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By Xuhui

Pile foundations are underground projects which are carried out under complicated site conditions, so it is difficult to summarize their characteristic patterns from the everchanging practical pile foundations. In combination with theories, the paper analyses the effects of sound reinforced concrete piles and various types of defective piles on the propagations of stress waves. Through testing on prototype pile models, by use of the transient dynamic method and comprehensive analysis in both time domain and frequency domain, their reflection characteristics and patterns are acquired. In addition, discussions are carried out in combination with some real projects. Our model tests include comparison of large scale pile models of 20X20cm in cross section, 5. 0m in length respectively in air, standard sand, and natural stratum; prototype model tests of digged piles of 0. 7-1. 2m in diameter, and 18m, 30m in length; prototype model tests of bored piles of 0. 6m, 0. 8m in diameter, 12-20m in length. Test results show that no matter in air or buried in medium, the intrinsic characteristics of sound piles and various types of defective piles are fixed. In their time domain waveforms and spectral diagrams, obvious regularity are shown, which proves that the relations between the pile natures and their dynamic responses are fixed, which provide basis for correct judgement of pile soundness and natures of defective piles.

Jan 1, 1991

By Colin Curtis

The City of Manchester is hosting the 2002 Commonwealth Games. A world class Stadium with a 38,000 capacity was commissioned for a site located close to the City Centre. The Stadium location is in an area that was derelict and in need of regeneration and it is envisaged that the Stadium will be the spur for this. The industrial and residential history of the site has left a legacy of buried foundations together with chemically contaminated soils. This Made Ground deposit overlies Glacial Deposits which in turn overlie bedrocks of the Central Manchester Coalfield. Coal mining has taken place from at least 1761 leaving several worked seams and shafts. In order to support the stadium, 1159 conventional augured piles of 600 to 1200mm diameters were used. This paper will deal primarily with the piling operations and testing, but will also discuss the coal seam treatment with respect to piling. A substantial trial pile test programme was carried out together with 11 static load tests on contract piles. The results of the pile tests will be discussed and conclusions drawn.

Jan 1, 2002

By Darrell L. Beddard

The test program information provided for some immediate changes on the upcoming contracts and in contract administration for the I-880 Replacement Project. Plan sheet modifications included changes to the pile data tables showing the actual demand load required for structural stability. The normal class of pile with a minimum load carrying capacity was removed. This provided for substantial pile length reduction at several locations since the structural loading was much less than the predetermined pile class ultimate capacity. New specifications were developed and standard specifications were modified to accommodate the newer foundations, installation procedures and pile acceptance criteria. Current Caltrans specifications require that the Contractor provide bearing capacity at the specified tip elevation. This requirement was removed and pile acceptance was determined by the Engineer. Acceptance criteria was established by the State and was based on. set-up trend over time. Static loading tests were reduced especially in areas where testing was performed on the indicator program. Testing procedures were modified and set-up periods were established before piles could be tested. For the contract near the San Francisco Oakland Bay Bridge (Unit E) the FHWA 1000 tons (8.9 MN) test beam configuration was completely changed. This provided added safety and allowed more tolerance in the pile placement for the testing operations. Indicator piles were added as companion piles to the static loading test piles. These piles were used for restrike events which included collecting dynamic data for calibrating the wave equation analysis with static load test results. Indicator piles also provided quick access for restrike events, where as, the static loading test pile needed modification to perform the restrike operation. Penetration rates were recorded for these operations. Wave equation Analysis Program (WEAP) was used in developing the acceptance criteria. The standard Engineering News Record (ENR) formula in the current Caltrans' Standard Specifications was removed for the contracts. Contractors were required to submit, prior to driving piles, a driveability study for their contract. These studies required discussion of their operations, method of installation, effects of soil set-up, set periods, hammer settings, bearing graphs, inputs to the WEAP program and complete a "Pile and Driving Equipment Data" form. Dynamic monitoring was detailed in the specifications on how the monitoring process was to occur. Set periods were established and restrike events were called out with the frequency of these events.

