PRACTICAL ROCK MECHANICS
CONTENTS 1 INTRODUCTION TO ROCK MECHANICS INTRODUCTION DIFFERENTIATING BETWEEN SOIL AND ROCK MECHANICS OF FAILURE CLASSIFICATION OF INTACT ROCK COMPRESSIVE STRENGTH OF WEAK ROCK ORIGINS OF SHEAR STRENGTH IN INTACT ROCK SHEAR STRENGTH PARAMETERS FOR THE SAMPLE IN FIGURE 1 3 STABILITY OF A CUT SLOPE IN WEAK ROCK DISCONTINUITIES IN ROCK MASSES INTRODUCTION AND RELATIONSHIP TO GEOLOGICAL HISTORY FRACTURE DEVELOPMENT JOINTS FAULTS 1 10 THE IMPORTANCE OF DISCONTINUITIES TO STABILITY 1 11 EARLY LESSONS AND THE RELEVANCE OF ROCK MECHANICS 1 12 APPLICATION OF ROCK MECHANICS 1 13 HISTORY OF THE SUBJECT AREA 1 14 ROCK MECHANICS AS A SCIENTIFIC DISCIPLINE 1 15 LOAD CHANGES 2 FUNDAMENTAL MECHANICS DEFINITIONS FORCE AND LOAD STRESS STRESS TRANSFORMATION MOHR CIRCLE REPRESENTATION OF STRESS STATE STRESS CONCENTRATION IN UNDERGROUND OPENINGS STRESSES BELOW FOUNDATIONS EFFECTIVE STRESS ROCK DEFORMATION AND BEHAVIOUR ELASTIC BEHAVIOUR AND YOUNG’S MODULUS ROCK BEHAVIOUR BRITTLE FRACTURE AND GRIFFITH CRACK THEORY FAILURE OF ROCK PLASTICITY POISSON’S RATIO DIRECT SHEAR SIMPLE SHEAR AND ASSOCIATED ROCK STRUCTURES SURFACE FEATURES ON ROCK FRACTURES 2 10 CONCLUSIONS TO THIS SECTION 3 GEOLOGICAL PROCESSES AND THE NATURE OF ROCK MASSES EARTH STRESSES PLATE TECTONICS EARTH STRESSES: PREDICTION, MEASUREMENT AND SIGNIFICANCE TO ENGINEERING PROJECTS MEASUREMENT OF STRESS SIGNIFICANCE OF FAULTS TO GROUND ENGINEERING GENERAL NORMAL FAULTS THRUST FAULTING REVERSE FAULTS AND INVERSION TECTONICS STRIKE-SLIP FAULTS FAULT ROCKS EARTHQUAKE OCCURRENCE AND PREDICTION FOLDING ROCK TEXTURES, FABRICS AND EFFECT ON PROPERTIES COOLING OF IGNEOUS ROCK SEDIMENTARY ROCK SANDSTONE MUDSTONE LIMESTONE METAMORPHIC ROCK HYDROTHERMAL ALTERATION WEATHERING DISINTEGRATION MASS WEATHERING FEATURES NEED FOR A CHANGE OF APPROACH AND INCREASED GEOLOGICAL INPUT IN CHARACTERISING FRACTURE NETWORKS STARTING POINT FOR DEALING WITH ROCK DISCONTINUITIES PRIMARY JOINTS COOLING (EXTRUSIVE AND SHALLOW INTRUSIVE) COOLING AND EMPLACEMENT JOINTS (PLUTONIC) SEDIMENTARY SECONDARY, TECTONIC JOINTS REGIONAL JOINTS DEVELOPED AS TENSILE FRACTURES HYBRID JOINTS CLEAVAGE TERTIARY JOINTS JOINT DEVELOPMENT IN GEOLOGICAL AND ENGINEERING TIME SHAPE AND EXTENT OF JOINTS MAJOR GEOLOGICAL STRUCTURES