Source (SNS). The facility, located in Oak Ridge, Tennessee, is a partnership of six DOE national laboratories - Argonne, Brookhaven, Jefferson, Lawrence Berkeley, Los Alamos, and Oak Ridge. Oak Ridge has the responsibility for managing the partnership and ultimately operating SNS. SNS will provide opportunities for up to 2,000 researchers each year from universities, national laboratories and industry from around the world for basic and applied research and technology development in the fields of materials science, magnetic materials, polymers and complex fluids, chemistry and biology. When completed, this state-of-the-art research facility will provide neutron beams that are 12 times more intense than any other such source in the world. Most of the world's neutron sources were built decades ago. Therefore, it is easy to understand how SNS will provide new research opportunities unavailable elsewhere, and at the same time restore United States leadership in neutron sciences. Neutron scattering research provides valuable information about materials that cannot be obtained through microscopy, X-rays, spectroscopes, or other techniques. The information gained from neutron scattering research leads to improved materials that are used in high-temperature superconductors, powerful lightweight magnets, aluminum bridge decks, jet aircraft, compact and computer discs, magnetic recording tapes, shatter-proof windshields, and many other applications. SNS is like a flashing strobe light providing high-speed illumination of an object and will record the structure of physical and biological materials from plastics to proteins. Because neutrons have no charge, they can penetrate more deeply into materials than do X-rays, light, or electrons and thus reveal bulk structure and properties of materials. SNS will help to understand and "engineer" better materials and the manufacture of better products at the atomic level. Our high-technology society demands new materials that are stronger, lighter, and cheaper yet perform well under severe conditions. SNS, which is designed with the future in mind, will be the leading neutron research facility for many years to come.

Jan 1, 2001

By Donald A. Deardorff

The capacity of a helical pile can be determined analytically using the individual bearing or cylindrical shear methods which are dependent on soil strength parameters and helical bearing area. The torque correlation method is widely used in the helical industry to determine the capacity during installation by monitoring torque during the final seating of the helicals. This method has been shown to be a better predictor of strength than the individual bearing or cylindrical shear methods. To determine capacity using the torque correlation method, the final average installation torque (ft-lbs) is multiplied by an empirical torque correlation factor (Kt, ft-1). Kt values have been well documented for square bar shaft helical products and can vary from about 3 to 20 ft-1 depending on pile geometry and soil type. A default value of 10 ft-1 is generally used for all square shaft sizes and soil conditions. Less research has been done on determination of Kt for round pipe shaft helical products. Studies have indicated that factors which affect Kt include soil type/strength, number of helical plates, helix spacing, helix pitch, depth of embedment, downward pressure (crowd), shaft diameter (round pipe) and load application direction while other studies have discounted some of these factors as inconsequential. This paper reviews past research findings regarding Kt determination for square and round pipe shaft helical products and presents a case history of round shaft helical pile installations in Chicago clay which resulted in much lower than expected Kt values.

Jan 1, 2007

By Adel M. Hanna, Ibrahim M. Mashhour

"Collapsible soil is known as one of the difficult soils, which possesses considerable strength when it is dry and significantly reduced when inundated. In practice, in case of a thick layer, pile foundations are often used to penetrate the collapsible soil to firm soil/rock strata. Inundation of collapsible soil is accompanied by a large and sudden settlement, which may significantly increase the negative skin friction and accordingly the drag loads on the pile’s shaft. Inundation may take place from the running surface-water or raising the groundwater. In case of surface water, the amount of settlement varies, depending on the extent of the wetted zone and the degree of saturation in the soil, while rising groundwater will produce full saturation in the ground and accordingly larger settlement.In the literature, there is lack of reports dealing with the prediction of the drag load on piles in collapsible soils subjected to inundation. This is due to the complexity of modeling collapsible soil analytically. Alternatively; the results of a sophisticated experimental investigation may guide the researcher to develop a model to predict the drag load on these piles.This paper presents the results of a small-scale experimental investigation tailored to measure the soil collapse during inundation and the associated drag load on an endbearing pile’s shaft. Based on the results of the present investigation, the effect of the soil collapse potential and the pressure acting on the soil during inundation on negative skin friction is presented.INTRODUCTIONCollapsible soil is a metastable material, traditionally defined as unsaturated soils that experiences a radical rearrangement of particles and significant reduction of volume upon wetting with or without loading (Bara 1976; Houston et al., 1988). A wide range of soils fall into the category of collapsible soil, including naturally existing types of soils such as: Alluvial flood plains, mud flows, residual soils, colluvial deposits, fans, aeolian or wind-blow deposits sands and silts (loess), volcanic tuffs, gypsum, dispersive clays, loose cemented sands , sodium rich montmorillonite clays (Clemence and Finbarr 1981).Soil wetting and soil saturation may take place as a result of urbanization or natural causes, such as: groundwater level rise, landscape irrigation, broken water pipelines or sewer lines, poor surface drainage, groundwater recharge, cut/fill construction, and moisture increase due to capillary rise. The severity of the outcome depends heavily on the so called collapse potential of the soil, which depends mainly on; soil type, compaction effort, initial water content and stress level at soaking (Houston and Houston, 1997; Ayadat and Hanna, 2007)."

