Iskander Behavior of Pipe Piles in Sand

Plugging & Pore-Water Pressure Generation During Installation and Loading
1. Auflage 2011
ISBN: 978-3-642-13108-0
Verlag: Springer
Format: PDF
Kopierschutz: 1 - PDF Watermark

E-Book, Englisch, 269 Seiten

Reihe: Springer Series in Geomechanics and Geoengineering

One of the major difficulties in predicting the capacity of pipe piles in sand has resulted from a lack of understanding of the physical processes that control the behavior of piles during installation and loading.This monograph presents a detailed blue print for developing experimental facilities necessary to identify these processes. These facilities include a unique instrumented double-walled pipe-pile that is used to delineate the frictional stresses acting against the external and internal surfaces of the pile. The pile is fitted with miniature pore-pressure transducers to monitor the generation of pore water pressure during installation and loading. A fast automatic laboratory pile hammer capable of representing the phenomena that occur during pile driving was also developed and used.

Autoren/Hrsg.

Iskander, Magued

Inhaltsverzeichnis

1;Title Page;1
2;Contents;5
3;Acknowledgements;10
4;Selected Unit Conversions;11
5;Introduction;13
5.1;Background;13
5.2;Installation Effects That Influence the Capacity of Pipe Piles in Sand;14
5.2.1;Plugging of Piles;14
5.2.2;Buildup of Pore Water Pressure;15
5.3;Scope and Objectives;16
5.4;Organization of This Book;16
5.5;References;17
6;Review of Design Guidelines for Piles in Sand;19
6.1;Introduction;19
6.2;API Design Guidelines for Piles in Sand;20
6.3;The Database;22
6.4;Analysis Using the 2000 API RP 2A;26
6.5;Assessment of the API Method for Piles in Sand;28
6.6;Sources of Inaccuracy in the API Method;29
6.6.1;Statistical Considerations;29
6.6.2;Installation Effects;29
6.6.3;Axial Capacity Mechanism;30
6.6.4;Piles Driven through Clays into Sand;32
6.7;Conclusions;33
6.8;References;33
7;Installation Effects on the Capacity of Piles in Sand;36
7.1;Introduction;36
7.2;Plugging of Piles;36
7.2.1;Plugging of Piles during Installation;37
7.2.2;Plugging of Piles during Static Loading;37
7.2.3;Plugging of Piles during Cyclic Loading;38
7.3;Buildup of Pore Pressures during Driving;39
7.3.1;Excess Pore Pressures in Clays;39
7.3.2;Excess Pore Pressures in Sands;39
7.3.3;Effects of Pile Setup on Drivability;40
7.4;Stress Redistribution Due to Driving;40
7.5;Conclusions;41
7.6;References;42
8;Experimental Facilities to Study the Behavior of Piles;45
8.1;Introduction;45
8.2;General Layout;46
8.3;The Pressure Chamber;46
8.3.1;Design of the Pressure Chamber;50
8.3.2;Preparation of Soil Specimens;54
8.3.3;Chamber Effects;68
8.4;The Loading System;70
8.4.1;The Loading Frame;70
8.4.2;The Feedback Control System (Closed Loop);72
8.5;The Data Acquisition System;75
8.5.1;The Computer;75
8.5.2;Data Acquisition Hardware;75
8.5.3;Data Acquisition Software;78
8.5.4;Signal Conditioning Equipment;78
8.5.5;Sensors;80
8.6;Conclusions;83
8.7;References;83
9;Instrumented Double–Wall Pipe Pile to Study Behavior of Piles;84
9.1;Introduction;84
9.2;The Double-Wall Concept;85
9.3;Design of the Double-Wall Pile;88
9.3.1;Conceptual Design;88
9.3.2;Geometric Design;91
