Ground Support Technology for Highly Stressed Excavations: Integrated Theoretical, Laboratory, and Field Research

Cover
Half Title
Title
Copyright
Contents
About the Authors
Foreword
Preface
Acknowledgements
Chapter 1 Introduction
	1.1 Introduction
	1.2 The Process of Support and Reinforcement
	1.3 Brief History of Ground Support Technology
	1.4 Scope and Contents of This Book
Chapter 2 Terminology
	2.1 Introduction
	2.2 Reinforcement System Response
	2.3 Continuous Mechanically Coupled
	2.4 Continuous Frictionally Coupled
	2.5 Discrete Mechanically or Frictionally Coupled
	2.6 The Load Transfer Concept
	2.7 The Embedment Length Concept
	2.8 Materials Behaviour Terminology
		2.8.1 Elastic
		2.8.2 Plastic
		2.8.3 Brittle
		2.8.4 Ductile
		2.8.5 Resilience
		2.8.6 Toughness
		2.8.7 Yield
		2.8.8 Stiffness
	2.9 Performance Indicators of Capacity
	2.10 Surface Support System Response
		2.10.1 Type of Support Systems
			2.10.1.1 Point Support Systems
			2.10.1.2 Strip Support Systems
			2.10.1.3 Areal Support Systems
		2.10.2 Loading Mechanisms
		2.10.3 Load Transfer Concepts
			2.10.3.1 Point Support Systems
			2.10.3.2 Strip and Areal Support Systems
Chapter 3 Probabilistic Simulation of Rock Mass Demand
	3.1 Introduction
	3.2 Rock Mass Characterization
		3.2.1 Geotechnical Mapping of Underground Exposures
	3.3 Rock Mass Model
	3.4 Deterministic Assessment of Rock Mass Instabilities
	3.5 Probabilistic Assessment of Rock Mass Instabilities
		3.5.1 Interpretation of Results
Chapter 4 Ground Support Mechanics
	4.1 Introduction
	4.2 Reinforcement Response
		4.2.1 Load Transfer within the Collar Region
		4.2.2 Load Transfer along the Element and at the Toe Anchor Region
	4.3 Surface Support Response
	4.4 Failure Geometry
	4.5 Surface Layer Toughness
	4.6 Ground Support Scheme
Chapter 5 Ground Support Design
	5.1.Introduction
	5.2.Rock Mass Characterization
		5.2.1.Structure
		5.2.2.Strength
	5.3.Tunnel Instability
		5.2.1.Spalling Failure
		5.2.2.Structurally Controlled Failure
		5.2.3.Damage and Deformation Prior to Violent Failure
	5.3.Ejection Velocity
	5.4.Ground Support Demand
		5.4.1.Shallow Depth of Failure (Spalling)
		5.4.2.Structurally Controlled Depth of Failure
	5.5.Ground Support Capacity
	5.5.1.Ground Support Design for Extremely High Demand Conditions
Chapter 6 Laboratory Testing
	6.1 Introduction
	6.2 Testing Documentation
	6.3 Component Testing
	6.4 Element Testing
		6.4.1 Prestressing Strand
		6.4.2 Solid Threaded Bar
	6.5 Internal Fixture Testing
		6.5.1 Slot and Wedge Anchors
		6.5.2 Expansion Shell Anchors
		6.5.3 Cement Grouts
		6.5.4 Resin Grouts
	6.6 External Fixture Testing
		6.6.1 Split Tube Rings
		6.6.2 Barrel and Wedge Strand Anchors
		6.6.3 Plates
	6.7 Systems Testing
		6.7.1 Cable Bolt Pull Tests
		6.7.2 Resin-Encapsulated Reinforcement Ł
	6.8 WASM Dynamic Test Facility
		6.8.1 Force Transfer and Displacement
		6.8.2 Simulated Boreholes and Sample Installation
		6.8.3 Dynamic Test Results
		6.8.4 Analysis of Dynamic Test Results
		6.8.5 Dynamic Testing of Mesh and Shotcrete Layers
Chapter 7 Energy Dissipation of Rock Bolts
	7.1 Introduction
	7.2 Momentum Transfer
	7.3 Reinforcement System Load Transfer
	7.4 Continuously Frictionally Coupled