Jan 1, 1996

By Hyung-Min Kwon

There are a number of methods available that can be used to estimate the bearing capacity of piles that are subject to lateral load, such as the theory of subgrade reaction or the elastic continuum approach. The objective of these approaches is to determine the lateral load corresponding to the allowable lateral displacement of the pile. It is important to select the appropriate soil stiffness when analyzing soil behavior within the allowable displacement of piles because the stiffness of soil is dependent on the displacement of piles. Even though pressuremeter tests can measure the stress-strain behavior within a wide strain range, pressuremeter test results have been utilized to assess only the fragmentary soil modulus based on either semi-empirical correlations or analytical approaches. This study is concerned with a methodology that can estimate the horizontal deformational property, while taking into consideration the nonlinear deformational characteristics of sandy soils. Pressuremeter tests were conducted for 15 cases using a calibration chamber. Reloading curves were employed in the estimation of horizontal deformational property in order to minimize the effect of soil disturbance caused by the installation of the probe. The shear modulus degradation characteristics were estimated from the curve fitting for the reloading curve and from extrapolation using the exponential function. In addition, the difference was taken into account between the stress state around the probe in reloading and that of the in-situ state. A consistent relationship was observed between the maximum shear modulus taken from the suggested method and the bender element tests performed in the calibration chamber, simultaneously with the pressuremeter tests. In addition, the results showed significant concurrence with the well-known empirical correlation.

Jan 1, 2008

By John G. DiGenova

The Allwell Center Ice Arena at Plymouth State University, Plymouth, New Hampshire is located in the flood plain of the Pemigewasset River. To maintain the arena near the level of the surrounding area, foundation design required use of uplift elements to resist hydrostatic loads caused by frequent flood conditions. Soils beneath the arena consisted of very loose to medium dense alluvial deposits overlying thick glaciolacustrine deposits. Bedrock was encountered at depths of 115 feet (35 m) or more. A mat foundation with a sealed building system was developed for the arena to guard against flood events. Several alternatives were investigated to provide uplift capacity for the mat foundation, including the Rammed Aggregate Pier® (RAP) system, driven precast-prestressed concrete piles, driven H-piles, and deep drilled soil/rock anchors. Evaluations indicated that the most cost effective uplift solution was a tension RAP system that developed uplift resistance in the shallow alluvial deposits. A total of 344 55-kip (245-kN) capacity RAP elements were required for the project. The RAPs were designed to resist tensile loads using threaded steel bars. Dual corrosion resistance was provided to the uplift elements by including sacrificial steel and galvanizing the oversized bars and connection plates. A pre-construction test program was conducted on RAP elements drilled to a depth of approximately 25 feet (7.6 m) and installed using various shaft construction procedures and materials. Ten test piers were constructed and six were tested to verify that the piers could resist 200 percent of the design load with measured deflections of less than 1 inch (25 mm). The RAP system also provided improved bearing conditions for the perimeter wall and mat foundations by densifying and stiffening the upper alluvial soils.

