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By Z. Q. Wang

The author is trying to clarify the existing problems in designing and laying out dynamic consolidation for soft ground improvement. Field testings and observations including vibrational parameters, pore pressures, stereoscopic photogrammetry etc. were run in order to trace the real behaviour of ground movement during tamping. It is believed that all the data got from the field work are rather informative and illustrative than that from theoretical modelling in the laboratory, thus some highlights relating effective thickness of compaction, maximum spacing between compaction points, number of blows for optimum tamping and seismic attenuation for environmental consideration are given.

Jan 1, 2010

By Alan Christopherson

Nearshore construction projects often require installation of steel piles and specific methodologies of installing piles may adversely affect nearby species of concern. Water is an uncompressible medium which allows for easy transmission of energy through the water column. Energy transmission through water depends on the following factors for pile driving: 1) direct contact of the pile and the water; 2) the depth of the water column; 3) the size of the pile; 4) type of hammer; and 5) the energy of the hammer. Seasonal restrictions are usually the best practicable alternative for reducing habitat impacts when pile driving activities may adversely affect the species of concern. When seasonal restrictions are not practical other options need to be evaluated, including mitigation and noise attenuation devices. The broad array of mitigation options will not be discussed as part of this presentation but instead will focus on noise attenuation technologies. Dewatered cofferdams can be effective noise attenuators as they eliminate direct contact of the pile with water while driving. Also, introduction of a compressible medium, like air, near the energy source can provide sound energy attenuation. An unconfined bubble curtain is relatively inexpensive but is not effective in tidal marine projects or rivers and may have unacceptable secondary effects. Secondary effects must be evaluated as these can increase exponentially for larger projects. Secondary effects to the environment include air quality degradation from air compressor use, transportation costs for fuel and equipment, and the potential for injecting oily compressed air into the water column. The confined bubble curtain works well in nearly all environments. It usually is more expensive initially, relative to an unconfined air curtain, but there is less potential for harmful secondary effects. Generally, seasonal restrictions will be adequate to protect species of concern. However, there are conditions in which mitigation or one of the sound attenuation options should be utilized. Site specific factors, including the amount of energy being imparted into the environment, sensitivity of the species of concern, current, accessibility, length of time needed to complete the project, and the cost of the sound attenuation, should be factored into the permit evaluation.

Jan 1, 2013

By Emad Farouz, Ehab S. Shatnawi, Charles Winter

The increasing demand for small deformations and high-capacity drilled shafts without enlarging drilled-shaft diameters has motivated the development and increased use of a base grouting (BG) technique. This technique has been demonstrated to improve drilled-shaft axial capacity, especially for shafts tipped into loose cohesionless soils. To date, there are a couple of documented design methods for estimating the axial geotechnical resistance of base-grouted shafts. However, there is no or lack of research that addresses the lateral response of such shafts. A base-grouted drilled shaft test program was carried out during the design phase of the Wisconsin I-94 Zoo Interchange reconstruction project. The test program included installing and testing one base-grouted shaft and one ungrouted shaft under both lateral and axial loading. Based on test results, it was concluded that the lateral behavior of the BG drilled shaft is significantly stiffer than conventional drilled shaft . Hypothetical method was developed to account for potential increased, however, the method should be verified with more lateral load test.

By Ting-Wei Wang, Yung-Wen Chen

Artificial ground freezing is commonly used globally during excavation of shield tunnels and for groundwater control. It is a special construction method for temporary ground improvement that involves introducing coolant into underground pipes to freeze water in the soil. The frozen soil is cemented together as a result to form a frozen wall, which provides high strength and low permeability. Once the thickness of the ice wall reaches design requirements, underground excavation can be conducted with the coolant removed afterward to return the soil to its original state. This technique is cost-effective in scenarios where complete groundwater cut-off and excavation support are required; where work is deep underground and faces difficult ground conditions and where access restrictions limit the use of other displacement-type ground improvement techniques. Due to the demand for shield tunnel construction for utilities in Taiwan, ground freezing has become an important soil stabilization method there. In this article, we will share two brine freezing case studies and an in situ liquid nitrogen experiment that was conducted to develop this technique.

