Measuring Residual Strength of Liquefied Soil with the Ring Shear Device
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University of New Hampshire University of New Hampshire Scholars' Repository Master's Theses and Capstones Student Scholarship Spring 2011 Measuring residual strength of liquefied soil with the ring shear device Jay Hargy University of New Hampshire, Durham Follow this and additional works at: https://scholars.unh.edu/thesis Recommended Citation Hargy, Jay, "Measuring residual strength of liquefied soil with the ring shear device" (2011). Master's Theses and Capstones. 828. https://scholars.unh.edu/thesis/828 This Thesis is brought to you for free and open access by the Student Scholarship at University of New Hampshire Scholars' Repository. It has been accepted for inclusion in Master's Theses and Capstones by an authorized administrator of University of New Hampshire Scholars' Repository. For more information, please contact [email protected]. MEASURING RESIDUAL STRENGTH OF LIQUEFIED SOIL WITH THE RING SHEAR DEVICE BY JAY HARGY BS Geology (Engineering Emphasis) Northern Arizona University, 1996 THESIS Submitted to the University of New Hampshire in Partial Fulfillment of the Requirements for the Degree of Master of Science in Civil Engineering May, 2011 UMI Number: 1498960 All rights reserved INFORMATION TO ALL USERS The quality of this reproduction is dependent upon the quality of the copy submitted. In the unlikely event that the author did not send a complete manuscript and there are missing pages, these will be noted. Also, if material had to be removed, a note will indicate the deletion. UMT Dissertation Publishing UMI 1498960 Copyright 2011 by ProQuest LLC. All rights reserved. This edition of the work is protected against unauthorized copying under Title 17, United States Code. ProQuest LLC 789 East Eisenhower Parkway P.O. Box 1346 Ann Arbor, Ml 48106-1346 This thesis has been examined and approved. (deceased) Thesis Director, Pedro de Alba Professor of Civil Engineering, UNH Mandar Dewoolkar Associate Professor of Civil Engineering, UVM Jean Benoit Professor of Civil Engineering, UNH X 'T^U^ JeffiMy S. Melton Research Assistant Professor of Civil Engineering, UNH s>f/3 / ao// Date DEDICATION This thesis is dedicated to my advisor, the late Pedro de Alba (1939-2011). It has always been my intention to dedicate my work to him, but with his recent passing this dedication takes on even more meaning. During my two-plus years of knowing Dr. de Alba, I have gained the utmost respect for him. I knew I was working with a great man after seeing his name referenced in many of the textbooks used during my coursework. It was only recently that I realized that he studied at UC-Berkeley under Dr. H. Bolton Seed, the founder of geotechnical earthquake engineering. Dr. Seed's success is due in part to Pedro's hard work. During his 33 years at UNH, Dr. de Alba continued on to make many more major contributions to geotechnical earthquake engineering and the liquefaction resistance of sands. He was a mentor and a role model to numerous students and colleagues who have become successful engineers in their own right. Dr. de Alba was also an outstanding gentleman who showed great compassion in his work, and for his students; always asking about my family before we spoke of school work. His hard work and dedication to his profession and students were exemplary, and I am truly honored to have been guided by him. He is missed. iii ACKNOWLEDGMENTS This work was funded in part by the U.S. National Science Foundation (NSF) (award number CMMI-0724080), and was part of a larger project directed by Dr. Mandar Dewoolkar from the University of Vermont. He and his student Ian Anderson greatly contributed to the NSF report used as a starting point for this document. Mr. Robb Wallen and Dr. John McCartney of the University of Colorado were valuable help in centrifuge testing and must be acknowledged. Ian, Robb, and I spent many long days in the lab and nowhere near enough time enjoying the many amenities of Boulder. Besides the thesis work, my success at UNH would not have been possible without the help from Dr. Jean Benoit. I thank him and Dr. Pedro de Alba for their direction and guidance, patience with my misuse of words, and general concern for my well-being and success. Dr. Jeffery Melton is thanked for stepping in as advisor on short notice. I thank Drs. Ray Cook, Jo Daniel, and David Gress for providing TA positions during my stent at UNH. Shawn Wads worth, UNH Civil Engineering Technician, must also be mentioned. He is the go-to guy for help with anything lab related. Also, Steve Jackson from Axis New England, and Rob Cinq-Mars and Bob Champlin from UNH helped with programming and machine modifications. Last, but by far not least, I acknowledge my chief editor, wife, and best friend, Sandy Hargy. I thank her for allowing me to