9.3.3;Mechanical Design;96
9.4;Instrumentation;101
9.4.1;Instrumentation Layout;101
9.4.2;Instrumentation for Strain Measurements;102
9.4.3;Instrumentation for Pore-Pressure Measurements;112
9.4.4;Instrumentation Circuits;116
9.5;Protection from Driving Stresses;122
9.5.1;Solid State Encapsulation;123
9.5.2;Bonding Instrumentation Wires to the Pile Walls;125
9.5.3;Stress Reduction in Electrical Connections;125
9.5.4;Load Transfer between the Two Walls of the Pile;126
9.6;Calibration of the Double-Wall Pile;129
9.6.1;Strain Gages;129
9.6.2;Pore Pressure Transducers;132
9.7;Conclusions;132
9.8;References;133
10;Electro Pneumatic Laboratory Pile Hammer;135
10.1;Introduction;135
10.2;Background;135
10.3;Special Considerations in the Design of Laboratory Pile Hammers;137
10.3.1;Type of Hammer;137
10.3.2;Hammer Geometry;138
10.4;Layout of the Driving System;141
10.4.1;The Hammer;141
10.4.2;The Leaders (Guide System);146
10.4.3;The Control Unit;146
10.5;Mechanical Design of the Hammer;147
10.5.1;Wave Equation Analysis;147
10.5.2;Analysis of the Hammer’s Force-Time Signal;156
10.6;Design of the Electro-Pneumatic Control System;158
10.6.1;Basic Principles of Gaseous Fluid Flow;158
10.6.2;Selection of the Pneumatic Components;160
10.6.3;The Electro-Pneumatic Circuit;162
10.7;Performance of the Hammer;166
10.7.1;Raw Performance of the Hammer;166
10.7.2;Hammer Performance during Pile Driving;173
10.8;Conclusions;181
10.9;References;182
11;Geotechnical Properties of the Testing Sand;185
11.1;Introduction;185
11.2;Preliminary Choices;185
11.3;Selection of the Test Sand;186
11.4;Geotechnical Properties of Oklahoma Sand;187
11.4.1;Physical Properties;187
11.4.2;Shear Strength;189
11.4.3;Hydraulic Conductivity;189
11.4.4;Changes in Sand Properties Due to Recycling;193
11.5;References;194
12;Similitude between Model and Full Scale Piles;195
12.1;Introduction;195
12.2;Similitude;195
12.3;Scaling Laws;196
12.4;Modeling Capabilities of the Experimental Facilities;196
12.4.1;Modeling of Earth Stresses in the Pressure Chamber;199
12.4.2;Modeling of Pile Driving Using the Hammer;200
12.5;Conclusions;202
12.6;References;202
13;Load Tests Using the Double–Wall Pipe Pile in Sand;203
13.1;Introduction;203
13.2;Test Procedure;203
13.3;Data Presentation;204
13.3.1;Stresses and Pore Pressures;204
13.3.2;Plug Measurements;205
13.4;Load Tests on the Pile Pushed (Jacked) in Dry Sand;206
13.4.1;Jacking (Pushing) Stage;206
13.4.2;Load Test;217
13.4.3;Pull-Out Test;218
13.5;Load Tests on the Pile Pushed (Jacked) in Saturated Sand;218
13.5.1;Jacking (Pushing) Stage;231
13.5.2;Load Test;231
13.5.3;Pull-Out Test;232
13.6;Load Tests on the Pile Driven in Saturated Sand;233
13.6.1;Driving Stage;233
13.6.2;Load Test;248
13.6.3;Pull-Out Test;249
13.7;Observed Behavior of Piles in Sand;249
13.7.1;Pile Plugging;249
13.7.2;Buildup of Pore Pressures;250
13.7.3;Load Transfer;250
13.8;Conclusions;250
13.9;References;251
14;Summary and Conclusions;252
14.1;Background;252
14.2;Summary;253
14.3;Conclusions;254
14.3.1;Conclusions Regarding Experimental Apparatus;254
14.3.2;Conclusions Regarding the Behavior of Piles in Sand;255
14.4;Recommendations for Future Research;256
14.5;References;256
15;References;257
16;Index;268