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By Timothy D. Stark

Jet grouting has increasingly become a ground improvement technology used to address seepage concerns and provide strength improvement to soils underlying dams. The technique of jet grouting uses high pressure/volume jet fluids to erode existing soil, evacuate some or most of the soil, and mix the remaining cuttings with cement slurry to form soilcrete. While considered a useful technology, this paper discusses some of the problems that can develop while jet grouting in or below a dam with an operational reservoir and seepage condition. Jet grouting experience at Tuttle Creek Dam indicates concerns with respect to ground fracture; spoil return, column diameter consistency, and homogeneity of resulting soilcrete. Recommendations are presented to increase monitoring of downhole parameters during jet grouting to better understand the downhole pressures and soil response during jet grouting.

Jan 1, 2012

By Raffaella Granata

The paper deals with the remediation of two areas formerly utilized for the disposal of hazardous wastes in a petrochemical plant. The works, designed on the basis of the criteria of maximum safety and minimum environmental impact, consisted in the confinement of the contaminated soil and groundwater within surface caps and perimetrical cut-off walls embedded in the underlying clay layer. The cut-off wall is 0.8 m thick and has a maximum depth of 33 m: it was designed to guarantee, as a minimum, the level of safety for a landfill for hazardous wastes, in accordance with the applicable National Standards. It was constructed with self-hardening mud and with the installation of an HDPE geomembrane. The HDPE liner of the cut-off wall was then sealed to that of the capping to obtain the complete encapsulation of the contaminated soil. A system of piezometers allows the monitoring of the cut-off efficiency measuring the fluctuations of the groundwater table and testing the chemical contents. Some wells installed within the contaminated areas will contribute to guarantee the full efficiency of the system in case of state of emergency, controlling the water-table level inside the confined areas.

Jan 1, 2006

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 Heinz Brandl

Box-shaped pile and diaphragm wall foundations have proved suitable for transferring heavy loads of bridges, power plants, tanks, towers or other buildings in a concentrated form into the ground. The bearing-deformation behaviour and the earthquake resistance of such "box-foundations" are superior to those of conventional pile groups. The reason lies in the reduction of lateral soil displacement and in the composite effect between concrete elements and the enclosed soil. The paper describes results of comprehensive model tests and in situ measurements, theoretical aspects and case histories.

Jan 1, 2002

By Hui Yongning

This paper presents a simulating test of constitutive relation of soil anchor in laboratory and puts forward a new plastoelastic mechanical model, on which a new calculating formula of elastic and plastic limit bearing capacity for soil anchor is suggested and two engineering projects verify that this method is adaptable.

Jan 1, 1991

By Christopher J. Pacitto

This paper presents a case history of an engineered, monitored, and tested program that provided an effective and satisfactory basis for the completion of pile foundations for Twin Dolphins 1 at La Peninsula Condominiums located in the Isles of Capri in southwest Florida, U.S.A. An 8-story building (withl-story parking underneath) along with recreational facilities (such as a swimming pool and tennis courts) had been planned for final construction. Following an evaluation of various foundation alternatives, a precast prestressed concrete (PPC) pile-supported system was selected. The building foundations were designed for pile capacities of 445kN (50 tons) and 890kN (100 tons) in compression and 133kN (15 tons) in uplift. A test pile program was performed to provide site-specific pile driving data, verify design assumptions, determine production pile lengths, and evaluate pile driving criteria. A total of 24, 356 mm (14-in.) square, 19.8 m (65 ft) PPC concrete piles were driven and dynamically load tested utilizing a Pile Driving Analyzer (PDA) within the building limits. Dynamic monitoring during probe pile installation and restriking was performed to estimate the ultimate capacity of the piles and to evaluate driving stresses during installation. CAPWAP analyses were preformed on PDA data to better estimate pile capacity, resistance distribution, and predict pile freeze (increase in pile resistance with time) and thus optimized the production pile lengths. Upon completion of probe pile installation, 12 of the probe piles were tested using the Pile Echo Tester (PET) function of the Pile Integrity Sonic Analyzer (PISA). PET testing was performed to evaluate the integrity of piles which had exhibited high driving stresses during PDA testing. Information gathered during the probe pile driving program was effectively utilized as part of the overall quality control program to install a total of 539 PPC piles (including 24 probe piles) within the building limits at the project site to depths ranging from 9.1 to 19.8 m (30 to 65 ft) below the existing ground elevation as part of the foundation support system. Prior to installation of probe or production piles, a termination criterion was established using 1-dimensional wave equation analyses in addition to the design pile embedment requirement. The predicted pile capacities compared very well with the capacities from the CAPWAP analysis for probe piles. Use of geotechnical instrumentation and PDA assisted technology enabled each foundation support element to be constructed to its optimum capacity and at optimum cost. Furthermore, by using PDA the consultant was able to quantify a difficult to measure geotechnical phenomenon termed "pile freeze" which eliminated costly overdriving and unnecessary splicing of piles.