Feb 1, 2022

By Morgan NeSmith

The Port of Palm Beach is a full-service landlord port in Riviera Beach, Florida. The port and its tenants process more than $14 billion in commodities. About 80% of these are exports, which makes the Port of Palm Beach one of only 16 "Export Ports" in the U.S. More than 2.5 million tons of cargo move through the port every year. Ozinga, a fourth-generation family- owned construction materials company, has supplied ready-mix concrete for commercial, residential, public works, landscaping and excavation projects from several of its Florida locations. It planned to build a one-of-a-kind cement storage facility to receive and store international ship- ments of cement for transport to other facilities for the production of ready- mix concrete. Dome Technology, of Idaho Falls, Idaho, designed and constructed the 125 ft (38 m) diameter storage facility. The design and working volume of cement for the facility was just under 27,000 cu ft (765 m3). The design loads required to be supported by the foundation system are shown in this table:

Apr 1, 2023

By George Onorato, Giovanni Bonita

Deep soil mixing (DSM) has now become a ubiquitous ground improvement technique across the globe for producing soil-cementous materials for many types of complex civil and environmental applications. In the field, the cementation bonds of the soil-cement materials are formed under a confining stress conditions; however, these conditions are generally not considered as most wet grab specimens are cured and tested under ambient atmospheric conditions. This has led to an underestimation of the engineering and mechanical properties of the soil-cement mixed material. This paper presents the preliminary findings of the effect of confining stresses on the mechanical properties of soil-cement mixed samples. This paper discusses the specialized field techniques used for modeling confining stresses during curing and presents the preliminary findings from different soil types. The findings indicate a strength increase within samples cured under a confining stress relative to nonconsolidated samples. The magnitude of the strength increase also appears to be different for different soil types. Finer-grained soils appear to exhibit a larger relative strength increase with confining stress relative to predominately granular soils.

By Cem Akgüner

The displacements of axially loaded single piles are analyzed with an approach based on elasticity. Young?s modulus and Poisson?s ratio of the soil encompassing a pile are the unknowns required as input to obtain predictions based on the elastic method. Attention is directed towards Young?s modulus because the range and variability of Poisson?s ratio is not significant in displacement calculations. A database of axial pile load tests established for the California Department of Transportation (Caltrans) is investigated. All of the tested piles were driven into the ground. Measurements of displacements and loads were made only at the top of the pile. First the magnitude of displacements is determined up to loads that are half of the failure load measured from pile load tests. Various correlations for Young?s modulus are then employed to determine how accurately each predicts the actual measured displacement. The chosen correlations utilize the routinely available parameters of laboratory triaxial undrained shear strength for cohesive soils and standard penetration test blowcount for cohesionless soils.

Jan 1, 2008

By Daniel Levacher

Pile load tests in site require extensive means of action and time. To get outstanding tests, the environmental test conditions must be perfectly known and acceptable. They concern the support installation, the loading, the access and instrumentation site conditions and the economical aspects. In particular cases as offshore areas, the load tests are not feasible. Moreover the variability of soil characteristics limits the interpretation results at the considered tested site. The use of centrifuge modellling offers an other way to study the loaded pile behaviours. Centrifuge tests lead to parametric approaches which constitute for geotechnical engineers an important data base tor recommendations and design codes. To accurately simulate pile behaviours by checking similitude laws linked to the studied problems, the installation of model-piles must be also representative of the in-situ piles. Driven piles account for a large part of the piles installed through the world, mainly for offshore or harbour constructions. So, to explore driven pile problems by centrifuge tests, miniature pile driving hammers must be developed and tested under macro-gravities. The paper describes two types of these ones in details. They are commonly used at the centrifuge centre of the Laboratoire Central des Ponts et Chaussées - (LCPC) - [Réf. 1] for different deep foundations researches. Performances and limitations are given for both miniature pile drivers and some results from their use are presented to illustrate the suitability of these apparatus.