EVIDENCE FROM THE PAST EVIDENCE IN THE PRESENT SLOW PROCESSES CLIMATIC CHANGE FASTER CHANGES RAPID EVENTS RAPID NATURAL EVENTS REFLECTIONS 4 HYDROGEOLOGY OF ROCK MASSES FUNDAMENTAL CONCEPTS AND DEFINITIONS POROSITY HYDRAULIC CONDUCTIVITY AND PERMEABILITY MEASURING HYDRAULIC CONDUCTIVITY DIFFICULTIES WATER TESTS IN BOREHOLES LUGEON TESTING PUMPING TESTS TYPICAL PARAMETERS UNCONFINED AND CONFINED AQUIFERS AND STORAGE UNCONFINED CONDITIONS CONFINED CONDITIONS COMPARTMENTALISATION, AQUICLUDES AND AQUITARDS FLOW PATHS FLOW PATHS IN ROCK (UNWEATHERED) PREFERENTIAL FLOW PATHS IN WEATHERED ROCK ESTABLISHING HYDROGEOLOGICAL CONDITIONS IN WEATHERED ROCK PROFILES CHARACTERISATION AND PREDICTION OF HYDROGEOLOGICAL CONDITIONS FOR PROJECTS SLOPES UNDERGROUND OPENINGS SETTING LIMITS FOR INFLOW PREDICTING INFLOW INTO AN UNDERGROUND OPENING EXPERIENCE OF INFLOW MINING NUCLEAR WASTE REPOSITORIES OIL AND GAS DUAL POROSITY AND WELL TESTING 4 10 GROUTING 4 10 1 PURPOSE OF GROUTING 4 10 2 OPTIONS AND METHODS 4 11 HYDROGEOLOGICAL MODELLING 4 11 1 MODELLING GEOLOGY AS ISOTROPIC 4 11 2 ANISOTROPIC FLOW MODELS 5 CHARACTERISING ROCK FOR ENGINEERING PURPOSES INITIAL STAGES OF SITE INVESTIGATION FIELD MAPPING TRIAL EXCAVATIONS DISCONTINUITY SURVEYS REMOTE MEASUREMENT INTERPRETATION ROSE DIAGRAMS STEREOGRAPHIC INTERPRETATION STEREONETS PLOTTING DATA STEP 1: PLOT A PLANE STAGE 2: PLOTTING A SECOND PLANE AND MEASURING THE INTERSECTING WEDGE PLOTTING LARGE AMOUNTS OF DATA 5 10 ROUGHNESS MEASUREMENT 5 11 GROUND INVESTIGATION TECHNIQUES 5 11 1 INTRODUCTION 5 11 1 1 GEOPHYSICS 5 11 1 2 ROCK DRILLING 5 11 2 SAMPLING AND STORAGE 5 12 DESCRIPTION AND CLASSIFICATION OF ROCKS 5 12 1 INTRODUCTION 5 12 2 ORDER OF DESCRIPTION 5 12 3 STRENGTH 5 12 4 JOINTS AND DISCONTINUITIES 5 12 5 ROCK QUALITY DESIGNATION 5 12 5 1 RQD IN THREE DIMENSIONS 5 13 ROCK MATERIAL AND MASS CLASSIFICATION 5 13 1 INTRODUCTION 5 13 2 WEATHERING CLASSIFICATION 5 13 2 1 MATERIAL-WEATHERING CLASSIFICATIONS 5 13 2 2 MASS WEATHERING CLASSIFICATIONS 5 13 3 OTHER ROCK MASS CLASSIFICATIONS 5 13 3 1 INTRODUCTION 5 13 3 2 ROCK MASS RATING 5 13 3 3 Q SYSTEM 5 13 3 4 RMI 5 13 3 5 GEOLOGICAL STRENGTH INDEX 5 13 3 6 APPLICATION OF GSI 5 14 INTERPRETING GROUND CONDITIONS AND REPORTING 5 14 1 DESIGN INTERPRETATION OF GROUND