PRINCIPLES OF SOIL DYNAMICS
Second Edition
Braja M. Das - G. V. Ramana
14.6 MB
575 pag
PREFACE
1 INTRODUCTION 1
1.1 General 1
1.2 Nature and Type of Dynamic Loading on Soils 1
1.3 Importance of Soil Dynamics 4
References 6
2 FUNDAMENTALS OF VIBRATION 7
2.1 Introduction 7
2.2 Fundamentals of Vibration 8
System with Single Degree of Freedom 10
2.3 Free Vibration of a Spring-Mass System 10
2.4 Forced Vibration of a Spring-Mass System 16
2.5 Free Vibration with Viscous Damping 23
2.6 Steady-State Forced Vibration with Viscous Damping 30
2.7 Rotating-Mass-Type Excitation 35
2.8 Determination of Damping Ratio 37
2.9 Vibration-Measuring Instrument 40
System with Two Degrees of Freedom 42
2.10 Vibration of a Mass-Spring System 42
2.11 Coupled Translation and Rotation of a Mass-Spring System
(Free Vibration) 48
Problems 51
Reference 55
3 WAVES IN ELASTIC MEDIUM 56
3.1 Introduction 56
3.2 Stress and Strain 56
3.3 Hooke's Law 58
Elastic Stress Waves in a Bar 60
3.4 Longitudinal Elastic Waves in a Bar 60
3.5 Velocity of Particles in the Stressed Zone 63
3.6 Reflections of Elastic Stress Waves at the End of a Bar 65
3.7 Torsional Waves in a Bar 67
3.8 Longitudinal Vibration of Short Bars 68
3.9 Torsional Vibration of Short Bars 73
Stress Waves in an Infinite Elastic Medium 74
3.10 Equation of Motion in an Elastic Medium 74
3.11 Equations for Stress Waves 75
3.12 General Comments 78
Stress Waves in Elastic Half-Space 82
3.13 Rayleigh Waves 82
3.14 Displacement of Rayleigh Waves 88
3.15 Attenuation of the Amplitude of Elastic Waves with Distance 90
References 94
4 PROPERTIES OF DYNAMICALLY LOADED SOILS 96
4.1 Introduction 96
Laboratory Tests and Results
4.2 Shear Strength of Soils under Rapid Loading Condition 97
4.3 Strength and Deformation Characteristics of Soils under Transient Load 101
4.4 Travel−Time Test for Determination of Longitudinal and Shear Wave Velocities
(vc and vs) 104
4.5 Resonant Column Test 106
4.6 Cyclic Simple Shear Test 121
4.7 Cyclic Torsional Simple Shear Test 125
4.8 Cyclic Triaxial Test 128
4.9 Summary of Cyclic Tests 133
Field Test Measurements 135
4.10 Reflection and Refraction of Elastic Body Waves—Fundamental Concepts 135
4.11 Seismic Refraction Survey (Horizontal Layering) 137
4.12 Refraction Survey in Soils with Inclined Layering 145
4.13 Reflection Survey in Soil (Horizontal Layering) 151
4.14 Reflection Survey in Soil (Inclined Layering) 154
4.15 Subsoil Exploration by Steady-State Vibration 158
4.16 Soil Exploration by "Shooting Up the Hole," "Shooting Down the Hole," and
"Cross-Hole Shooting" 160
4.17 Cyclic Plate Load Test 164
Correlations for Shear Modulus and Damping Ratio 169
4.18 Test Procedures for Measurement of Moduli and Damping Characteristics 169
4.19 Shear Modulus and Damping Ratio in Sand 171
4.20 Correlation of Gmax of Sand with Standard Penetration Resistance 176
4.21 Shear Modulus and Damping Ratio for Gravels 176
4.22 Shear Modulus and Damping Ratio for Clays 178
4.23 Shear Modulus and Damping Ratio for Lightly Cemented Sand 186
Problems 188
References 192
5 FOUNDATION VIBRATION 196
5.1 Introduction 196
5.2 Vertical Vibration of Circular Foundations Resting on Elastic Half-Space—
Historical Development 196
5.3 Analog Solutions for Vertical Vibration of Foundations 205
5.4 Calculation Procedure for Foundation Response⎯Vertical Vibration 209
5.5 Rocking Vibration of Foundations 219
5.6 Sliding Vibration of Foundations 226
5.7 Torsional Vibration of Foundations 229
5.8 Comparison of Footing Vibration Tests with Theory 235
5.9 Comments on the Mass-Spring-Dashpot Analog Used for Solving Foundation
Vibration Problems 239
5.10 Coupled Rocking and Sliding Vibration of Rigid Circular Foundations 244
5.11 Vibration of Foundations for Impact Machines 248
Vibration of Embedded Foundations 251
5.12 Vertical Vibration of Rigid Cylindrical Foundations 251
5.13 Sliding Vibration of Rigid Cylindrical Foundations 256
5.14 Rocking Vibration of Rigid Cylindrical Foundations 257
5.15 Torsional Vibration of Rigid Cylindrical Foundations 259
Vibration Screening 261
5.16 Active and Passive Isolation: Definition 261
5.17 Active Isolation by Use of Open Trenches 261
5.18 Passive Isolation by Use of Open Trenches 264
5.19 Passive Isolation by Use of Piles 266
Problems 269
References 273
6 DYNAMIC BEARING CAPACITY OF SHALLOW FOUNDATIONS 276
6.1 Introduction 276
Ultimate Dynamic Bearing Capacity 277
6.2 Bearing Capacity in Sand 277
6.3 Bearing Capacity in Clay 283
6.4 Behavior of Foundations under Transient Loads 285
