Geotechnical Laboratory Measurements for Engineers

Geotechnical Laboratory Measurements for Engineers John T. Germaine and Amy V. Germaine Copyright © 2009 by John Wiley & Sons, Inc.

Geotechnical Laboratory Measurements for Engineers

John T. Germaine and Amy V. Germaine

John Wiley & Sons, Inc.

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Copyright © 2009 by John Wiley & Sons, Inc. All rights reserved

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Library of Congress Cataloging-in-Publication Data:

ISBN: 978-0-470-15093-1Germaine, John T. Geotechnical laboratory measurements for engineers / John T. Germaine and Amy V. Germaine. p. cm. Includes index. ISBN 978-0-470-15093-1 (paper/website) 1. Soil dynamics. 2. Soils—Testing. 3. Soils—Composition. 4. Soils—Density—Measurement. I. Germaine, Amy V. II. Title. TA711.G48 2009 624.1'510287—dc22

2009007439

Printed in the United States of America

10 9 8 7 6 5 4 3 2 1

Contents

P R E FA C E X I

A C K N O W L E D G E M E N T S X I I I

P A R T I

Chapter 1 Background Information for Part I 3Scope, 3Laboratory Safety, 4Terminology, 5Standardization, 6Evaluation of Test Methods, 8Precision and Bias Statements, 9Laboratory Accreditation, 11Profi ciency Testing, 12Technician Certifi cation, 12Unit Convention, 12Signifi cant Digits, 13Test Specifi cation, 14Sampling, 15Processing Bulk Material, 17Test Documentation, 19Spreadsheets, 20Reporting Test Results, 20Typical Values, 21Further Reading and Other References, 21References, 22

Chapter 2 Phase Relationships 24Scope and Summary, 24Typical Materials, 25Background, 25

Contents v

vi Contents

Typical Values, 33Calibration, 33Specimen Preparation, 35Procedure, 35Precision, 37Detecting Problems with Results, 38Reference Procedures, 38References, 38

Chapter 3 Specifi c Gravity 39Scope and Summary, 39Typical Materials, 39Background, 39Typical Values, 44Calibration, 45Specimen Preparation, 45Procedure, 45Precision, 50Detecting Problems with Results, 51Reference Procedures, 51References, 51

Chapter 4 Maximum Density, Minimum Density 52Scope and Summary, 52Typical Materials, 52Background, 52Typical Values, 55Calibration, 55Specimen Preparation, 57Procedure, 57Precision, 58Detecting Problems with Results, 58Reference Procedures, 59References, 59

Chapter 5 Calcite Equivalent 60Scope and Summary, 60Typical Materials, 60Background, 60Typical Values, 62Calibration, 63Specimen Preparation, 65Procedure, 65Precision, 66Detecting Problems with Results, 66Reference Procedures, 66References, 66

Chapter 6 pH and Salinity 68Scope and Summary, 68Typical Materials, 68Background, 68Typical Values, 74Calibration, 75Specimen Preparation, 76Procedure, 76

Contents vii

Precision, 78Detecting Problems with Results, 78Reference Procedures, 79References, 79

Chapter 7 Organic Content 80Scope and Summary, 80Typical Materials, 80Background, 80Typical Values, 82Calibration, 82Specimen Preparation, 82Procedure, 82Precision, 83Detecting Problems with Results, 83Reference Procedures, 83References, 83

Chapter 8 Grain Size Analysis 84Scope and Summary, 84Typical Materials, 84Background, 84Typical Values, 107Calibration, 109Specimen Preparation, 111Procedure, 112Precision, 115Detecting Problems with Results, 116Reference Procedures, 116References, 116

Chapter 9 Atterberg Limits 117Scope and Summary, 117Typical Materials, 117Background, 117Typical Values, 130Calibration, 132Specimen Preparation, 134Procedure, 135Precision, 137Detecting Problems with Results, 138Reference Procedures, 138References, 138

Chapter 10 Soil Classifi cation and Description 140Scope and Summary, 140Typical Materials, 140Background, 141Calibration, 156Specimen Preparation, 157Procedure, 157Precision, 160Detecting Problems with Results, 160Reference Procedures, 160References, 160

viii Contents

P A R T I I

Chapter 11 Background Information for Part II 163Scope and Summary, 163Intact Sampling, 164Processing Intact Samples, 169Reconstituting Samples, 184Transducers, 189Data Collection and Processing, 203References, 209

Chapter 12 Compaction Test Using Standard Effort 210Scope and Summary, 210Typical Materials, 210Background, 211Typical Values, 219Calibration, 220Specimen Preparation, 220Procedure, 220Precision, 221Detecting Problems with Results, 222Reference Procedures, 222References, 222

Chapter 13 Hydraulic Conductivity: Cohesionless Materials 223Scope and Summary, 223Typical Materials, 223Background, 223Typical Values, 233Calibration, 234Specimen Preparation, 235Procedure, 235Precision, 237Detecting Problems with Results, 238Reference Procedures, 238References, 238

