Metodos de soporte para mineria subterranea

SUPPORT OF UNDERGROUND EXCAVATIONS IN HARD ROCK

E. Hoek, P.K. Kaiser and W.F. Bawden

Funding by Mining Research Directorate and Universities Research Incentive Fund

Table of contents

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Table of Contents

Preface............................................................................................. vForeword......................................................................................... vii 1. An overview of rock support design........................................... 1.1 Introduction.................................................................. 1.2 Stages in mine development........................................... 1.2.1 Exploration and preliminary design................... 1.2.2 Mine design......................................................1.2.3 Early years of mining........................................ 1.2.4 Later years of mining........................................ 1.3 Support design.............................................................. 2. Assessing acceptable risks in design............................................ 2.1 Introduction.................................................................. 2.2 Factor ofsafety............................................................. 2.3 Sensitivity studies.......................................................... 2.4 The application of probability to design......................... 2.5 Probability of failure..................................................... 2.6 Problems to which probability cannot be applied............ 3. Evaluation of engineering geologydata...................................... 3.1 Introduction.................................................................. 3.2 Engineering geological data collection........................... 3.3 Structural geological terms............................................ 3.4 Structural geological data collection.............................. 3.5 Structural geological datapresentation.......................... 3.6 Geological data analysis................................................ 4. Rock mass classification.............................................................. 4.1 Introduction.................................................................. 4.2 Engineering rock mass classification.............................. 4.2.1 Terzaghi's rock mass classification.....................4.2.2 Classifications involving stand-up time............... 4.2.3 Rock quality designation index (RQD)................ 4.2.4 Rock structure rating (RSR)............................... 4.3 Geomechanics classification.......................................... 4.4 Modifications to RMR for mining................................. 4.5 Rock tunnelling quality index, Q.................................... 4.6Using rock mass classification systems.......................... 4.7 Estimation of in situ deformation modulus..................... 1 1 1 3 3 4 7 7 8 8 9 10 10 16 18 20 20 20 21 22 23 24 27 27 27 28 29 30 31 34 38 39 45 47

5. Shear strength of discontinuities................................................. 51 5.1 Introduction..................................................................51 5.2 Shear strength of planar surfaces................................... 51

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Support of underground excavations in hard rock 5.3 Shear strength of rough surfaces.................................... 5.3.1 Field estimates of JRC....................................... 5.3.2 Field estimates of JCS....................................... 5.3.3 Influence of scale on JRC andJCS..................... 5.4 Shear strength of filled discontinuities........................... 5.5 Influence of water pressure............................................ 5.6 Instantaneous cohesion and friction............................... 6. Analysis of structurally controlled instability............................. 6.1 Introduction.................................................................. 6.2...