Behavior of Pipe Piles in Sand: Plugging and Pore-Water Pressure Generation During Installation and Loading

284 Pages·2011·4.38 MB·English

by  Magued Iskander (auth.)

Springer Series in Geomechanics and
Geoengineering
Editors:WeiWu·RonaldoI.Borja
2 Using 360-degree Feedback in Organizations
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Magued Iskander
Behavior of Pipe Piles
in Sand
Plugging and Pore-Water Pressure
Generation During Installation and Loading
ABC
ProfessorWeiWu,InstitutfürGeotechnik,UniversitätfürBodenkultur, Feistmantelstraße
4,1180Vienna,Austria,E-mail:[email protected]
ProfessorRonaldoI.Borja,DepartmentofCivilandEnvironmentalEngineering,Stanford
University,Stanford,CA94305-4020,USA,E-mail:[email protected]
Author
MaguedIskander,PhD,PE,F.ASCE
CivilEngineeringDepartment
PolytechnicInstituteofNewYorkUniversity
SixMetrotechCenter
Brooklyn,NY11201
USA
E-mail:[email protected]
ISBN978-3-642-13107-3 e-ISBN978-3-642-13108-0
DOI 10.1007/978-3-642-13108-0
SpringerSeriesinGeomechanicsandGeoengineering ISSN1866-8755
(cid:2)c 2010Springer-VerlagBerlinHeidelberg
Thisworkissubjecttocopyright.Allrightsarereserved,whetherthewholeorpartofthematerialis
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orpartsthereofispermittedonlyundertheprovisionsoftheGermanCopyrightLawofSeptember9,
1965,initscurrentversion,andpermissionforusemustalwaysbeobtainedfromSpringer.Violations
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Theuseofgeneral descriptive names,registered names,trademarks, etc. inthis publication does not
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TypeDesignandCoverDesign:ScientificPublishingServicesPvt.Ltd.,Chennai,India.
Printedonacid-freepaper
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To
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Lolli, Kito,
& My Parents
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Contents
1 Introduction......................................................................................................1
1.1 Background................................................................................................1
1.2 Installation Effects That Influence the Capacity of Pipe Piles in Sand......2
1.2.1 Plugging of Piles.............................................................................2
1.2.2 Buildup of Pore Water Pressure......................................................3
1.3 Scope and Objectives.................................................................................4
1.4 Organization of This Book........................................................................4
References.................................................................................................5
2 Review of Design Guidelines for Piles in Sand………………………………7
2.1 Introduction...............................................................................................7
2.2 API Design Guidelines for Piles in Sand...................................................8
2.3 The Database...........................................................................................10
2.4 Analysis Using the 2000 API RP 2A.......................................................14
2.5 Assessment of the API Method for Piles in Sand....................................16
2.6 Sources of Inaccuracy in the API Method...............................................17
2.6.1 Statistical Considerations..............................................................17
2.6.2 Installation Effects........................................................................17
2.6.3 Axial Capacity Mechanism...........................................................18
2.6.3.1 Pile Movements...............................................................18
2.6.3.2 State of Stress in the Vicinity of the Pile.........................18
2.6.3.3 Friction Between Pile and Soil........................................19
2.6.3.4 Tension versus Compression...........................................20
2.6.3.5 Type and Rate of Loading...............................................20
2.6.4 Piles Driven through Clays into Sand...........................................20
2.7 Conclusions.............................................................................................21
References...............................................................................................21
3 Installation Effects on the Capacity of Piles in Sand………...…………….25
3.1 Introduction.............................................................................................25
3.2 Plugging of Piles......................................................................................25
3.2.1 Plugging of Piles during Installation.............................................26
3.2.2 Plugging of Piles during Static Loading........................................26
3.2.3 Plugging of Piles during Cyclic Loading......................................27
3.3 Buildup of Pore Pressures during Driving...............................................28
3.3.1 Excess Pore Pressures in Clays.....................................................28
VIII Contents
3.3.2 Excess Pore Pressures in Sands.....................................................28
3.3.3 Effects of Pile Setup on Drivability..............................................29
3.4 Stress Redistribution Due to Driving.......................................................29
3.5 Conclusions.............................................................................................30
References...............................................................................................31
4 Experimental Facilities to Study the Behavior of Piles................................35
4.1 Introduction..............................................................................................35
4.2 General Layout.........................................................................................36
4.3 The Pressure Chamber..............................................................................36
4.3.1 Design of the Pressure Chamber...................................................40
4.3.2 Preparation of Soil Specimens......................................................44
4.3.2.1 Sand Placement by Dry Pluviation.................................44
4.3.2.2 Saturation of the Soil Specimen......................................51
4.3.2.3 Sand Drying....................................................................55
4.3.3 Chamber Effects...........................................................................58
4.3.3.1 Size Effects.....................................................................58