Jan 1, 1996

By Peter Deming

"PART 1 OF 2INTRODUCTIONSlurry trenches are the least cost hydraulic barrier available, if the excavated spoils can be recycled into backfill. As such, slurry trenches are constructed where possible, sometimes at high risk. Slurry trenches are also used to install biopolymer drainage trenches, which have a low safety factor because the biopolymer slurry weight is marginally greater than the weight of water. In marginal ground the construction risk falls to both the Owner who designs and asks for the construction, and the Contractor who manages the work and promises to complete the project successfully. This paper discusses design and construction of slurry trench barriers in marginally stable ground and where groundwater chemistry invokes the need for slurry management details to obtain proper backfill placement.As a designer, Mueser Rutledge Consulting Engineers works for both Owners and Contractors. We are usually able to convince Owners of their responsibility for design detailing in order to obtain a working final product and to obtain reasonable bids from Contractors by disclosing construction needs and designing to reduce the contractor’s exposure. We often work for Contractors to produce designs which result in successful construction in projects where the Owner’s engineer places the responsibility of design and construction on the Contractor.This paper is intended to inform both Owner and Contractor audiences of resources which are available to reduce the risks of trench collapse in difficult ground conditions. We hope it serves this purpose.DESIGNSubsurface InvestigationsSubsurface conditions should be defined by borings focused on definition of the soil profile and soil design parameters. After general subsurface conditions are defined, barrier borings should be drilled along the final alignment.Definition of Soil Strength and CompactnessCompactness of sand and gravel strata should be defined with Standard Penetration Test N-values. The shear strength of cohesive materials should be defined by laboratory testing. Silt and fine sand strata with little cohesion should be investigated using mud rotary techniques to prevent disturbance. General strength characterization by soil layer should be used for analysis of trench wall stability."

Jan 1, 2006

By Yingcai Han

The dynamic behavior of pile foundations is investigated in both theory and practice. The computation method for vibration of pile foundations and DYNAN computer program are introduced comprehensively. With a model of non-reflective boundary between the near field and far field, the Novak's method of soil-pile interaction is improved. The dynamic analysis and design of foundation for a reciprocation compressor with driver power 15,000 HP are described to illustrate the computation method of soil-pile interaction. Different design options for the piles are compared to limit the vibration of foundation and produce a safe, economic system. The design with 16 - 0.9 m piles is adopted rather than that with 25-0.5 m piles, since the larger damping is provided by the piles with larger diameter. Both field and laboratory tests were carried out to investigate the soil properties including down hole seismic tests to provide soil shear wave velocities at different depths. The method and procedure used in this study can be applied to the design of pile foundations for tall buildings, bridges and offshore platform with soil-pile interaction under seismic, blast, sea wave and other dynamic loads.

Jan 1, 2002

By P. Davies

The Hillside Smelter presently under construction at Richards Bay, Republic of South Africa, will be, on completion, the fifth largest aluminium smelter in the world. The site selected for this plant is underlain by sandy soils of variable density to depths of 30m or greater. In order to firmly establish pile founding depths required for alternative pile types in the variable subsurface conditions prevailing across the site, a pre-construction test piling programme was conducted incorporating piles instrumented with resistance strain gauges. The results allowed analysis of the relative contributions of end-bearing and shaft friction to the overall bearing capacity of each pile type and permitted comparison with the predictions of conventional static bearing capacity analyses. Conformance with acceptance criteria in respect of allowable pile head movements for single piles was also examined.

Jan 1, 1996

By Mohammad T. Izadi

Piles are, often, used for transferring load from the super structure through soft consolidating strata onto relatively stiff uncompressible soils. Downward movement of the soft soil strata develops negative skin friction and dragload around the pile shaft, with time. Traditionally the induced dragload is considered in determining the pile bearing capacity. On the other hand, field measurements on instrumented piles show that negative skin friction is reduced by the magnitude of applied live load. A method for calculating the pile bearing capacity, driven through soft consolidating strata is presented. In this method, two allowable load-bearing capacities are calculated for each pile, live load plus dead load and dead load. The proposed method, substantially, increases the allowable load bearing capacity of piles compared to calculated values by the traditional methods.