Jan 1, 2011

By George Filz, Peter R. Cali

"Unnecessarily restrictive specifications could be limiting the cost effectiveness of deep mixing (DM) applications and therefore limiting use of DM on projects where there are other options. Excessively restrictive standards demanded for strength and permeability certainly increase contractors’ bid prices, and costing the owners and, in the case of Government projects, the taxpayers more than necessary. Yet, lax or ineffective specifications often exist for some vital components of the quality assurance and quality control. In this paper, specifications for key elements of DM design and construction are examined. Recommendations are made to improve and streamline DM specifications to better serve the common objective of constructing a safe and cost effective ground improvement project.INTRODUCTIONSpecifications should, at their best, convey the project design requirements and provide clear direction to the contractor regarding requirements for submittals, materials, execution, measurement, schedule, and other aspects as necessary. The specifications should not be overly conservative, restrictive or ambiguous, and they absolutely should not be deficient in measurement of quality. Guide specifications or recycled sections from previous projects often form the template for new project specifications. But standards that appear in guide specifications or from former successful construction should be critically scrutinized by the designer for relevance before using the copy/paste functions of the specifications writer’s keyboard. Because work does not always go as smoothly as planned, specifications for remediation of non-compliant construction should be clearly stated and enforced. Often, non-compliancy is reviewed after-the-fact and deemed to have met the design intent, indicating that either the specifications were too restrictive or the enforcement too weak.The Federal Highway Administration Design Manual: Deep Mixing for Embankment and Foundation Support, October 2013, was written by a panel of DM expert design practitioners and contractors. Guide specifications are included as Appendix C of the FHWA manual. Those guide specifications have been updated in the deep mixing section of the www.GeoTechTools.org website, and the updated specifications represent the most complete and authoritative compilation published to date. Although the specifications for DM at www.GeoTechTools.org are current and complete, and they portray the state-ofthe- practice, they too must be modified to fit specific DM applications, project needs, and site conditions. The keys to a good set of specifications are to prescribe construction only to the level that is required to meet the design intent, to require appropriate quality control and quality assurance (QC/ QA) activities, and to clearly address remedial measures required for non-compliant work."

Jan 1, 2015

By Terrence R. Udland, Russell D. Call

"Honored with a DFI 2006 Special Recognition Award, the Four Bears Bridge was constructed across Lake Sakakawea and opened to traffi c in September 2005. The very large lake size and severe winter conditions required an effi cient foundation design capable of resisting extreme ice loading and able to be effi ciently constructed in waters up to 90' deep (27.4m).DESIGNING FOR EFFICIENCYLocated in a remote area of North Dakota, the Four Bears Bridge replacement was a major undertaking for the North Dakota Department of Transportation, with dual goals of providing a new structure that would endure a severe environment, while enhancing the natural beauty of the area. Competing bids would achieve the best price for the owner, challenging the design team to creatively solve the engineering challenges unique to the site. Foundations for North Dakota’s new Four Bears Bridge had to accommodate water level fl uctuations of up to 40 feet (12m), along with extreme ice loading and be effi cient in order to be the low cost solution at the time of bidding. All three major criteria were achieved through the use of an effi cient ‘fl oating’ lost precast concrete cofferdam founded on steel pipe piles, which allowed the contractor to achieve the project schedule. The result is an award-winning bridge that is contextually sensitive to the environment. The bridge aesthetics pay tribute to the Three Affi liated Tribes, the Mandan, Arikara and Hidatsa, who reside on the Fort Berthold Indian Reservation, adjacent to the bridge site.The original Four Bears Bridge was located over the Missouri River near Elbowoods, the native grounds of the Three Affi liated Tribes. Construction of the Garrison Dam in the early 1950’s created Lake Sakakawea, a fl ood control project on the Missouri River, and resulted in the area being fl ooded. The bridge, along with many tribal members, was relocated to a site near New Town. The bridge provides the primary crossing of Lake Sakakawea and is a critically important transportation element for the residents of the Fort Berthold Indian Reservation. The relocated bridge had become functionally obsolete and not replacing it would require a detour of 170 miles (274km). The North Dakota Department of Transportation determined that it should be replaced. In order to achieve the most effective solution, the North Dakota Department of Transportation selected a design team responsible for the creation of competing steel and concrete designs that were competitively bid. The design team was led by Kadrmas Lee & Jackson, with FIGG responsible for the concrete bridge design, while Lichtenstein Consulting and Kadrmas Lee & Jackson completed the alternate steel bridge design."

