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Determination of Soil Properties for Sandy Soils and Road Base

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Determination of Soil Properties for Sandy Soils and Road Base DETERMINATION OF SOIL PROPERTIES FOR SANDY SOILS AND ROAD BASE AT RIVERSIDE CAMPUS USING LABORATORY TESTING AND NUMERICAL SIMULATION A Thesis by DEEYVID OSCAR SAEZ BARRIOS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE May 2010 Major Subject: Civil Engineering DETERMINATION OF SOIL PROPERTIES FOR SANDY SOILS AND ROAD BASE AT RIVERSIDE CAMPUS USING LABORATORY TESTING AND NUMERICAL SIMULATION A Thesis by DEEYVID OSCAR SAEZ BARRIOS Submitted to the Office of Graduate Studies of Texas A&M University in partial fulfillment of the requirements for the degree of MASTER OF SCIENCE Approved by: Chair of Committee, Jean-Louis Briaud Committee Members, Charles Aubeny Julian Kang Head of Department, John Niedzwecki Major Subject: Civil Engineering iii ABSTRACT Determination of Soil Properties of Sandy Soils and Road Base at Riverside Campus Using Laboratory Testing and Numerical Simulation. (May 2010) Deeyvid Oscar Saez Barrios, B.En., Technological University of Panama Chair of Advisory Committee: Jean-Louis Briaud This study evaluated the soil properties of clean sand, a silty sand, and a road base that are extensively used as a backfill for full-scale testing at Riverside Campus at Texas A&M University. The three soils were collected at the Riverside Campus and the testing schedule included grain size analysis, hydrometer test, specific gravity, maximum dry density, Atterberg limit, stiffness, direct shear test, triaxial test, and a simple procedure to estimate the maximum and minimum void ratio of the clean sand. Relation between strength/deformation, vertical displacement/shear displacement, and physical properties were evaluated to estimate the frictional resistance and angle of dilation of the clean sand and the silty sand. Numerical simulations of the Direct Shear Test (DST) were conducted on the clean sand using Finite Element Model in the computer program LS-DYNA. The simulations were intended to reproduce the Direct Shear Test (DST) to estimate the frictional resistance and dilatancy effects of the clean sand under different compressive stresses. iv Field tests were also conducted on the clean sand and the road base. These tests included the in-situ density determination, in-situ water content, and the soil modulus using the Briaud Compaction Device (BCD). v DEDICATION To my parents: Eyda Raquel Barrios Rivera and Oscar Alberto Saez Barrios, My sister; Yessica Lisbeth Saez Barrios, And my girlfriend: Librada Maria Velazquez Mudarra vi ACKNOWLEDGEMENTS I would first like to thank you, Dr. Jean- Louis Briaud, for supporting, advising and guiding me on this project and on my graduate school career. I would also like to thank Dr. Charles Aubeny for aiding in my understanding of frictional resistance of sands. I am indebted to Mr. Mike Linger for his assistance and technical support in all my laboratory endeavors. I also acknowledge the help of Mr. Gustavus Lee, Mr. Gary Gerke, Seok-Gyo Lim, Hrishikesh Sharma, and Michelle Lee Bernhardt for their assistance in collecting samples, laboratory testing and Numerical Simulation. My sincere gratitude goes out to my entire family, and specifically to my parents, who encouraged me to go to college and then on to graduate school. I would like to thank all my friends in the geotechnical group for their support and enjoyment in work and life. vii TABLE OF CONTENTS Page ABSTRACT .............................................................................................................. iii DEDICATION .......................................................................................................... v ACKNOWLEDGEMENTS ...................................................................................... vi TABLE OF CONTENTS .......................................................................................... vii LIST OF FIGURES ................................................................................................... x LIST OF TABLES .................................................................................................... xviii 1. INTRODUCTION ............................................................................................. 1 1.1 General Concepts ..................................................................................... 1 1.2 Finding ..................................................................................................... 3 2. EXECUTIVE SUMMARY ............................................................................... 5 3. BACKGROUND ............................................................................................... 8 3.1 Shear Strength of Granular Soils .............................................................. 8 3.2 Mechanism Contributing to Shear Strength of Granular Soils ................ 8 3.3 Particle Shape ........................................................................................... 9 3.4 Particle Size and Gradation ...................................................................... 9 3.5 Effect of Confining Pressure on the Shear Strength ................................ 10 3.6 Soil Modulus of Granular Materials ......................................................... 12 3.7 Frictional Resistance, Critical State, and Dilatancy Effect of Sands ....... 13 3.7.1 Angle of Internal Friction ................................................................ 13 3.7.2 The Critical State Concept .............................................................. 14 3.7.3 The Dilatancy Effect of Granular Materials .................................... 15 4. TEST PROCEDURES ....................................................................................... 22 4.1 Density and Water Content ...................................................................... 22 4.1.1Summary of the Test Procedure for the Sand Cone Method ............ 23 4.2 Grain Size Analysis .................................................................................. 26 4.3 Hydrometer Analysis ................................................................................ 27 viii Page 4.4 Atterberg Limits ....................................................................................... 31 4.5 Specific Gravity (Gs) ............................................................................... 33 4.6 Estimation of the Minimum and Maximum Void Ratio .......................... 35 4.7 Direct Shear Test (DST) ........................................................................... 37 4.7.1 Area Correction of the Soil Specimen ............................................. 41 4.7.2 Checking the Frictional Resistance of the Direct Shear Apparatus (DSA) ............................................................................. 41 4.8 Triaxial Compression Test (TC) .............................................................. 43 4.9 Soil Modulus Test (Briaud Compaction Device, BCD). .......................... 44 4.10 Modified Proctor Compaction Test ........................................................ 47 5. TESTS RESULTS FOR THE CLEAN SAND................................................. 50 5.1 Field Test Results for the Clean Sand (Density, Soil Modulus, and Water Content .......................................................................................... 51 5.2 Index Properties ........................................................................................ 53 5.3 Estimation of the Minimum and Maximum Void Ratio .......................... 57 5.4 Modified Proctor Compaction and Soil Modulus Curve ......................... 59 5.5 Comparison between the Dry Unit Weight and the Laboratory Soil Modulus ............................................................................................ 62 5.6 Angle of Repose ...................................................................................... 63 5.7 Direct Shear Test (DST) ........................................................................... 65 5.8 Estimation of the Dilation Angle of the Clean Sand from the DST ......... 71 5.9 Triaxial Compression Test (TC) .............................................................. 79 6. TESTS RESULTS FOR THE SILTY SAND.................................................... 81 6.1 Index Properties ......................................................................................... 81 6.2 Direct Shear Test (DST) ............................................................................ 85 6.3 Estimation of the Angle of Dilation for the Silty Sand ............................. 92 7. TESTS RESULTS FOR THE ROAD BASE .................................................... 94 7.1 Field Tests Results for the Road Base (Density, Soil Modulus, and Water Content) .......................................................................................... 94 7.2 Index Properties ......................................................................................... 95 7.3 Modified Proctor Compaction Test ........................................................... 101 ix Page 7.4 Comparison between the Dry Unit Weight of the Soil and the Soil Modulus ............................................................................................ 101 7.5 Triaxial Compression Test (TC) .............................................................. 105 8. PROPOSED TEST FOR THE CRUSHED ROCK .......................................... 108 8.1 Proposal for Full-Scale Direct Shear Test for Large Aggregates ............
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