Analysis of the Effects of Heavily Loaded Mat Foundation on Adjacent Drilled Shaft Foundation

Analysis of the Effects of Heavily Loaded Mat Foundation on Adjacent Drilled Shaft Foundation
Author: Pravin Jha
Publisher:
Total Pages: 224
Release: 2015
Genre: Environmental geotechnology
ISBN:

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Construction of heavily loaded shallow foundations adjacent to deep foundation is generally avoided in common geotechnical engineering practice to minimize additional loads on deep foundations. However, with the growing trend of urbanization leading to a demand of new construction, it is not always possible to avoid such situation where a heavily loaded shallow foundation will be right next to the infrastructure resting on deep foundations. When this situation cannot be avoided, influence of soil pressures and deformations in soil, created by shallow foundation on adjacent deep foundation, must be evaluated. The study of interaction between deep foundations has been carried out by several researchers in terms of pile-soil-pile interaction. Similarly, there are many published studies on interaction between closely spaced shallow foundations in terms of bearing capacity and settlement. However, not much published literature is available for practicing engineers to analyze and design deep and shallow foundations when they are constructed adjacent to each other. Construction of heavily loaded mat adjacent to drilled shafts would cause complex interaction between the foundations. However, lateral stress and drag forces on the shafts resulting from the heavy load on the mat foundation are the two major factors that would affect the design and performance of shafts. Since there is not much literature and guidance available to analyze and design such kind of situation, a preliminary investigation was first carried out where magnitude of the drag forces and lateral forces on drilled shafts were estimated using simple geotechnical engineering principles. The limitations of preliminary analysis led to the need of more sophisticated analysis using finite element techniques. As a part of this research, a detailed parametric study using finite element techniques has been performed to better understand stress and deformation distributions, and develop simplified methods to analyze this type of problems. A stress bulb for lateral stresses under a uniformly loaded square foundation, similar to the pressure bulb for vertical stresses which is widely used in the geotechnical engineering practice, has been proposed, which provides a significant tool for practicing engineers to understand lateral stress distribution below a uniformly loaded square area and estimate lateral stresses on nearby deep foundations. Similarly, a deformation bulb under a uniformly loaded square foundation is proposed. A new term “Isodefers” has been proposed to refer the lines of equal deformation. Isodefers are also a significant tool for practicing engineers to understand vertical deformation distribution below a uniformly loaded square area and estimate drag forces on nearby deep foundations. A case study emerging from similar real life scenario has also been analyzed and results are discussed with suitable recommendations.

Drilled Shafts

Drilled Shafts
Author: Michael W. O'Neill
Publisher:
Total Pages:
Release: 1999
Genre: Foundations
ISBN:

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Drilled Shaft Foundations for Noise Barrier Walls and Slope Stabilization

Drilled Shaft Foundations for Noise Barrier Walls and Slope Stabilization
Author: Robert Y. Liang
Publisher:
Total Pages: 260
Release: 2002
Genre: Noise barriers
ISBN:

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The objectives of this research are to develop a methodology that would allow the use of the SPT (Standard Penetration Test) results for analysis and design of the laterally loaded drilled shafts and to develop a methodology for designing the drilled shafts to stabilize the unstable slopes and embankments.

Tall Building Foundation Design

Tall Building Foundation Design
Author: Harry G. Poulos
Publisher: CRC Press
Total Pages: 761
Release: 2017-07-20
Genre: Technology & Engineering
ISBN: 1351652141

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This book provides a comprehensive guide to the design of foundations for tall buildings. After a general review of the characteristics of tall buildings, various foundation options are discussed followed by the general principles of foundation design as applied to tall buildings. Considerable attention is paid to the methods of assessment of the geotechnical design parameters, as this is a critical component of the design process. A detailed treatment is then given to foundation design for various conditions, including ultimate stability, serviceability, ground movements, dynamic loadings and seismic loadings. Basement wall design is also addressed. The last part of the book deals with pile load testing and foundation performance measurement, and finally, the description of a number of case histories. A feature of the book is the emphasis it places on the various stages of foundation design: preliminary, detailed and final, and the presentation of a number of relevant methods of design associated with each stage.

Basics of Foundation Design

Basics of Foundation Design
Author: Bengt Fellenius
Publisher: Lulu.com
Total Pages: 488
Release: 2017-03-17
Genre: Technology & Engineering
ISBN: 1365824004

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The "Red Book" presents a background to conventional foundation analysis and design. The text is not intended to replace the much more comprehensive 'standard' textbooks, but rather to support and augment these in a few important areas, supplying methods applicable to practical cases handled daily by practising engineers and providing the basic soil mechanics background to those methods. It concentrates on the static design for stationary foundation conditions. Although the topic is far from exhaustively treated, it does intend to present most of the basic material needed for a practising engineer involved in routine geotechnical design, as well as provide the tools for an engineering student to approach and solve common geotechnical design problems.

Settlement Analysis of Drilled Shaft Foundation on Natural and Lime-treated Compressible Clayey Soil

Settlement Analysis of Drilled Shaft Foundation on Natural and Lime-treated Compressible Clayey Soil
Author: Abdusemed Kemal Ali
Publisher:
Total Pages: 72
Release: 2015
Genre:
ISBN:

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Drilled shaft foundations are primarily used to support structures such as bridge piers, buildings, and transmission towers. The main advantage of a drilled shaft foundation is that it transfers loads to the stronger subsoil layers or rock strata lying underneath, giving maximum bearing capacity to the overlying structure. This goal of this research is to load bearing capacity of a drilled shaft on both treated and untreated compressible soil. In this study, both analytical and numerical studies were conducted to investigate the effect of lime treatment on the settlement of the drilled shaft. Extensive literature study was conducted on analysis of axially-loaded drill shafts and novel chemical ground improvement techniques for compressible clay. Basic laboratory tests were conducted, and engineering properties of both natural and lime treated soils were determined. The varying depth-settlement response of a vertically loaded drill shaft was analyzed, on both treated and non-treated clay soils. Numerical analysis was performed, using PLAXIS 2D and the soil parameters obtained from laboratory tests. The main purpose of using the lime slurry pressure injection method is to reduce the project expenses by improving the capacity of the soil, as well as to increase the load bearing capacity of the foundations where bedrock is very deep. During this study, three case scenarios were considered, involving varying depths of the drilled shaft, diameter of the drilled shaft, and the depth of the treated soil. The maximum settlement curves obtained analytically from the studies for the natural and treated soils were compared with the curves from the numerical results. Finally, recommendations and advantages of using lime treatment on compressible clays are highlighted.