Jan 1, 2007

By Alexander Blatt, Franz-Werner Gerressen

Diaphragm wall technique is usually used to construct structural elements in the ground, commonly used for retention systems, permanent foundation elements or deep groundwater barriers, named Cut-Off-Walls (COW). Recent developments proof, that the technology also satisfies the demands for using the diaphragm wall technique for bulk sampling purposes. Such kind of new ideas required the adaption of equipment and tools for a depth capability never reached before by a trench cutter in any commercial application worldwide. Compared to the development of increasing depths, especially inner-city applications with limited space, demand a minimization of equipment to accommodate such projects. The paper will focus on the developments and solutions generated to fulfill these requirements and will give an outlook to future developments. Further it describes finalized reference projects and will give a general outlook on future trends and developments. The Paper/The Presentation explains as well the installation process in general.

May 1, 2022

By Peter A. Thompson, Richard E. Prust

"The Bangkok Mass Rapid Transit (MRT} Chaleom Ratchamongkhon Line project is the first underground subway to be completed in Thailand. It consists of 22 km (14 miles) of twin-bored tunnels and 18 cut and cover stations constructed within the deltaic deposits that underlie the city. This paper describes the ground conditions, site investigation, including the use of the self-boring pressuremeter and the associated design issues for the construction of deep foundations. The paper also describes a selection of the various deep foundation solutions that were adopted to address particular constraints of the project and the ground conditions, including slurry walls for the cut and cover stations and foundations used for the underpinning of existing structures.INTRODUCTIONThe MRT Chaloem Ratchamongkhon Line Mass Transit Underground Railway comprises approximately 22 km (14 miles) of tunnels and 18 stations. The route is shown in Figure 1.The project was divided into two design and build contracts. The northern section was awarded to the ION joint venture, composed of Italian-Thai Development PLC, Obayashi Corporation and Nishimatsu Construction Co Ltd. Arup were contracted by ION for the design of the northern section. The section comprises 11 km (7 miles) of twin-bored tunnels, nine cut and cover station tunnels constructed within perimeter slurry walls using top down construction methods, and two cut and cover tunnel structures.The majority of the route of the northern contract follows existing highway Rights of Way. This results in the tunnel alignment passing through the foundations of existing highway bridge structures for which a variety of deep foundation solutions were adopted to underpin these structures.An 8-story park and ride building in the Lat Phrao area was also constructed using deep foundations."

Jan 1, 2005

By Franz-Werner Gerressen, Manfred Schoepf

"Diaphragm walls are known as underground structural elements commonly used as retention systems for excavation pits and shafts and permanent foundation walls or elements. It can be anticipated that, with the increasing trend of utilizing more and more underground space to accommodate environmental considerations and urban/suburban development, there will be an increasing requirement for diaphragm walling in even more complex conditions. Complex and/or challenging conditions in terms of ground conditions have a major impact in regards of choosing the right tools for excavation purpose. Complex conditions in terms of space limitations, especially for inner city job sites, require specifically adapted solutions for slurry, spoil, reinforcement and concrete handling and the related logistic to ensure smooth production. Furthermore, one focus will be given to the QA/QC topics of the production process. Real time installation control, data transfer and reporting systems become more and more important ensuring the five dimensions of a jobsite. Therefore, the paper will describe the construction method and the sequence of activities required for the construction of diaphragm wall systems with the focus on the cutter technology. It will describe also the main equipment which will be needed to execute these works under the various conditions INTRODUCTION Diaphragm walls are known as underground structural elements commonly used as retention systems for excavation pits and shafts and permanent foundation walls or elements. It can be anticipated that, with the increasing trend of utilizing more and more underground space to accommodate environmental considerations and urban/suburban development, there will be an increasing requirement for diaphragm wall usage in even more difficult conditions. Of course diaphragm wall can also be used as deep groundwater barriers (Cut-Off-Walls). This market has shown that the demand for these types of walls is reaching more and more difficult soil conditions or required depths which are surpassing the current standard. The trench cutter is the most important tool for performing this work. The trench cutter itself is a reverse circulation excavation tool. It consists of a heavy steel frame with two drive gears attached to its bottom end, which rotates in opposite direction around horizontal axis. Cutter wheels are mounted onto the drive gears. As they rotate, the soil beneath the cutter is continuously being broken up, removed, mixed with the bentonite slurry in the trench and moved towards the opening of the pump suction box. The slurry loaded with soil and rock particles is pumped by a centrifugal pump which is located right above the cutter wheels, up through a hose system up to a desanding plant where the slurry is cleaned and returned into the trench."