Jan 1, 2001

By Rasin Duzceer

In this paper, the results of pile load test on 24 piles from twelve sites are presented. The pile load tests were performed on 14 driven and 10 bored piles of varying diameters and lengths installed in different ground conditions in Turkey, Saudi Arabia and Kazakhstan. The purpose of this study is to evaluate and compare the axial capacity of the piles obtained using pile load test interpretation methods. Davisson, Brinch Hansen %80, Chin-Kondner, Shen-Niu, De-Beer, Housel, Mazurkiewicz, Fuller-Hoy, Brinch- Hansen (90%), Corps of Engineers, Butler Hoy and Tangent Intersection methods were used to determine the axial capacity of the piles. Static analysis using FHWA method was performed to predict the axial capacity of the piles. A statistical analysis was performed to compare and quantify the load test interpretation methods. The ratio of interpreted (Qi) to predicted (Qp) pile capacity was compared for each method. For each pile load test and for each interpretation method, the mean and coefficient of variation of (Qi)/ (Qp) were calculated. Among twelve methods investigated, the highest Qi/Qp value was obtained as 1.37 for Chin-Kondner method whereas the lowest Qi/Qp ratio of 0.70 was obtained from De Beer method.

Jan 1, 2002

By Arash Khosravifar

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

Jan 1, 2010

By 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 Ray Zelinski

Caltrans sponsored a research project in 1992 which incorporated proprietary and generic pile types. The piles were subjected to axial tensile/compressive loads in deep, soft soils. Descriptions of various pile types and systems, scenarios leading to the proposal to test the systems, and load test results were/will be provided by other presenters at this seminar. Therefore, this paper will focus on the issues surrounding use of test results and proprietary pile systems on Caltrans construction projects. The primary issues facing Caltrans during implementation are as follows: 1) producing pile cap designs for a range of pile types and loads; 2) providing construction specifications which allow fair competition among the system vendors, yet assure design and ultimate capacities; 3) Develop quality control standards for pile system materials and installation techniques which guarantee pile durability for static and dynamic loads; and 4) assure that foundations have adequate lateral capacity.

Jan 1, 1993

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 Martina Balic

Dynamic properties of the drilled shaft foundations supporting Doremus Avenue Bridge were determined by forced vibration testing. The main objectives of the substructure testing at Doremus Avenue Bridge were: (1) site evaluation with respect to the dynamic soil properties, and, (2) shaft evaluation for the purpose of definition of their dynamic stiffness. The site characterization entailed crosshole testing for the purpose of evaluation of the shear modulus profile. The drilled shaft impedance evaluation was done through forced excitation using an electromagnetic shaker. The responses of the tested shaft, as well as the response of adjacent shafts, were measured for the purpose of evaluation of the shaft interaction. To gain a better insight into the shaft dynamics, one of the shafts was instrumented with five triaxial geophones distributed along the full length of the shaft. The scope and results of the site characterization, shaft impedance and shaft interaction evaluation are presented.

Jan 1, 2004

By Maurice Guillaud

The most striking innovations on diaphragm-wall construction plant are those associated with continuous real-time trajectory monitoring of the excavating tool (either a grab or a hydro-cutter). The recent equipments are fitted with clinometers and gyrometers to control deflection, rotation or deviation from the vertical, thus allowing to install diaphragm-walls with a verticality accuracy of less than 0.3%. One of the greatest advantages of extensive use of on-board IT systems on the Hydrocutters and hydraulic grab machines is that it aids quality control by automatically producing complete real-time reports of all excavating data (verticality, depth, type of ground, rate of progress, stoppages, etc.). These reports are available to the Engineer, providing the total transparency required for Works Supervision and the Quality Assurance Plan. They also provide the Contractor with input data for databases used for optimising efficiency and progress criteria on future jobs.

Jan 1, 2002

By Matthew C. Pierson

Due to space limitations for transportation projects, many times sound walls must be constructed above mechanically stabilized earth (MSE) walls. These sound walls must resist lateral loads from wind or impact and must therefore be constructed on drilled shafts passing through the reinforced fill for the MSE Wall. Current design methods for the drilled shafts are believed to be overly conservative. Full scale lateral load testing of three foot diameter shafts contained within and solely supported by a 20 foot tall MSE block wall was conducted and the lateral capacity was evaluated. Shafts were tested individually and as a group. The data collected from full scale testing was then used to calibrate numerical models. This paper contains a discussion of how the facing type and stiffness affects the behavior of the numerical model as well as selected comparisons between the actual test data and selected model simulation results.

Jan 1, 2009