		7.4.1 Friction Rock Stabilizer
			7.4.1.1 Static Testing
			7.4.1.2 Dynamic Testing
		7.4.2 Expanded Tube Bolts
			7.4.2.1 Static Testing
			7.4.2.2 Dynamic Testing
		7.4.3 Hybrid Point Anchored Bar and Split Tube Bolts
			7.4.3.1 Borehole Simulation and Installation
			7.4.3.2 Dynamic Testing
	7.5 Continuously Mechanically Coupled
		7.5.1 Cement-Encapsulated Threaded Bar
			7.5.1.1 Australian Threaded Bar
			7.5.1.2 Chilean Threaded Bar
		7.5.2 Resin-Encapsulated Threaded Bar
	7.6 Discretely Mechanically or Frictionally Coupled
		7.6.1 Cement-Encapsulated Decoupled Threaded Bar
		7.6.2 Resin-Encapsulated Decoupled Posimix
		7.6.3 Cement- and Resin-Encapsulated D Bolt
		7.6.4 Cement- and Resin-Encapsulated Cone Bolt
		7.6.5 Cement- and Resin-Encapsulated Garford Dynamic Bolt
		7.6.6 Cement-Encapsulated Durabar Bolt
		7.6.7 Cement-Encapsulated Yield-Lok Bolt
		7.6.8 Self-Drilling Anchor Bolt
Chapter 8 Energy Dissipation of Cable Bolts
	8.1 Introduction
	8.2 Cement Grout
		8.2.1 Physical and Mechanical Properties
			8.2.1.1 Fresh Cement Paste
			8.2.1.2 Hardened Cement
		8.2.2 Grouting Reinforcement Boreholes
			8.2.2.1 Toe-to-Collar Grouting
			8.2.2.2 Mechanized Grouting
		8.3 Cable Bolt Types
			8.3.1 Modified Strand Cable Bolts
			8.3.2 Plain Strand—15.2 mm Diameter
			8.3.3 Plain Strand—17.8 mm Diameter
			8.3.4 Decoupled Strand
			8.3.5 Multiple Dynamic Impact Testing
		8.4 Cable Bolt Plates
			8.4.1 Barrel and Wedge Anchors
				8.4.1.1 Anchor Installation
				8.4.1.2 Anchor Mechanism and Performance
			8.4.2 Dynamic Testing Results
Chapter 9 Energy Dissipation of Mesh Support
	9.1 Introduction
	9.2 Mesh Load Transfer
	9.3 Mesh Testing
		9.3.1 Boundary Conditions
		9.3.2 Loading Method
	9.4 Mesh Force and Displacement
		9.4.1 Static Results for Welded Wire Mesh
		9.4.2 Static Results for Woven Mesh
		9.4.3 Dissipated Static Energy
		9.4.4 Dynamic Results for Welded Wire Mesh
		9.4.5 Dynamic Results for Woven Mesh
		9.4.6 Dissipated Dynamic Energy
Chapter 10 Energy Dissipation of Shotcrete Support
	10.1 Introduction
	10.2 Shotcrete Mix Design
	10.3 Material Properties
		10.3.1 Cement
		10.3.2 Mechanism of Hydration of Cement
		10.3.3 Supplementary Cementing Materials
			10.3.3.1 Silica Fume
			10.3.3.2 Fly Ash
			10.3.3.3 Slag Cement
		10.3.4 Mixing Water
		10.3.5 Aggregate
		10.3.6 Fibres
			10.3.6.1 Steel Fibres
			10.3.6.2 Synthetic Fibres
		10.3.7 Admixtures
			10.3.7.1 Accelerator
			10.3.7.2 Superplasticizer
			10.3.7.3 Air-Entraining
			10.3.7.4 Hydration Stabilizer
	10.4 Shotcrete Support System
		10.4.1 Rock Surface and Shotcrete Profiles
		10.4.2 Deformation Mechanisms
	10.5 Static Performance of Freshly Sprayed Shotcrete
		10.5.1 Review of Shotcrete Early Strength
		10.5.2 Shear Strength of Freshly Sprayed Shotcrete
			10.5.2.1 Development of Shear Strength of Shotcrete Paste with and without the Influence of a Chemical Admixture
			10.5.2.2 Development of Shear Strength of Shotcrete Paste with Various Combinations of Mixed Components
		10.5.3 Structural Requirements for a Freshly Sprayed Shotcrete Layer
			10.5.3.1 Requirements for Self-Support
			10.5.3.2 Required Shotcrete Shear Strength for Self-Weight and Block Support
		10.5.4 Safe Re-entry Time