CONDITIONS 5 14 2 FRACTURE NETWORK MODELLING 5 15 CONTRACTS FOR CONSTRUCTION 5 15 1 INTRODUCTION 5 15 2 UNEXPECTED GROUND CONDITIONS 5 15 3 GEOTECHNICAL BASELINE REPORTS 5 15 3 1 INTRODUCTION 5 15 3 2 CONTENTS OF A BASELINE REPORT 5 15 3 3 OTHER CONSIDERATIONS 5 16 INSTRUMENTATION AND MONITORING 5 16 1 WATER PRESSURE 5 16 2 DISPLACEMENT MEASUREMENT 5 16 3 LOAD CELLS 6 PROPERTIES AND PARAMETERS FOR DESIGN SAMPLING ROLE OF INDEX TESTING BASIC CHARACTERISATION SUITABILITY OF AGGREGATES AGE DETERMINATION ABRASIVITY DURABILITY ROCK STRENGTH AND ITS MEASUREMENT TENSILE STRENGTH COMPRESSIVE STRENGTH UNIAXIAL TEST POINT LOAD TEST SCHMIDT HAMMER SHORE SCLEROSCOPE ROCK STRENGTH AT THE MASS SCALE ROCK DEFORMABILITY SMALL SCALE MASS SCALE PREDICTION FROM GSI ROCK SHEAR STRENGTH AT MASS SCALE CLASSES OF PROBLEM CLASS 1: ISOTROPIC MASSES DIRECT SHEAR TESTING OF INTACT MATERIAL TRIAXIAL TESTING CLASS 2: SHEAR STRENGTH OF ROCK DISCONTINUITIES OPTIONS FOR ASSESSING SHEAR STRENGTH OF ROCK DISCONTINUITIES THE TESTING AND ANALYTICAL APPROACH BASIC FRICTION DIRECT SHEAR TESTING OF ROCK DISCONTINUITIES ASSESSING SHEAR STRENGTH AT THE FIELD SCALE PERSISTENCE AND ROCK BRIDGES CLASS 3: GENERALISED FAILURE SURFACE THROUGH FRACTURED ROCK HOEK–BROWN CRITERION CONCLUSIONS OVER APPLICABILITY OF GSI AND OTHER CLASSIFICATIONS HYDRAULIC CONDUCTIVITY AND RELATED PARAMETERS 7 FOUNDATIONS ON ROCK DESIGN OF SHALLOW FOUNDATIONS BUILDING REGULATIONS/EMPIRICAL APPROACHES SETTLEMENT OF SURFACE FOUNDATIONS ON ROCK RATIONAL DESIGN CALCULATION OF ALLOWABLE BEARING PRESSURE DIFFICULT SITES FOUNDATIONS ON VARIABLE AND COMPLEX ROCKS DISSOLUTION, PIPING AND UNDERGROUND OPENINGS INCORRECT GROUND MODEL PRE-EXISTING GEOLOGICAL MECHANISM DEEP FOUNDATIONS DRIVEN PILES TO ROCK BORED PILES TO ROCK SKIN FRICTION END BEARING EXAMPLES CASE EXAMPLE: THE IZMIT BAY CROSSING: ROCK ENGINEERING FOR THE ANCHORAGE OF A MAJOR SUSPENSION BRIDGE DESIGN CONCEPT SEISMIC ISSUES ROCK ENGINEERING FOR THE NORTH ANCHORAGE PRELIMINARY GROUND MODEL STAGE 2 INVESTIGATIONS STAGE 3 INVESTIGATIONS CONCLUSIONS SITE FORMATION 8 ROCK SLOPES CIVIL ENGINEERING ANALYSIS OF SLOPES IN ROCK THAT CAN BE TREATED AS ISOTROPIC/HOMOGENEOUS ANALYSIS OF SLOPES IN STRONGER ROCK PLANAR AND WEDGE FAILURE ANALYSIS USING STEREOGRAPHIC