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This book presents a one-stop reference to the empirical correlations used extensively in geotechnical engineering. Empirical correlations play a key role in geotechnical engineering designs and analysis. Laboratory and in situ testing of soils can add significant cost to a civil engineering project. By using appropriate empirical correlations, it is possible to derive many design parameters, thus limiting our reliance on these soil tests. The authors have decades of experience in geotechnical engineering, as professional engineers or researchers. The objective of this book is to present a critical evaluation of a wide range of empirical correlations reported in the literature, along with typical values of soil parameters, in the light of their experience and knowledge. This book will be a one-stop-shop for the practising professionals, geotechnical researchers and academics looking for specific correlations for estimating certain geotechnical parameters. The empirical correlations in the forms of equations and charts and typical values are collated from extensive literature review, and from the authors' database.



Chapter 1. Introduction

This chapter is an introduction to the book. It discusses laboratory and in situ tests, their advantages and limitations. The chapter introduces the test covered by the book and discusses the necessity of empirical relationships for the practising engineer. Finally, it briefly mentions how the book is organised into the nine different chapters.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 2. Geotechnical Properties of Soils – Fundamentals

This chapter gives a brief overview of the geotechnical properties commonly determined in the laboratory, their relevance in soil mechanics and laboratory tests for determining them. The properties discussed include Atterberg limits, the different densities, particle size distribution, permeability, and the parameters related to consolidation and shear strength. The tests required to obtain these parameters are also discussed. The information in this chapter gives the necessary background to understand the empirical correlations relating the different parameters determined in the laboratory.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 3. Correlations for Laboratory Test Parameters

With the necessary theoretical framework covered in Chapter 2, this chapter discusses the correlations relating the different soil parameters determined in the laboratory for both cohesive and cohesionless soils. Parameters covered in this chapter include permeability, consolidation, undrained and drained shear strength, stiffness and modulus and coefficient of earth pressure at rest. The relationships between the parameters discussed herein are not necessarily all empirical. Some theoretical relationships are also given. In addition to the theoretical and empirical relationships, typical values of the parameters are provided wherever possible. Correlations with laboratory data to be directly used in pile design are also provided.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 4. Standard Penetration Test

This chapter provides a detailed description of the Standard Penetration Test (SPT) procedure and corrections to be applied to the SPT N value and hammer energy. Correlations of SPT N value with relative density, peak drained friction angle and modulus of elasticity of sand are discussed in detail. In clays, correlations to obtain the undrained shear strength, preconsolidation pressure, over consolidation ratio are provided. As the SPT N value is used extensively in the design of foundations, correlations to obtain foundation bearing capacity for both shallow and deep foundations are provided.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 5. Cone Penetrometer Test

This chapter covers one of the most popular insitu tests, the cone penetrometer test (CPT). A brief description of different types of tests has been provided. The piezocone test, an advanced CPT, is described including the test procedure and the parameters obtained in the field. Pore pressure transducer placement locations and the corrections to measured pore pressures are presented. A detailed discussion of soil classification using cone test results is provided. Correlations for design parameters related to sands and clays are discussed separately. For sands, correlations include relative density, friction angle, modulus and small strain modulus. For clays, correlations include the undrained shear strength, over consolidation ratio, constrained modulus, small strain shear modulus, compressibility, friction angle, unit weight and permeability. As the CPT test competes with SPT test for popularity, correlations between the two tests are also discussed. Correlations to use CPT derived parameters directly to calculate the ultimate bearing capacity of shallw and deep foundations are presented. The chapter concludes with a section on liquefaction assessment using CPT as well as SPT results.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 6. Pressuremeter Test

This chapter focusses on another insitu test, the pressuremeter. The Menard type pressuremeter and the self boring pressuremeter are described including the test procedures and stress relaxation at the commencement of the test. The pressuremeter test has a strong theoretical base and this is described in the book. A description of obtaining the insitu lateral stress, modulus, undrained shear strength for cohesive soils and the friction angle for granular soils from theory is provided. Empirical correlations to correct the parameters obtained from a direct theoretical interpretation of the pressuremeter test curve are provided. The use of Menard type pressuremeter test results directly in the design of shallow foundations using empirical correlations is described. Correlations to obtain the ultimate bearing capacity and ultimate skin friction of deep foundations are also presented. Finally, correlations between the pressuremeter test results and SPT as well as the cone penetrometer test results are provided.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 7. Dilatometer Test

Dilatometer is one of the latest arrivals among the in situ testing devices. It has become more versatile with the development of seismic dilatometer, which also measures the shear wave velocity. The three major indices computed in the dilatometer test are the material index ID, horizontal stress index KD, and dilatometer modulus ED. These three are used in identifying the soil type and determining the soil parameters and this chapter provides correlations to obtain these parameters.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 8. Vane Shear Test

It describes the vane shear test which is one of the most widely used in situ tests to assess the undrained shear strength of saturated cohesive soils. The test equipment and procedure to carry out the test are described in detail as well as interpretation of the data, and how the results could be used in geotechnical design. Empirical correlations are provided to correct the measured field vane shear strength values and the shortcomings in these methods are highlighted.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das

Chapter 9. Laboratory Rock Tests

The rock mass is made of intact rock and one or more sets of discontinuities. The intact rock specimens that are recovered from coring represent a relatively small volume of the rock mass and do not fully reflect the presence of discontinuities. The behaviour of the rock mass is governed mostly by the discontinuities than the properties of the intact rocks. Uniaxial compressive strength, Brazilian indirect tensile strength and the point load strength are some of the properties that reflect the strength of the intact rock. Typical values of these parameters and the interrelationships among them are discussed in this chapter.

Jay Ameratunga, Nagaratnam Sivakugan, Braja M. Das


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