Jan 1, 2015

By Fei-chiu Huang

A 17-acre landslide occurred in February 2001, on a slope below Via Bellota in the City of San Clemente, California. Three homes were destroyed and many others placed in jeopardy. The landslide, involving portions of five separate developments, continued to move significantly in the years following. Litigation ensued among the affected parties, and investigations continued through 2007. A mediated repair resolution was ultimately reached among the parties. The agreed upon repair consists of a multi-million dollar stabilization program that included grading, drainage, and structural systems. Part of the construction cost was offset by creating 4 new ocean view custom lots and 20 new mobile home lots. The landslide repair and slope stabilization design involved removal and replacement of portions of the landslide debris and construction of buttress and stabilization fills as well as installation of 74 shear pins in two rows. The shear pins were designed as 4-foot diameter by 50 feet in length and incorporated continuous W30x211 wide flange steel. The shear pins were designed to be installed 25 feet above the slide plane and 25 feet below the slide plane at each location. Construction of the 74 shear pins was initiated in 2008 and completed in 2009. Four-foot diameter holes were drilled by utilizing a truck-mounted, flight-auger-style drilling rig with a 4-foot diameter solid-flight auger. Prior to the installation of the shear pins, an engineering geologist downhole logged strategically selected holes to further evaluate the actual slide plane elevations. The wide flange steel shear pins were then lowered to the desired elevations and encased within 4,500 psi, Type V, 0.45 maximum water/cement ratio concrete. Inclinometers installed within four pin shafts and behind the pin rows indicated performance in accordance with the design. Slight to non-perceivable shear displacement was measured which mobilized the intended capacity at the monitored shear pins. No excessive slope movement was detected at any of the inclinometer locations during or after the construction period. Actual shear displacement of the steel wide flange elements was less than the movement anticipated before shear pin installation.

Jan 1, 2010

By Athul Prabhakaran, Ramin Motamed, Ahmed Elgamal, Milad Jahed Orang, Reza Boushehri

Documented case histories from past earthquakes have exhibited the devastating effects of the liquefaction phenomenon on the performance of buildings that are often presented in the form of excessive settlement of shallow foundations. Example earthquakes include the 1964 Niigata earthquake in Japan, and more recently the 2010-2011 Canterbury Earthquake Sequence in New Zealand, and the 2011 Tohoku earthquake in Japan. All of the listed events comprised several examples of severe liquefaction-related damage to the buildings founded on shallow foundations. Although the liquefaction-induced building settlements have been experimentally studied extensively since 1964 using shake table tests and dynamic centrifuge experiments, studies focusing on cost-effective mitigation strategies are still limited. In this study, the performance of helical piles as a cost-effective countermeasure to minimize the damaging effects of liquefaction-induced ground settlements on buildings founded on shallow foundations is studied. Two large-scale shake table experiments were conducted at the University of California, San Diego (UCSD) to investigate the effectiveness of helical piles in liquefiable grounds. Results from these two experiments highlight a highly improved performance of a shallow foundation supported on helical piles. These largescale shaking table experiments demonstrate the efficiency of using helical piles as a cost-effective countermeasure to reduce the liquefaction-induced building settlement.