4.3.3.2 Boundary Conditions......................................................59
4.3.3.3 Aging Effects..................................................................59
4.3.3.4 Wave Reflection Effects.................................................60
4.4 The Loading System.................................................................................60
4.4.1 The Loading Frame.......................................................................60
4.4.2 The Feedback Control System (Closed Loop)..............................62
4.4.2.1 The Hydraulic Power Source (Hydraulic Pump)............63
4.4.2.2 The Hydraulic Actuator (Hydraulic Ram)......................63
4.4.2.3 The Servovalve...............................................................63
4.4.2.4 The Load Cell.................................................................64
4.4.2.5 The Control Unit.............................................................64
4.5 The Data Acquisition System...................................................................65
4.5.1 The Computer...............................................................................65
4.5.2 Data Acquisition Hardware...........................................................65
4.5.3 Data Acquisition Software............................................................68
4.5.4 Signal Conditioning Equipment....................................................68
4.5.5 Sensors..........................................................................................70
4.5.5.1 Load................................................................................70
4.5.5.2 Displacement..................................................................70
4.5.5.3 Plug Movement...............................................................71
4.5.5.4 Strains & Pore Pressures.................................................71
4.6 Conclusions..............................................................................................73
References.................................................................................................73
5 Instrumented Double–Wall Pipe Pile to Study Behavior of Piles...............75
5.1 Introduction...............................................................................................75
5.2 The Double-Wall Concept.........................................................................76
5.3 Design of the Double-Wall Pile.................................................................79
5.3.1 Conceptual Design........................................................................79
Contents IX
5.3.2 Geometric Design.........................................................................82
5.3.3 Mechanical Design.......................................................................87
5.3.3.1 Axial Buckling................................................................88
5.3.3.2 In-plane Buckling Failure Mode.....................................91
5.4 Instrumentation..........................................................................................92
5.4.1 Instrumentation Layout.................................................................92
5.4.2 Instrumentation for Strain Measurements.....................................93
5.4.2.1 Selection of Strain Gages................................................93
5.4.2.2 Installation of Strain Gages.............................................96
5.4.3 Instrumentation for Pore-Pressure Measurements......................103
5.4.3.1 Selection of the Pore Pressure Transducers..................103
5.4.3.2 Design of Pore Pressure Transducers............................104
5.4.3.3 Operation of the Pore-Pressure Transducers.................107
5.4.4 Instrumentation Circuits..............................................................107
5.4.4.1 Strain Gage Circuits......................................................110
5.4.4.2 Pore-Pressure Transducer Circuits................................113
5.5 Protection from Driving Stresses.............................................................113
5.5.1 Solid State Encapsulation...........................................................114
5.5.1.1 Encapsulation of the Annular Space.............................114
5.5.1.2 Encapsulation of the Electrical Connections.................115
5.5.2 Bonding Instrumentation Wires to the Pile Walls.......................116
5.5.3 Stress Reduction in Electrical Connections................................116
5.6 Load Transfer between the Two Walls of the Pile...................................117
5.7 Calibration of the Double-Wall Pile........................................................120
5.7.1 Strain Gages................................................................................120
5.7.2 Pore Pressure Transducers..........................................................123
5.8 Conclusions.............................................................................................123
References………………………………………………………………124
6 Electro Pneumatic Laboratory Pile Hammer………………………….....127
6.1 Introduction...........................................................................................127
6.2 Background............................................................................................127
6.3 Special Considerations in the Design of Laboratory Pile Hammers......129
6.3.1 Type of Hammer.........................................................................129
6.3.2 Hammer Geometry......................................................................130
6.3.2.1 Hammer Shape..............................................................131
6.3.2.2 Length to Diameter Ratio..............................................132
6.3.2.3 Ram Weight...................................................................132
6.3.2.4 Location of the Control Unit..........................................133
6.4 Layout of the Driving System................................................................133
6.4.1 The Hammer...............................................................................133
6.4.2 The Leaders (Guide System).......................................................138
6.4.3 The Control Unit.........................................................................138
6.5 Mechanical Design of the Hammer.......................................................139
6.5.1 Wave Equation Analysis.............................................................139
6.5.2 Analysis of the Hammer’s Force-Time Signal............................148
6.6 Design of the Electro-Pneumatic Control System.................................150