Mining Subsidence Engineering

I Strata Movement.- 1. Strata Movement at the Mining Horizon.- 1.1 Mining Methods, from the Standpoint of Subsidence.- 1.2 Convergence in the Workings.- 1.2.1 Mining Without Permanent Pillars (Total Extraction).- 1.2.2 Mining with Permanent Pillars (Partial Extraction).- 1.3 Factors Influencing Convergence in the Workings.- 1.4 Horizontal Movement in the Roof Stratum.- 2. Deformation of the Rock Mass.- 2.1 Zones of Movement in the Overlying Beds.- 2.2 Vertical Movement and Deformation.- 2.3 Horizontal Movement and Deformation.- 2.4 Rock Kinematics in Steep-lying Measures.- 2.5 Surface Fracture over Shallow Workings.- 2.6 Chronological Stages in Strata Movement.- 3. The Calculation of Strata Movement.- 3.1 General Assumptions in Calculation Procedures.- 3.2 Calculating Convergence in the Workings.- 3.2.1 The Roof as an Overlying Beam.- 3.2.2 A Roof of Loose Rock.- 3.2.3 The Roof as a Kelvin Body.- 3.2.4 Empirical Formulae for Convergence in the Workings.- 3.3 The Pre-Calculation of Strata Movement.- 3.3.1 The Integration-grid, or Influence-Function, Method.- 3.3.2 The Rock Mass as an Elastic Material.- 3.3.3 The Rock Mass as an Inelastic Material.- 3.3.4 The Rock Mass as a Stochastic Medium.- 3.3.5 The Rock Mass as Finite Elements.- 4. Strata Movement at the Shaft.- 4.1 Subsidence Damage to the Shaft Lining.- 4.2 Bases of the Calculation Procedure.- 4.3 Calculation of Shaft Stress.- 4.4 Superposed Mining Influences; and Tilt.- 4.5 Extent of Vertical Expansion and Contraction in Strata.- 5. Systematic Mining of the Shaft Safety-pillar.- 5.1 Measures to Protect the Shaft.- 5.2 The Mining Plan for the Shaft Safety Zone.- 5.3 Protecting the Shaft Lining Against Mining Damage.- 6. The Influence of Previous Workings and Mining Practice on Strata Movement.- 6.1 The Reciprocal Influence of Workings.- 6.2 The Border Effects of Neighbouring Workings.- 6.3 Changes in Convergence with Multilevel Workings.- 6.4 Coal-pillar Pressure in a Panel.- 6.5 The Influence of Mining Procedures on the Break-up of the Rock Fabric.- 6.6 The Swelling of Clay-bearing Beds.- II The Study of Ground Movement.- 7. The Components of Ground Movement.- 7.1 Historical Development.- 7.2 Ground Movement with Flat-lying Measures.- 7.2.1 Shape of the Trough.- 7.2.2 Calculation of Trough Components.- 7.3 Anomalies in the Trough Outline.- 7.4 Ground Movement in Steep-lying Measures.- 8. The Pre-calculation of Ground Subsidence.- 8.1 Varieties of Calculation Procedure.- 8.2 Empirical Methods.- 8.2.1 The Angle-of-Intersection Method.- 8.2.2 The British Profile-curve Method.- 8.2.3 The Russian Profile-curve Method.- 8.2.4 The Polish Profile-curve Method.- 8.2.5 The Hungarian Profile-curve Method.- 8.2.6 The Programmed Profile-curve Method.- 8.2.7 The Empirical Integration-grid Method.- 8.3 Methods Employing Influence Functions.- 8.3.1 The Theoretical Basis.- 8.3.2 The Graphical Method in Flat-lying Measures.- 8.3.3 Methods for Adapting to Distorted Superposition.- 8.3.4 Integration Grids in Steep-lying Measures.- 8.3.5 Semi-graphical Methods, and Methods Employing Analogues.- 8.3.6 Programmed Calculation of the Influence Factor.- 8.4 Methods Employing Theoretical Models.- 8.4.1 The Stochastic Model.- 8.4.2 The Elastic Model.- 8.4.3 The Plastic Model.- 8.4.4 The Finite-Elements Model.- 9. Pre-calculation of Ground Displacement.- 9.1 Special Features of Displacement Calculation.- 9.2 The Focal-Point Method.- 9.3 The Method with Influence Functions.- 9.3.1 Deriving the Grid from the Focal-point Formula.- 9.3.2 Deriving Displacement from Curvature.- 9.3.3 Displacement by the Statistical Theory.- 9.3.4 Displacement Grids for Inclined Measures.- 9.4 Calculating Displacement from Tilt.- 9.5 Methods Employing Theoretical Models.- 9.5.1 The Stochastic Model.- 9.5.2 The Elastic Model.- 9.5.3 The Plastic Model.