Chapter 14 Direct Shear 239Scope and Summary, 239Typical Materials, 239Background, 240Typical Values, 248Calibration, 248Specimen Preparation, 250Procedure, 251Precision, 254Detecting Problems with Results, 254Reference Procedures, 255References, 255

Chapter 15 Strength Index of Cohesive Materials 256Scope and Summary, 256Typical Materials, 256Background, 256Typical Values, 264

Contents ix

Calibration, 264Specimen Preparation, 266Procedure, 267Precision, 272Detecting Problems with Results, 272Reference Procedures, 273References, 273

Chapter 16 Unconsolidated-Undrained Triaxial Compression 275Scope and Summary, 275Typical Materials, 276Background, 276Typical Values, 286Calibration, 286Specimen Preparation, 289Procedure, 289Precision, 292Detecting Problems with Results, 292Reference Procedures, 293References, 293

Chapter 17 Incremental Consolidation By Oedometer 294Scope and Summary, 294Typical Materials, 294Background, 294Typical Values, 324Calibration, 324Specimen Preparation, 325Procedure, 326Precision, 331Detecting Problems with Results, 331Reference Procedures, 332References, 332

A P P E N D I C E S

Appendix A Constants And Unit Conversions 334

Appendix B Physical Properties Of Pure Water 338

Appendix C Calculation Adjustments For Salt 340

I N D E X 345

Preface

This textbook is divided into two parts, according to a general division of test result characteristics and level of background knowledge necessary to perform the tests. Part I focuses on relatively simple tests that are used to characterize the nature of soils and can be performed on bulk materials. Part II increases the level of testing complexity, places more emphasis on engineering properties, and requires a larger investment in laboratory equipment. These topics may be covered in an under-graduate civil or geotechnical engineering laboratory course.

An ancillary web site has been created for this textbook. The web site ( www.wiley.com/college/germaine ) is divided by chapter and includes data sheets, spreadsheets, and example data sets. In addition, there are online resources for instructors that provide template data sheets with embedded data reduction formulas.

There are a large number of tests that are performed on geo - materials. This book is not intended to be all inclusive, but rather covers a selection of the most common and essential tests, while maintaining a broad cross - section of methods and devices. In general, testing of geo - materials is a slow process according to “ clock time. ” This is mostly due to the need for pore water to come to equilibrium. Cost - effective, high - quality testing is possible by understanding the important factors and working with nature to use labor wisely. A goal of this text is to provide guidance for effi cient testing without sacrifi c-ing the quality of results. Effi ciency can be achieved by tailoring techniques to individual circumstances and understanding when shortcuts are feasible.

The background chapter to each of the two parts provides general information that applies to the chapters that follow. Test - specifi c information is included in the pertinent chapter. Each testing chapter provides background information to understand the concepts and objectives of the method, a discussion of important factors useful for professional practice, a list of the minimum equipment requirements, detailed procedures and guidance for performing the test, and the calculations required to produce the results. The procedures are provided for specifi c situations and would be most useful for instruc-tional purposes. These instructions could be modifi ed for commercial application to increase productivity and effi ciency.

The text is set up to allow instructors to choose which laboratories to include in their courses. The knowledge gained through individual tests tends to be cumulative as the text progresses. However, it is not intended that all of the laboratories would be taught, one after the other, as part of a single course.

Although this book is well suited to teaching a geotechnical laboratory course, the practicing geotechnical engineer should fi nd this text useful as a reference on the important details relative to testing. This is especially important when design-ing sophisticated subsurface characterization and corresponding advanced laboratory testing programs. The information presented is essential to the geotechnical engineer. The text helps develop a working knowledge of laboratory capabilities and testing methods. Laboratory testing is also a large part of geotechnical research. Perhaps the most valuable experience is that the knowledge gained by performing the laboratories reinforces the understanding of soil behavior.

It is hoped that the practicing engineer will understand the following motto: Only perform the tests you need. But if you need to do it, do it correctly.

Preface xi

Acknowledgements

Several individuals in the geotechnical fi eld have had tremendous impacts on the authors, both professionally and as family friends.

Stephen Rudolph is the machinist and designer responsible for the equipment modifi cations necessary to accomplish the experiments that appear in many chapters of this work. His dedication and skills are admired and appreciated.

Charles Ladd has been a mentor and colleague to both of us since we entered MIT as students. His guidance in understanding soil behavior is treasured.

Richard Ladd has been a valued colleague and mentor to both of us through the years. Richard is always available and ready to discuss the fi ner points of testing, and his feedback is valued dearly.

Several consulting clients deserve recognition for providing interesting work and for probing into the details relative to geotechnical testing. Two of those individuals are Demetrious Koutsoftas and Richard Reynolds. We can never thank them enough.

Jack ’ s students of the past, present, and future are to be commended for asking questions and pushing the boundaries of geotechnical testing. They keep the job of teaching fresh, challenging, and interesting.

Finally, we wish to thank Bill DeGroff and Fugro Consultants, Inc., for affording Amy the fl exible schedule that allowed for the writing of this textbook.

Acknowledgements xiii