	10.6 Static Performance of Cured Shotcrete
		10.6.1 Uniaxial Compressive Strength (UCS)
		10.6.2 Tensile Strength
		10.6.3 Tensile Bond Strength of Rock—Shotcrete Interface
		10.6.4 Shear Strength
		10.6.5 Toughness
	10.7 Shotcrete Failure Mechanisms
		10.7.1 Shotcrete Load Transfer
	10.8 Large Scale Static Testing
	10.9 Large Scale Dynamic Testing
		10.9.1 Shotcrete Test Set-Up
		10.9.2 Shotcrete Failure Mechanism
		10.9.3 Shotcrete Energy Dissipation
			10.9.3.1 Fibre-Reinforced Shotcrete
			10.9.3.2 Mesh-Reinforced Shotcrete
Chapter 11 Dynamic Performance of Ground Support Schemes
	11.1 Introduction
	11.2 Load Transfer
	11.3 Free Body Diagrams
	11.4 Combined Reinforcement and Mesh Schemes
		11.4.1 Sample Preparation and Testing
		11.4.2 Data Analysis
		11.4.3 Data
			11.4.3.1 Cement-Encapsulated Rebar and G80/4 Mesh
			11.4.3.2 Cement-Encapsulated Rebar and Welded Wire Mesh
			11.4.3.3 Decoupled Posimix and Welded Wire Mesh
			11.4.3.4 Decoupled Posimix and Woven Mesh
		11.4.4 Summary of Energy Dissipation
	11.5 Large-Scale Testing of Full-Scale Schemes
Chapter 12 Reinforced Block Analysis
	12.1 Introduction
	12.2 Description of the Problem
	12.3 Reinforcement Response at a Block Face
	12.4 Reinforcement Databases
		12.4.1 A Generic Reinforcement System
		12.4.2 Measurement of Reinforcement System Responses
		12.4.3 Reinforcement System Simulations
		12.4.4 Reinforcement System Responses
			12.4.4.1 Component Properties
			12.4.4.2 Interface Properties
			12.4.4.3 Variations of Axial Force-Displacement Responses with Encapsulation Length
			12.4.4.4 Axial Force-Displacement Responses with External Fixture and Encapsulation Lengths
		12.4.5 Application of the Reinforcement Databases in Design for a Reinforced Block
			12.4.5.1 Description of the Analysis
			12.4.5.2 Estimation of Force-Displacement Responses
	12.5 Static Analysis of a Reinforced Arbitrarily-Shaped Block
		12.5.1 The Design Problem
		12.5.2 Description of the Analysis Method
	12.6 Dynamic Block Loading
		12.6.1 Newtonian Mechanics-Based Analysis
		12.6.2 Momentum-Based Analysis
		12.6.3 Energy-Based Analysis
		12.6.4 Summary of Dynamic Analysis Methods
	12.7 Displacement Controlled Dynamic Analysis Methodology
	12.8 Example of Implemented Theory
		12.8.1 Description of the Analysis
		12.8.2 Imposed Loading and Results
Chapter 13 Construction and Monitoring
	13.1 Introduction
	13.2 Induced Stress
	13.3 Construction
		13.3.1 Excavation Shape
		13.3.2 De-Stress Blasting
			13.3.2.1 Mechanics
			13.3.2.2 De-stress Blasting Patterns
			13.3.2.3 Explosive Energy
			13.3.2.4 Micro Seismic Activity
			13.3.2.5 Geotechnical Concerns
			13.3.2.6 Case Study—Kanowna Belle Mine, WA, Australia
		13.3.3 Construction of a High Energy Dissipation Ground Support Scheme
			13.3.3.1 Clearing of Temporary Face Support
			13.3.3.2 Mechanical Scaling
			13.3.3.3 Structural Geological Mapping with Photogrammetry
			13.3.3.4 Shotcrete Application
			13.3.3.5 Primary Reinforcement Mark-Up
			13.3.3.6 Installation of Primary Reinforcement and Mesh
			13.3.3.7 Primary to Secondary Support Installation Sequence
			13.3.3.8 Final Ground Support Scheme Arrangement
		13.4 Monitoring
			13.4.1 Drilling and Blasting
			13.4.2 Deformation
References
Index