6.5 Experimental Observation of Load-Settlement Relationship for Vertical
Transient Loading 285
6.6 Seismic Bearing Capacity and Settlement in Granular Soil 291
Problems 297
References 298
7 EARTHQUAKE AND GROUND VIBRATION 300
7.1 Introduction 300
7.2 Definition of Some Earthquake-Related Terms 300
7.3 Earthquake Magnitude 303
7.4 Characteristics of Rock Motion during an Earthquake 305
7.5 Vibration of Horizontal Soil Layers with Linearly Elastic Properties 308
7.6 Other Studies for Vibration of Soil Layers Due to Earthquakes 319
7.7 Equivalent Number of Significant Uniform Stress Cycles for Earthquakes 320
References 324
8 LATERAL EARTH PRESSURE ON RETAINING WALLS 327
8.1 Introduction 327
8.2 Mononobe−Okabe Active Earth Pressure Theory 328
8.3 Some Comments on the Active Force Equation 335
8.4 Procedure for Obtaining PAE Using Standard Charts of KA 335
8.5 Effect of Various Parameters on the Value of the Active Earth Pressure
Coefficient 340
8.6 Graphical Construction for Determination of Active Force, PAE 342
8.7 Laboratory Model Test Results for Active Earth Pressure Coefficient, KAE 345
8.8 Point of Application of the Resultant Active Force, PAE 350
8.9 Design of Gravity Retaining Walls Based on Limited Displacement 353
8.10 Hydrodynamic Effects of Pore Water 361
8.11 Mononobe−Okabe Active Earth Pressure Theory for c − φ Backfill 363
8.12 Dynamic Passive Force on Retaining Wall 368
Problems 370
References 371
9 COMPRESSIBILITY OF SOILS UNDER DYNAMIC LOADS 374
9.1 Introduction 374
9.2 Compaction of Granular Soils: Effect of Vertical Stress and Vertical
Acceleration 374
9.3 Settlement of Strip Foundation on Granular Soil under the Effect of Controlled
Cyclic Vertical Stress 380
9.4 Settlement of Machine Foundation on Granular Soils Subjected to Vertical
Vibration 384
9.5 Settlement of Sand Due to Cyclic Shear Strain 389
9.6 Calculation of Settlement of Dry Sand Layers Subjected to Seismic Effect 391
9.7 Settlement of a Dry Sand Layer Due to Multidirectional Shaking 394
Problems 396
References 397
10 LIQUEFACTION OF SOIL 398
10.1 Introduction 398
10.2 Fundamental Concept of Liquefaction 399
10.3 Laboratory Studies to Simulate Field Conditions for Soil Liquefaction 401
Dynamic Triaxial Test 402
10.4 General Concepts and Test Procedures 402
10.5 Typical Results from Cyclic Triaxial Test 405
10.6 Influence of Various Parameters on Soil Liquefaction Potential 410
10.7 Development of Standard Curves for Initial Liquefaction 414
Cyclic Simple Shear Test 415
10.8 General Concepts 415
10.9 Typical Test Results 416
10.10 Rate of Excess Pore Water Pressure Increase 418
10.11 Large-Scale Simple Shear Tests 420
Development of a Procedure for Determination of Field Liquefaction 426
10.12 Correlation of the Liquefaction Results from Simple Shear and
Triaxial Tests 426
10.13 Correlation of the Liquefaction Results from Triaxial Tests to Field
Conditions 430
10.14 Zone of Initial Liquefaction in the Field 432
10.15 Relation between Maximum Ground Acceleration and the Relative
Density of Sand for Soil Liquefaction 433
10.16 Liquefaction Analysis from Standard Penetration Resistance 438
10.17 Other Correlations for Field Liquefaction Analysis 444
10.18 Remedial Action to Mitigate Liquefaction 447
Problems 454
References 455
11 MACHINE FOUNDATIONS ON PILES 459
11.1 Introduction 459
Piles Subjected to Vertical Vibration 460
11.2 End-Bearing Piles 460
11.3 Friction Piles 465
Sliding, Rocking, and Torsional Vibration 478
11.4 Sliding and Rocking Vibration 478
11.5 Torsional Vibration of Embedded Piles 492
Problems 501
References 504
12 SEISMIC STABILITY OF EARTH EMBANKMENTS 505
12.1 Introduction 505
12.2 Free Vibration of Earth Embankments 505
12.3 Forced Vibration of an Earth Embankment 509
12.4 Velocity and Acceleration Spectra 511
12.5 Approximate Method for Evaluation of Maximum Crest Acceleration and
Natural Period of Embankments 513
12.6 Fundamental Concepts of Stability Analysis 521
Pseudostatic Analysis 527
12.7 Clay Slopes (φ = 0 Condition)—Koppula's Analysis 527
12.8 Slopes with c − φ Soil—Majumdar's Analysis 532
12.9 Slopes with c − φ Soil—Prater's Analysis 540
12.10 Slopes with c − φ Soil—Conventional Method of Slices 543
Deformation of Slopes 546
12.11 Simplified Procedure for Estimation of Earthquake-Induced Deformation 546
Problems 549
References 551
APPENDIX A—PRIMARY AND SECONDARY FORCES OF SINGLE-CYLINDER
ENGINES 553
INDEX 556
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