Jan 1, 2002

By P. Ventura

Reliability of the liquefaction analysis is based on data plotted as by piezocone, as by deep vibrocompactation monitored tests. The negative porewater pressure, re lated to hydrostatic value, recorded by piezocone, is a good marker of the absen ce of the liquefaction. Systematic measures of the ground settlements, inside the vibroinfixed steel pipe, allow to locate the liquefable strata with loose density. Experimental study of the combined soil improvement by stone columns is carry out in particular in sea bed. The interaxis of the columns for the best efficiency is valued as of the vibrocompactation, as of the drainage effects, especially during earthquake.

Jan 1, 1989

By Mark R. Svinkin

Construction-induced vibrations may be detrimental to adjacent structures and sensitive electronics operating nearby. Construction vibration sources have a wide range of energy and velocity, as a function of time, transmitted on the ground. Analysis of existing methods for predicting ground and structure vibrations shows that empirical equations provide calculations only of amplitudes of vertical soil vibrations with insufficient accuracy. This paper presents the application of the impulse response function concept to solve the geotechnical problem of predicting ground and structure vibrations before installation of vibration sources. Impulse response functions reflect real behavior of soil and structures without the investigation of soil and structure properties. A procedure is presented to compute predicted ground and structure vibrations. Good agreement is found between predicted and measured records.

Jan 1, 1999

By Xiong Houjin

In the excavation works of some deep foundation pits within the boundaries of Guang­dong Province of China, though some measures, such as steel sheet piles, diaphragm walls, etc. were taken to protect the walls, the construction of the excavation works was often accompanied by damage of buildings and public facilities, surface settelment. sand boil and collapse of piles. When these happened, only chemical grouting could be used as the most efficient measure for rushing to deal with or rescue the emergencies. Besides, the application of chemical grouting protection wall technique also palys a very important role under the geologic conditions of the coastal areas of Guangdong Province, when applied in the mucky oystershell layer wealthy in water and the deep mud layer, it can not only achieve good results, but also reduce the cost significantly. In this paper, we discuss the water-tight and earth retaining functions of chemical grouting protection wall in weak formation, and introduce the applicable ranges of chemical grouting protection wall in the excavation of deep foundation pits. Some technological principles and design considerations of the construction of chemical grouting protection wall are presented. Different types of protection wall are also introduced.

Jan 1, 1991

By S. H. Miller

Biodegradable hydraulic fluids can save tens or hundreds of thousands of dollars in fines and clean up costs in the event of a hydraulic fluid leak or spill. When properly selected, applied, maintained and monitored, a biodegradable fluid will have a long useful life and will protect equipment as well as or better than conventional petroleum based hydraulic fluids.

Jan 1, 2000

By J. Nakayama

Construction of foundation piles or diaphragm walls through rocky or boulder containing formations has been long-standing difficulty. It has been widely understood that the down-the-hole hammer is the most capable mechanical means but is restricted in drilling diameter by the unavailability of drillhead sufficiently large diameter and the difficulty of disposal of cuttings. A great number of submersible motordrills have been used for the construction of cast-in-place piles and diaphragm walls and the reverse circulation system employed has demonstrated its advantage of the prompt removal of cuttings. The development of multi-head down-the-hole hammer drill combined with reverse circulation system presents a powerful engineering choice for those "hard-to-drill" ground formations. This paper will introduce the features of the system and some actual operation results in the foundation engineering through those hard rocky ground formation in some countries.