PROJECTIONS SUMMARY REGARDING STEREOGRAPHIC METHODS DETAILED ANALYSIS FOR PLANAR FAILURE GEOLOGICAL MODEL DESIGN CONDITIONS AND PARAMETERS FACTOR OF SAFETY ANALYSIS OF BLOCK A ANALYSIS OF BLOCK B DETAILED ANALYSIS OF WEDGE FAILURE TOPPLING 8 1 10 ROCKFALL 8 1 10 1 INTRODUCTION 8 1 10 2 ROCKFALL HAZARD ASSESSMENT 8 1 10 3 MANAGEMENT OF RISK 8 1 10 4 HAZARD RATING SYSTEMS DESIGN OF ENGINEERING WORKS ASSESSING NEED FOR PREVENTIVE ENGINEERING MEASURES GENERAL CONSIDERATIONS ENGINEERING OPTIONS SURFACE TREATMENT MESH DRAPES FENCES, CATCH-NETS AND BARRIERS DRAINAGE SURFACE WORKS DRAINAGE OF SUB-SURFACE WATER REINFORCEMENT PASSIVE ANCHORAGES ACTIVE ANCHORAGES BUTTRESSING AND LARGER RETAINING STRUCTURES SLOPE FORMATION SAFETY AND CONTRACTUAL ISSUES CONTRACTUAL AND SUPERVISION CONSIDERATIONS METHODS FOR BREAKAGE AND REMOVAL OF ROCKS FLY-ROCK HAZARDS QUARRYING OPEN-PIT SLOPES 9 UNDERGROUND EXCAVATIONS DIFFERENCE BETWEEN TUNNELS AND CAVERNS STABILITY CATEGORIES FOR UNDERGROUND EXCAVATIONS CATEGORY A: STABLE CATEGORY B: DEFORMING CATEGORY C: SEVERE INSTABILITY OTHER ISSUES OVERSTRESSING INVESTIGATION COST OF INVESTIGATION INVESTIGATION FOR TUNNELS: GENERAL EXAMPLE OF GEOLOGICAL PREDICTIONS FOR A LONG TUNNEL DIRECTIONAL DRILLING PILOT TUNNELS GEOPHYSICS INVESTIGATIONS FOR SUB-SEA TUNNELS CHANNEL TUNNEL THE SSDS TUNNELS IN HONG KONG (LATER RENAMED HATS STAGE 1) GEOTECHNICAL BASELINES AND RISK REGISTERS GEOTECHNICAL BASELINES FOR TUNNELS RISK REGISTERS INVESTIGATION FOR CAVERNS DESIGN DESIGN OF TUNNELS OPTIONS FOR TUNNELLING IMPORTANCE OF PORTALS WATER INFLOWS SUPPORT BASED ON RMCS USE OF CLASSIFICATION SYSTEMS FOR ‘PRECEDENT DESIGN’ SUPPORT IN SQUEEZING GROUND SUPPORT MEASURES AND INTERNAL LINERS INCLUDING PRESSURE TUNNELS TUNNELS DESIGNED FOR TBM EXCAVATION TUNNELLING IN WEATHERED ROCK DESIGN OF CAVERNS CAVERN SHAPE CASE EXAMPLE: PRELIMINARY DESIGN FOR LARGE-SPAN UNDERGROUND STATION ROCK LOAD CONCLUSIONS REGARDING TAEGU CALCULATION OF ROCK LOAD NUMERICAL MODELLING CONSTRUCTION CONSTRUCTION OF TUNNELS BY DRILL AND BLAST OR ROADHEADER THE OBSERVATIONAL METHOD MAPPING MONITORING INVESTIGATING IN FRONT OF THE TUNNEL DURING CONSTRUCTION INSTALLATION OF SUPPORT SUPPORT IN ADVANCE OF THE TUNNEL REINFORCING SPILES OTHER METHODS TBM EXCAVATION CAVERN CONSTRUCTION