Jan 1, 2015

By Kento Miyamoto, Kazuki Imamura, Takayuki Tanaka

"Global economic development has drastically increased energy consumption in various fields, and CO2 emissions, which are a prime cause of global warming, have continued to increase. Therefore, measures for reduction of the load on the environment have been taken in various areas. Energy improvements of various types of work vessels used for offshore construction might be expected to greatly reduce consumption of fossil fuel, because many of these vessels are larger than land construction machinery and consume large amounts of fuel, which will lead to effective use of resources and alleviation of the load on the environment. However, such efforts are unusual because renewal or newbuilding of work vessels is rare. We developed a work-vessel hybrid energy system based on fuel-saving technology and use of natural energy to promote reduction of CO2 emissions for a large deep mixing barge in 2010. We developed an Automated Generator Start-Stop System, which automatically controls the number of active generators according to power demand during ground-improving work of the deep mixing barge in 2012, thus further improving the work-vessel hybrid energy system. These systems are introduced here.INTRODUCTIONIn recent years, CO2 emission, which is one of the factors of the Global Warming has been increasing. According to the report by National Institute for the Environmental Studies in Japan (2014), CO2 emission in Japan has amounted to 1,276 million tons. The industrial sector in the total emission becomes 500 million tons that is equivalent to 39%. Meanwhile, the offshore Deep Mixing Method requires work vessels mounted with a large power plant (Fig. 1). In sea ground boring, very large load acts on the deep mixing machine, and the large power is required, which results in the increase in CO2 emission. To achieve eco-friendly marine construction, the work-vessel hybrid energy system was developed. Table 1 shows specifications of the deep mixing barge with the work-vessel hybrid energy system."

Jan 1, 2015

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 Z. C. Chen

Based on the analysis of load test data of long floating piles in soft soil regions, the expressions of load-transfer function of pile shaft and tip for soft soils are presented in this paper, and the data of cone penetration test are suggested to use for calculating the parameters of load-transfer functions. For the loads of pile within the range of the working load of pile, the estimated pile stiffness by the suggested method in this paper are in satisfactory agreement with the results of load tests. The current Vijayvergiya's method and Satowa's method also are used to calculate pile stiffness in soft soil for comparison.

Jan 1, 2010

By Shawn Downey

A helical pile with in-situ grouted shaft was used to underpin the existing slab of a large retail store in the Edmonton, Alberta Canada area. The existing structural slab did not have the capacity to support the increased load requirements. The design to upgrade the capacity specified a drilled shaft as the deep foundation to underpin a portion of the slab. A helical pile was quoted as an alternate and ultimately won the bid based on the advantages of the system. After an ASTM D1143 Quick Load Test confirmed the axial compression capacity, 723 helical piles with grouted shafts were installed in 3 weeks underpinning 40% of the 93,000 ft2 (8,660 m2) building.

Jan 1, 2003

By Narong Thasnanipan

Performance of diameter 1.5 m toe-grouted bored pile founded at depth 44 m in sand-gravel formation of Chiang Mai City is presented in this paper. Toe grouting was applied by using tube-a-manchette method. Effectiveness of toe grouting was observed from the standard penetration tests conducted immediately below pile toe through grouting pipes at two stages, prior to grouting and three weeks after completion of grouting. Improvement of pile end resistance by toe-grouting is demonstrated with a series of back analyses carried out by load-transfer method employing hyperbolic transfer function. Construction experience of large diameter deep-seated bored piles in multi-layered subsoil and practical aspects of toe-grouting are also briefly discussed.

Jan 1, 2002