- 9.6 Displacement as Observed on Strata Models.- 9.7 The Graphical Method of the U.K. National Coal Board.- 10. The Time Factor.- 10.1 Significance of the Time Factor.- 10.2 Analysis of Ground Movement over Time.- 10.2.1 The Curve of a Surface Point's Subsidence over Time.- 10.2.1.1 Examples from Longwall Coal-mining.- 10.2.1.2 Influence of the Rock's Mechanical Properties on Subsidence over Time in Room-and-Pillar Working.- 10.2.1.3 Determination of the Time Factor in Salt-mining.- 10.2.2 The Dynamic Trough Profile.- 10.2.3 Dynamic Displacement and Linear Change.- 10.3 The Calculation of Ground Movement over Time.- 10.3.1 The Strip Method with z = 1.- 10.3.2 The Time Factor zt for the Unit Area.- 10.3.3 The Method with Differential Extraction Strips.- 10.3.4 The Influence-related Time Factor ze.- 10.3.5 The Calculation of Static Delayed Subsidence over a Chamber-and-Pillar Working.- 11. Impact of Ground Deformation on Structures.- 11.1 Types of Stress on Structures.- 11.2 Stress/Strain Behaviour of Soils.- 11.3 Earth Pressure on a Foundation Sidewall.- 11.4 Friction Forces Acting on the Structure.- 11.5 Changes in Base Pressure as a Result of Ground Curvature.- 11.6 Time-dependence in the Transmission of Forces.- 12. Mining Damage Above Ground.- 12.1 Types of Damage.- 12.2 Mining Damage to Buildings and Fittings.- 12.2.1 Structural Dislocation and Expansion Cracks.- 12.2.2 Bending Cracks.- 12.2.3 Alternations in Stress.- 12.3 Mining Damage to Industrial Installations.- 12.4 Damage to Communications and Public Utilities Installations.- 12.4.1 Railway Tracks.- 12.4.2 Roads and Bridges.- 12.4.3 Cables and Pipes.- 12.4.4 Canals and Locks.- 12.5 Ground-water Damage from Mining.- 12.6 Settlement Damage Ahead of an Opencast Face.- 12.7 Surface Cave-ins over Abandoned Workings.- 12.8 Pseudo Mining Damage.- 12.8.1 Natural and Artificially Induced Damage to Structures.- 12.8.2 Frequency of Structurally Induced Damage.- 13. The Law Governing Mining Damage.- 13.1 Historical Background.- 13.2 The Legal Relationship Between Mining and Land-Ownership.- 13.2.1 The Law on Mining Damage.- 13.2.2 The Priority Rights of Communications Installations.- 13.2.3 Compensation for Subsidence Damage.- 13.3 The Calculation of Diminished Value.- 13.3.1 Tilt as a Basis of Measurement.- 13.3.2 Determining a Building's Value.- 13.3.3 Reduction in Value for Landed Property.- 13.4 Sharing the Costs for Damage from Two or More Mines.- 13.5 Contingency Funds for Future Mining Damage.- 14. Measures to Reduce Mining Damage.- 14.1 Types of Preventive Measure.- 14.2 Layout Planning Having Regard to Mining Damage.- 14.2.1 Static Measures.- 14.2.2 Dynamic Measures.- 14.2.3 Some Examples of Mining Procedures to Minimize Damage.- 14.3 Structural Precautions.- 14.3.1 Total and Partial Precautions.- 14.3.2 Some Examples of Structural Precautions.- 14.3.2.1 Total Precautions.- 14.3.2.2 Partial Precautions.- 14.3.2.3 Foundation-slab.- 14.3.3 The Protection of Communications Installations and Public Utilities.- 14.4 Regional Planning.- Outlook.- Appendix I Building Standards.- 1. Mining and the Building Ground.- 2. Load Assumptions.- 3. Degree of Mining-damage Precautions.- 4. General Considerations for the Positioning and Design of Structures.- 5. Special Construction for Stage 1 Precautions.- 6. Special Standards for Structures in Stage 2 Precautions.- 7. Special Standards for Structures in Stage 3 Precautions.- 8. Acceptable Stresses, Allowing for the Effects of Mining.- Appendix II Calculation of Ground Movement by the Computer System of Ruhrkohle AG.- Appendix III Classification of Interim Ground Movement in Terms of Time t, Influence Factor e and Extraction Stage r.- Appendix IV Determination of the Time Factor in Mining with Yielding, Permanent Pillars.- Appendix V Examples of Mining Damage.- References.- Note on the SI Units Used.- List of Symbols.