ignore her, and our daughter Ruby, as I spent too much time with my books. We shared the same roof, but I have missed the past two years with them. Their love and support through it all have been invaluable. iv TABLE OF CONTENTS DEDICATION iii ACKNOWLEDGEMENTS iv TABLE OF CONTENTS v LIST OF TABLES vii LIST OF FIGURES viii ABSTRACT ix CHAPTER PAGE 1. INTRODUCTION 1 Project Background 1 Causes and Effects of Liquefaction 2 Earthquakes 3 Collapse Theory 4 Static Liquefaction 6 Structural Failure of Volcanoes 8 Selection of Residual Strength Values 9 Back-Calculation Based on Failure Case Histories 9 Standard Laboratory Testing 11 Project Goal and Components 13 2. THE RING SHEAR DEVICE 16 Testing Machine 16 Sample Chamber 16 Top Ring 18 O-Rings 20 Drive Motor and Controller 23 Data Collection System 27 Rainer 27 Other Key Components 28 Machine Calibration 29 Machine Maintenance and Modifications 30 Sample Chamber, Top Ring, and O-rings 31 Rainer Construction 32 Other Modifications 33 v 3. MATERIALS TESTED 35 Sand 35 Index Properties 35 Shear Strength Properties 40 F-75 Specimen Preparation Methods 44 Pore Fluid 48 4. RING SHEAR TESTING 49 Machine Preparation 49 Constructing a Specimen 52 Sand Deposition 52 Saturation Process 53 Specimen Uniformity 55 Testing Procedure 55 Post Testing Procedures 58 Data Reduction 59 Special Tests 63 Shear Zone Determination 63 Lower Initial Vertical Stress 65 Pore Pressure Dissipation Tests 66 Testing with Holliston 00 Sand 67 5. COMPARISON TESTING 69 Centrifuge Tests 69 Centrifuge Model Setup 69 Centrifuge Specimen Preparation 72 Centrifuge Testing Procedures 73 Centrifuge Test Results 73 Modified Triaxial Tests 83 Modified Triaxial System Description 83 Modified Triaxial Specimen Preparation 84 Modified Triaxial Test Results 85 6. RING SHEAR RESULTS AND COMPARISONS 89 Ring Shear Results 89 Comparison of Test Results 92 Comparison with Back-Calculated Field Values 94 Comparison with Previous Ring Shear Results 100 7. CONCLUSIONS AND RECOMMENDATIONS 103 Conclusions 103 Recommendations 105 8. REFERENCES 108 APPENDIX A-MACHINE CALIBRATION RESULTS 115 APPENDIX B - F-75 SAND MATERIAL PROPERTY TESTING DATA 125 APPENDIX C-RESIDUAL STRENGTH TESTING DATA 130 VI LIST OF TABLES Table 3.1. Summary of F-75 sand index properties 36 Table 5.1. Centrifuge testing conditions and rough coupon results 74 Table 5.2. Modified triaxial testing conditions and results 88 Table 6.1. Ring shear testing conditions and results 91 vii LIST OF FIGURES Figure 1.1. Las Colinas Flowslide, El Salvador, (after Evans and Bent, 2004) 3 Figure 1.2. Coal-mine waste flowslide, British Columbia, (after Hungr et al., 2002) 5 Figure 2.1. A schematic of UNH ring shear device 17 Figure 2.2. Sample chamber, torque load cell, and pneumatic bladder 18 Figure 2.3. Top ring 20 Figure 2.4. Motion Planner cyclic motion code PROG23 25 Figure 2.5. Motion Planner monotonic motion code PROG24 26 Figure 2.6. Rainer and leveling gage 28 Figure 3.1. Grain-size distribution curves of F-75 sand 37 Figure 3.2. Summary of F-75 sand friction angle data 41 Figure 4.1. Ring shear testing sheet 50 Figure 4.2. Typical processed data from a ring shear test 57 Figure 4.3. Raw torque load cell data plot 60 Figure 4.4. Typical spread of residual strength values (Test 106) 62 Figure 4.5. Shear band on RS test specimen 64 Figure 4.6. Material strength gain with pore pressure loss, RS specimens 67 Figure 5.1. Typical centrifuge model configuration 70 Figure 5.2. Photograph of a centrifuge model installed on the swing platform 71 Figure 5.3. Typical data plot of rough coupon pulling force 76 Figure 5.4. Centrifuge tests results 78 Figure 5.5. Centrifuge rough coupon data residual strength ratio plot 78 Figure 5.6. Coupon force vs. effective stress (drive motor measurements) 80 Figure 5.7. Coupon force vs. effective stress (slip-ring measurements) 80 Figure 5.8. Coupon shear band 83 Figure 5.9. Modified triaxial system schematic (not to scale) 84 Figure 5.10. Typical modified triaxial test result 86 Figure 5.11. Modified triaxial test results 87 Figure 5.12. Modified triaxial residual strength ratio plot 87 Figure 6.1. Ring shear tests results 90 Figure 6.2. Ring shear data residual strength ratio plot 90 Figure 6.3. Exponential trends in testing results 93 Figure 6.4. Residual strength ratio comparisons 93 Figure 6.5. Comparison of back-calculated Sur with range of F-75 test result trends 95 Figure 6.6. Back-calculated residual strength ratios with F-75 test result trends 95 Figure 6.7. CPT based residual strength ratio comparisons 98 Figure 6.8. Previous ring shear results, Holliston 00 sand 101 Figure 6.9. Current ring shear results, F-75 sand 101 vin ABSTRACT MEASURING RESIDUAL STRENGTH OF LIQUEFIED SOIL WITH THE RING SHEAR DEVICE by Jay Hargy University of New Hampshire, May, 2011 Natural and constructed slopes may contain zones of loose granular soils capable of liquefaction.