Jan 1, 1989

By Wolfgang G. Brunner

A 3800 m long temporary water-retaining dike has been constructed under extreme conditions in the harsh northern climate to enable two of the kimberiite pipes at the Diavik Diamond Project reserve to be mined using open pits. The Diavik Diamond Project is located on East Island at Lac de Gras in Canada's Northwest Territories, approximately 200 kilometres south of the Arctic Circle. The dike which has been constructed in up to 25 m deep water from crushed granite quarried from the site projects into Lac de Gras encircles the first two of the kimberiite pipes to be mined. An 800 mm wide diaphragm cut­off wall constructed of bentonite, cement and crushed rock, totalling 33,000 m2, and a two-phase jet grouted curtain wail at its base, totalling 8,400 m2, have been installed through the dike and underlying till foundation into bedrock. The cut-off is designed to minimise water seepage from Lac de Gras through the dike. In order to ensure that the dike had adequate internal stability and diaphragm wall construction could proceed safely, the crushed rock fill material dumped into the lake was first compacted by TR 75 deep vibrators. In 2000, Bauer Maschinen GmbH of Schrobenhausen, Germany were awarded the contract for the supply of all specialist foundation equipment required on site and for providing technical support to the Canadian main contractor Lac-de-Gras-Construction throughout the construction of the cut-off walls during 2001 and 2002. Installation of the cut-off walls was completed in July 2002, three weeks ahead of schedule, and dewatering of the inner dike areas commenced just 5 days later and has continued throughout August and September. After completion of extensive testing of the diamond recovery plant, the mine is scheduled to go into full open pit production in February 2003.

Jan 1, 2003

By John Lemke

Current practice for monitoring static pile load tests commonly consists of measuring load and displacement at the top of a pile. This is typically accomplished by monitoring dial gauge movements, line pressure of a hydraulic jacking system, and electronic load cells on occasion. While this testing approach provides useful information for one boundary condition (the top of the pile), a system that measures movement and/or strain along the entire length of the pile can provide additional useful data that can be used to refine pile design. Automated data acquisition systems provide the essential ingredient that can integrate these types of sophisticated instrumentation devices into a standard pile load test program in a cost effective way. This paper provides a general overview of pile testing instrumentation and describes a newly developed chain of instrumentation modules that can be embedded in a pile to gather additional testing information. The new system can measure forces and movements within the test pile synchronously with measurements at the pile top, and the direct application of this system to axial and lateral pile testing is illustrated. This is particularly relevant to the design of ACIP and drilled displacement piles since determination of the reinforcement cage length is important from the standpoint of both seismic design and foundation cost.

Jan 1, 2002

By Drew Floyd

Five full-scale pile load tests were performed on pairs of PZ-22 sheet piles installed with a vibratory pile driving hammer. The sheet piling was installed in several locations in soil generally consisting of miscellaneous granular fills overlying soft organic silts, inorganic silt interbedded with sands and gravels, very dense glacial till and shale bedrock. The test program also included the use of tip tell tales to determine what capacity could be attributed to tip resistance and skin friction. During the design phase of the project, it was assumed that the capacity of the sheet piles driven with the vibratory hammer could be correlated with the rate of penetration. The correlation between vertical capacity and rate of penetration would be used as a basis for determination of a driving criteria from driving the production sheet piling. The sheet piling load tests demonstrated that it was not possible to correlate the capacity of sheet piling driven with a vibratory hammer and the rate of penetration. It was also demonstrated that the capacity of the sheet piles was directly related to the density of the soil at or just below the tip. The results also tend to agree with empirical equations provided by Meyerhof (1976).

Jan 1, 1989

By Gregory J. Canivan

Three test pile programs were conducted in Charleston, South Carolina to evaluate differences in bearing resistance due to installation methods. The tested piles were installed with impact hammers and vibratory drivers through soft clays and/or loose sands into the Cooper Marl, a stiff calcareous marine clay or silt. Piles driven into the Cooper Marl experience significant capacity gain with time following initial installation due largely to pore pressure dissipation. Pile size and pile type were both known to affect pore pressure generation during installation and subsequently the capacity gain with time. The test programs were primarily conducted to optimize pile design values and construction methods with regard to trestle construction but the results also contribute to the understanding of driven pile behavior. High strain dynamic testing was performed on several open-end pipe and H-piles. The measured difference in long-term bearing capacity of the H-piles as a result of the two installation methods was negligible, while the short-term bearing capacity of the pipe pile was larger when the piles were installed using impact hammers. The lower short-term resistance in the vibratory driven piles is attributed to larger excess pore pressures generated during installation compared to those generated during impact driving.