By Tae Hwan Lee, Jun-Shin Lee, Daejin Kwag, Sangchul Bang, Gerard T. Houlahan, Moo Sung Ryu

"Geotechnical engineers have been installing innovative, permanent underwater foundation systems utilizing suction buckets for the offshore industry since the early 1980s (Senpere and Auvergne, 1982). This foundation system has been successfully used on numerous and various types of offshore structures in a wide range of environments. Suction buckets have numerous advantages compared to conventional underwater foundation systems. The more notable advantages include easy installation, large loading capacity, low noise and retrievability. The application of reduced water pressure inside the bucket facilitates the installation of the suction buckets, where a suction pump attached at the top of the bucket can accomplish the entire driving operation. Because of this efficient operation, very large suction buckets can be driven into the seafloor, which eliminates the use of a large number of small piles.In Korea, one of the most economical and reliable renewable energy sources is wind power; however, onshore wind power generation has encountered many problems, such as the lack of favorable sites and public concerns about noise and environmental damage. Consequently, offshore wind power generation has attracted increasing attention due to its abundant potential, high efficiency of grid connection, and availability of easy expansion.In November 2011, the government of Korea announced a national offshore wind power development roadmap, which targeted its offshore wind power generation with the goal of becoming one of the top three nations in the world for offshore wind power generation. Korea Electric Power Corporation Research Institute (KEPRI) is the main research arm of the Korea Electric Power Corporation (KEPCO) and conducts research and development on electricity, power generation, renewable energy and other energy-related matters. KEPRI ultimately provides forefront knowledge and leadership to KEPCO with respect to energy and related areas for its near- and long-term needs. Financial support for the overall project, of which the suction bucket foundation system installed for the pilot phase wind turbine is described below, was provided from the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning funded by the Korean Government Ministry of Trade, Industry and Energy"

Jan 1, 2017

By Tae Hwan Lee, Jun-Shin Lee, Daejin Kwag, Sangchul Bang, Gerard T. Houlahan, Moo Sung Ryu

"Geotechnical engineers have been installing innovative, permanent underwater foundation systems utilizing suction buckets for the offshore industry since the early 1980s (Senpere and Auvergne, 1982). This foundation system has been successfully used on numerous and various types of offshore structures in a wide range of environments. Suction buckets have numerous advantages compared to conventional underwater foundation systems. The more notable advantages include easy installation, large loading capacity, low noise and retrievability. The application of reduced water pressure inside the bucket facilitates the installation of the suction buckets, where a suction pump attached at the top of the bucket can accomplish the entire driving operation. Because of this efficient operation, very large suction buckets can be driven into the seafloor, which eliminates the use of a large number of small piles.In Korea, one of the most economical and reliable renewable energy sources is wind power; however, onshore wind power generation has encountered many problems, such as the lack of favorable sites and public concerns about noise and environmental damage. Consequently, offshore wind power generation has attracted increasing attention due to its abundant potential, high efficiency of grid connection, and availability of easy expansion.In November 2011, the government of Korea announced a national offshore wind power development roadmap, which targeted its offshore wind power generation with the goal of becoming one of the top three nations in the world for offshore wind power generation. Korea Electric Power Corporation Research Institute (KEPRI) is the main research arm of the Korea Electric Power Corporation (KEPCO) and conducts research and development on electricity, power generation, renewable energy and other energy-related matters. KEPRI ultimately provides forefront knowledge and leadership to KEPCO with respect to energy and related areas for its near- and long-term needs. Financial support for the overall project, of which the suction bucket foundation system installed for the pilot phase wind turbine is described below, was provided from the New and Renewable Energy Program of the Korea Institute of Energy Technology Evaluation and Planning funded by the Korean Government Ministry of Trade, Industry and Energy."

