Behavior of Pipe Piles in Sand (eBook)

Title Page 1
Contents 5
Acknowledgements 10
Selected Unit Conversions 11
Introduction 13
Background 13
Installation Effects That Influence the Capacity of Pipe Piles in Sand 14
Plugging of Piles 14
Buildup of Pore Water Pressure 15
Scope and Objectives 16
Organization of This Book 16
References 17
Review of Design Guidelines for Piles in Sand 19
Introduction 19
API Design Guidelines for Piles in Sand 20
The Database 22
Analysis Using the 2000 API RP 2A 26
Assessment of the API Method for Piles in Sand 28
Sources of Inaccuracy in the API Method 29
Statistical Considerations 29
Installation Effects 29
Axial Capacity Mechanism 30
Piles Driven through Clays into Sand 32
Conclusions 33
References 33
Installation Effects on the Capacity of Piles in Sand 36
Introduction 36
Plugging of Piles 36
Plugging of Piles during Installation 37
Plugging of Piles during Static Loading 37
Plugging of Piles during Cyclic Loading 38
Buildup of Pore Pressures during Driving 39
Excess Pore Pressures in Clays 39
Excess Pore Pressures in Sands 39
Effects of Pile Setup on Drivability 40
Stress Redistribution Due to Driving 40
Conclusions 41
References 42
Experimental Facilities to Study the Behavior of Piles 45
Introduction 45
General Layout 46
The Pressure Chamber 46
Design of the Pressure Chamber 50
Preparation of Soil Specimens 54
Chamber Effects 68
The Loading System 70
The Loading Frame 70
The Feedback Control System (Closed Loop) 72
The Data Acquisition System 75
The Computer 75
Data Acquisition Hardware 75
Data Acquisition Software 78
Signal Conditioning Equipment 78
Sensors 80
Conclusions 83
References 83
Instrumented Double–Wall Pipe Pile to Study Behavior of Piles 84
Introduction 84
The Double-Wall Concept 85
Design of the Double-Wall Pile 88
Conceptual Design 88
Geometric Design 91
Mechanical Design 96
Instrumentation 101
Instrumentation Layout 101
Instrumentation for Strain Measurements 102
Instrumentation for Pore-Pressure Measurements 112
Instrumentation Circuits 116
Protection from Driving Stresses 122
Solid State Encapsulation 123
Bonding Instrumentation Wires to the Pile Walls 125
Stress Reduction in Electrical Connections 125
Load Transfer between the Two Walls of the Pile 126
Calibration of the Double-Wall Pile 129
Strain Gages 129
Pore Pressure Transducers 132
Conclusions 132
References 133
Electro Pneumatic Laboratory Pile Hammer 135
Introduction 135
Background 135
Special Considerations in the Design of Laboratory Pile Hammers 137
Type of Hammer 137
Hammer Geometry 138
Layout of the Driving System 141
The Hammer 141
The Leaders (Guide System) 146
The Control Unit 146
Mechanical Design of the Hammer 147
Wave Equation Analysis 147
Analysis of the Hammer’s Force-Time Signal 156
Design of the Electro-Pneumatic Control System 158
Basic Principles of Gaseous Fluid Flow 158
Selection of the Pneumatic Components 160
The Electro-Pneumatic Circuit 162
Performance of the Hammer 166
Raw Performance of the Hammer 166
Hammer Performance during Pile Driving 173
Conclusions 181
References 182
Geotechnical Properties of the Testing Sand 185
Introduction 185
Preliminary Choices 185
Selection of the Test Sand 186
Geotechnical Properties of Oklahoma Sand 187
Physical Properties 187
Shear Strength 189
Hydraulic Conductivity 189
Changes in Sand Properties Due to Recycling 193
References 194
Similitude between Model and Full Scale Piles 195
Introduction 195
Similitude 195
Scaling Laws 196
Modeling Capabilities of the Experimental Facilities 196
Modeling of Earth Stresses in the Pressure Chamber 199
Modeling of Pile Driving Using the Hammer 200
Conclusions 202
References 202
Load Tests Using the Double–Wall Pipe Pile in Sand 203
Introduction 203
Test Procedure 203
Data Presentation 204
Stresses and Pore Pressures 204
Plug Measurements 205
Load Tests on the Pile Pushed (Jacked) in Dry Sand 206
Jacking (Pushing) Stage 206
Load Test 217
Pull-Out Test 218
Load Tests on the Pile Pushed (Jacked) in Saturated Sand 218
Jacking (Pushing) Stage 231
Load Test 231
Pull-Out Test 232
Load Tests on the Pile Driven in Saturated Sand 233
Driving Stage 233
Load Test 248
Pull-Out Test 249
Observed Behavior of Piles in Sand 249
Pile Plugging 249
Buildup of Pore Pressures 250
Load Transfer 250
Conclusions 250
References 251
Summary and Conclusions 252
Background 252
Summary 253
Conclusions 254
Conclusions Regarding Experimental Apparatus 254
Conclusions Regarding the Behavior of Piles in Sand 255
Recommendations for Future Research 256
References 256
References 257
Index 268