GEOLOGIC CONTROLS OF SHEAR STRENGTH BEHAVIOR OF MUDROCKS A dissertation submitted to Kent State University in partial fulfillment of the requirements for the degree of Doctor of Philosophy By Ala’ M. Hajdarwish December 2006 Dissertation written by Ala’ M. Hajdarwish B. S., Yarmouk University, 1994 M. S., Yarmouk University, 1997 M. S., The University of Akron, 2001 Ph.D., Kent State University, 2006 Approved by , Chair, Doctoral Dissertation Committee Abdul Shakoor , Member, Doctoral Dissertation Committee Peter Dahl , Member, Doctoral Dissertation Committee Neil Wells , Member, Doctoral Dissertation Committee Mandy Munro-Stasiuk , Graduate College Representative and Moderator Richard Meindl Accepted by , Chair, Department of Geology Donald Palmer , Dean, College of Arts and Sciences John R. D. Stalvey ii TABLE OF CONTENTS LIST OF FIGURES ...........................................................................................................vi LIST OF TABLES...........................................................................................................viii ACKNOWLEDGEMENTS...............................................................................................ix INTRODUCTION .............................................................................................................. 1 Geologic Classification of Mudrocks ..................................................................... 3 Related Research..................................................................................................... 4 Objectives ............................................................................................................... 7 RESEARCH METHODS .................................................................................................8 Sampling ...............................................................................................................10 Laboratory Investigations .....................................................................................12 Natural Water Content Test ......................................................................13 Direct Shear Test.......................................................................................13 Grain Size Distribution Analysis ..............................................................13 X-ray Diffraction Analysis .......................................................................16 Dry Density, Specific Gravity, and Void Ratio Determinations ..............18 Absorption Test.........................................................................................20 Adsorption Test.........................................................................................21 Atterberg Limits Test................................................................................22 Slake Durability Index Test ......................................................................22 Data Analysis........................................................................................................23 Univariate Analysis...................................................................................23 Correlation Analysis .................................................................................24 Regression Analysis..................................................................................25 RESULTS OF DIRECT SHEAR TESTING....................................................................26 Cohesion ...............................................................................................................26 Friction Angle .......................................................................................................33 RESULTS OF LITHOLOGIC AND ENGINEERING TESTING ..................................41 iii Results of Lithologic Testing................................................................................41 Grain Size Distribution ............................................................................41 X-ray Diffraction Analysis Results...........................................................43 Results of Engineering Testing.............................................................................53 Natural Water Content .............................................................................53 Dry Density, Specific Gravity, and Void Ratio ........................................53 Absorption.................................................................................................55 Adsorption.................................................................................................56 Atterberg Limits........................................................................................57 Slake Durability ........................................................................................58 DATA ANALYSIS OF All MUDROCKS.......................................................................61 Analysis of Mudrock Data....................................................................................61 Univariate Analysis....................................................................................61 Correlation Analysis .............................................................................. ..62 Multivariate Regression analysis ..............................................................66 Multivariate Regression Analysis for Cohesion ...........................66 Multivariate Regression Analysis for Friction Angle...................73 DISCUSSION...................................................................................................................80 Limitations ............................................................................................................86 SUMMARY AND CONCLUSIONS ...............................................................................87 REFERENCES .................................................................................................................90 APPENDICES APPENDIX A: SITE LOCATION AND DESCRIPTION OF SAMPLES .........95 APPENDIX B: DIRECT SHEAR TEST DATA............................................... 104 APPENDIX C: GRAIN SIZE DISTRIBUTION RESULTS............................. 132 APPENDIX D: X-RAY DIFFRACTION ANALYSIS RESULTS................... 160 APPENDIX E: WATER CONTENT DATA .................................................... 166 APPENDIX F: DRY DENSITY, SPECIFIC GRAVITY, VOID RATIO DATA .......................................................................... 170 APPENDIX G: ABSORPTION DATA............................................................. 177 APPENDIX H: ADSORPTION DATA ............................................................ 181 iv APPENDIX I: ATTERBERG LIMITS RESULTS .......................................... 185 APPENDIX J: SLAKE DURABILITY TEST RESULTS................................ 189 APPENDIX K: UNIVARIATE DATA ANALYSIS RESULTS...................... 193 APPENDIX L: BIVARIATE PLOTS ............................................................... 199 v LIST OF FIGURES Figure Page 1 Sample location map.......................................................................................... 12 2 Cross-sectional view of mudrock sample in the shear box................................ 14 3 Stress-strain plots for a mudrock sample under three different values of normal loads .................................................................................................. 15 4 Shear stress vs normal load plot used to obtain c and φ values ......................... 15 5 Distribution of cohesion values for all mudrocks.............................................. 28 6 Distribution of cohesion values for claystones .................................................. 29 7 Distribution of cohesion values for mudstones.................................................. 30 8 Distribution of cohesion values for siltstones.................................................... 31 9 Distribution of cohesion values for shales......................................................... 32 10 Distribution of friction angle values for all mudrocks....................................... 35 11 Distribution of friction angle values for claystones........................................... 36 12 Distribution of friction angle values for mudstones .......................................... 37 13 Distribution of friction angle values for siltstones............................................. 38 14 Distribution of friction angle values for shales.................................................. 39 15 X-ray diffractogram for claystone sample (S-10): (a) non-treated, (b) glycolated (c) heated at 350 ° C, (d) heated at 550 ° C.................................. 45 16 X-ray diffractogram for mudstone sample (S-1): (a) non-treated, (b) glycolated(c) heated at 350 ° C, (d) heated at 550 ° C................................... 47 17 X-ray diffractogram for siltstone sample (S-2): (a) non-treated, (b) glycolated(c) heated at 350 ° C, (d) heated at 550 ° C................................... 49 vi Figure Page 18 X-ray diffractogram of shale sample (S-32); (a) non-treated, (b) glycolated(c) heated at 350 ° C, (d) heated at 550 ° C................................... 51 19a Plot of regression model number and corresponding adjusted R 2 values with respect to cohesion. Refer to Table 37 for explanations of each model .... 68 19b Plot of number of variables in each model and corresponding adjusted R 2 values with respect to cohesion. Refer to Table 37 for identification of variables ............................................................................................................