Jan 1, 2017

By Bill Shea, Gordon King

"For a drainage channel built in San Juan, Puerto Rico, a value engineering (VE) proposal incorporating a secant pile top-down approach saved time and facilitated construction work on the larger flood control project. The channel, at the Bechara Industrial Area, Puerto Nuevo Port Facility and the Puerto Rico Maritime Shipping Authority Dock, was needed to allow drainage of the Rio Puerto Nuevo into San Juan Bay. The port area, one of the busiest in the Caribbean, has over 6,000 ft (1,800 m) of berthing wharves for ocean-going container ships along with over 500,000 sq ft (46,000 m²) of container loading and unloading areas, and is critical to the local economy.Planners wanted to minimize the impact of construction to the port and dock users, and developed a construction methodology and work sequencing that would prevent a complete barrier to port traffic. This plan involved non-contiguous and limited work area that “leapfrogged” along the alignment so as to prevent long barriers to lateral traffic movement across the culvert alignment.After reviewing the project plans and schedule, Morris-Shea Bridge Company (MSB) proposed an alternate design and construction approach that provided significant cost and schedule benefits, and also provided better access for the port and dock users. The alternate VE proposal involved top-down construction methodology and redesigned drainage culvert geometry with two parallel 2,000 linear ft (lf) (600 m) secant walls installed on each side of the culvert. These walls facilitated excavation and formed part of the culvert permanent walls. The result was a significantly reduced required construction right of way that allowed construction work in contiguous areas largely without impact on ongoing port activity. MSB conceived the design concept, and engineered design and construction of the VE alternate secant pile culvert.The project initially consisted of an open channel in the industrial area picking up water from the existing Rio Puerto Nuevo, transitioning to an enclosed culvert through the port and dock areas, and outfall through the existing dock. The base bid construction included three main areas of work:"

Jan 1, 2012

By Marcus Daubner, Karsten Beckhaus, Florian Bauer

The construction industry can and needs to contribute to a more sustainable world. Accordingly, geotechnical works potentially have a significant share. In this context, Bauer understands “sustainable products for geotechnical works” as those that may cause less emissions and increase the sustainability of construction activities. In order to structure the efforts and systematically pursue sustainable targets in the construction sector, and in the specialist foundation industry, the “17 sustainability goals” presented by the United Nations in their AGENDA 2030, can be used for general guidance and for continuous improvement. Benchmarks for relevant economic and social objectives, mainly with environmental aspects, are inevitable. The key parameter to sustainable products for geotechnical works in the focus of this paper is the optimisation of processes on site needed to fulfill the client’s building task, including the selection of technologies and construction methods with minimum environmental impact and minimum carbon footprint.

May 1, 2022

By Sun Gengsheng

Geotechnical properties of soils, usual types of pile foundations, pile capacity, calculation of settlements of pile foundations, usual types of retaining structures for deep excavation, stability analysis of retaining structures and Anti-buoyancy soil anchors in Shanghai.

Jan 1, 1991

By Ryan Law

Ground energy systems are being installed in increasing numbers in the United Kingdom. This is particularly true in London where planning regulations require larger scale developments to provide at least 10% of their entire energy demands from renewable sources. A common approach has been to use the groundwater from the Chalk aquifer as a source of energy. This paper explains the potential long and short term sustainability problems with groundwater based systems sited in central London (or any other urbanized area). It also outlines an approach to site testing and numerical modelling to ensure that the system functions well throughout its lifetime. This approach is then applied to a project located in central London.

Jan 1, 2008

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

By Tony Amis

There is very limited information relating to the potential impact of temperature cycles, outside the variation that occurs naturally, on the behaviour of foundation piles. Such thermal loading occurs when piles are used as heat exchange elements within a Ground Sourced Heat Pump system, in addition to carrying building loads to competent strata. An investigation has been undertaken where a conventional load test has been extended to include a period in which the load is maintained and temperature cycles applied. Instrumentation was installed in the test pile, an adjacent borehole, two of the anchor piles and the heat sink pile in order to be able to develop an understanding of the temperature variation and associated strain changes within and between the various elements. Conventional electronic strain and temperature gauges have been used in conjunction with optical fibre sensors which also measure strain and temperature changes. The results have confirmed the validity of the assumption made in the thermo-dynamic design of the system, the compatibility of the differing measurement systems and differing installation methods for the optical fibres, and initial assessment suggests that the load-settlement response of the pile is not adversely affected by the temperature cycles applied.

Jan 1, 2008