Jan 1, 2002

By Peter Jackson

The dewatering of the large construction pits required for major infrastructure projects often has a significant impact on the environment. This is particularly so in urban areas and where groundwater resources are of interest. These environmental impacts are inter alia, groundwater lowering and the consequent effects such as settlement and deterioration of timber foundations, together with the impact of the dewatering on the groundwater quality. In order to minimise the environmental impact of the dewatering, the quantity of water to be abstracted and the amount of groundwater lowering in the surrounding area must be minimised. This paper describes the measures that have been taken on the Copenhagen metro project to achieve the objective of minimal environmental impact whilst still carrying out a major dewatering scheme.

Jan 1, 2000

By Y. Duraisamy

This paper presents the compressibility of tropical peat reinforced with cylindrical cement column. When a cement column installed vertically in peat, its compressibility was reduced because of the hardened skeleton matrix formed by cement particles bonding with adjacent soil particles in the presence of pore water. The effects of diameter, number of columns and cement proportions in cement columns on the compressibility have been investigated in this study. The results indicated that compressibility index Cc and Ca decreased with the increase in diameter of the cement column. Specimens with 45 mm and 60 mm diameter of cement column were cured for 28 days, after which they were subjected to Rowe Cell Consolidation test. Based on the results obtained, it shows that cement columns can successfully reduce the compressibility of tropical peat.

Jan 1, 2007

By John P. Turner

The behavior of tieback retaining walls depends on many factors, including soil properties, groundwater conditions, construction sequence, spacing and stiffness of tiebacks and soldier piles, tieback loads, and others. The primary design considerations for tieback walls are 1) adequate stability and 2) limiting wall movements. Traditional design methods rely on apparent earth pressure diagrams and experience to predict the forces which must be supported by the tiebacks to provide adequate stability. The required soil properties depend upon whether the soil is sand, soft clay, or stiff clay. Design to limit wall movements is more difficult and the usual approach is to design the wall with an adequate factor of safety for stability and then evaluate wall movements during construction through the use of load tests on individual tiebacks and monitoring of wall movements by optical surveying, slope indicators, and extensometers. If excessive movements are likely to occur, it is often not known until construction is well underway. This approach is reflected in the fact that few tieback walls fail due to a lack of adequate stability, while most litigation involving tieback wall performance is related to excessive movements. Much progress has been made in recent years in methods for predicting the movement of all types of insitu retaining walls (Clough et al. 1989, Clough and O'Rourke 1990). These methods are based upon both experience and analytical methods. This paper reviews the methods currently available for evaluating both the stability and movements of tieback retaining walls. Case histories involving excavations constructed in the downtown Seattle area are used to evaluate the applicability of the available methods to Seattle conditions and to illustrate the importance of soil behavior in tieback wall performance.

Jan 1, 1990

By Bill Starke

The acceptance of AugerCast piles in Canada has been limited. Many engineers are apprehensive about the quality of the piles produced by this method. However, advances in the sensing instruments and computer technology can now provide satisfactory levels of quality assurance. Post construction tests such as the sonic echo method can give an indication of pile shaft integrity. Computerized monitoring of the pile installation process is an immediate and more positive method of quality assurance. The computer continuously measures and records the parameters which indicate the quality of the pile. If these parameters do not indicate a satisfactory pile, it is replaced before the concrete hardens. Computerized monitoring of the installation process is another tool available to the engineer. The data from this system analyzed with soil borings, site inspections, and possibly sonic tests can provide the engineer with enough information for pile certification.

Jan 1, 1997

By Tracy Brettmann

A new method for estimating ground vibrations caused by pile driving was developed as a result of a vibration monitoring program performed for a large pile driving project. The method is accurate, rational and theoretically based starting with energy actually transmitted to the pile (not the rated or operating hammer energy). This energy is then assumed to be transmitted to the soil in the form of surface waves that attenuate from both geometric and material damping. The main input parameters for this method include the energy transmitted to the pile and the dynamic properties of the soil (wave velocity, material damping, and unit weight). In this study we concurrently measured both: (1) pile driving of 14-in.-square, 65-ft-long precast concrete piles with a Pile Driving Analyzer?, and (2) vibration levels at various distances away from the piles during driving. A geotechnical study for the site was also performed that included measurement of the dynamic soil properties using both crosshole and seismic cone testing. This paper presents the data obtained from the study and compares the results to the values estimated using this new method. Vibrations from pile driving is a serious matter that impacts virtually every pile driving project. It is important that accurate methods for estimating ground vibrations be available to engineers and contractors.

Jan 1, 1999