Introduction

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Transcript Introduction

Introduction:

• • • • Slopes either occur naturally or are engineered by humans.

An understanding of geology, hydrology, and soil properties is central to applying slope stability principles properly.

Analyses must be based upon a model that accurately represents site surface conditions, ground behavior, and applied loads.

Type of Analysis

Aim of slope

• • • • • • Assess the stability of slopes under short-term Assess the possibility of slope failure / satbility Understand failure mechanisms and the influence Enable the redesign of failed slopes and the planning and design The effect of seismic loadings on slopes Safe and economic design of excavations, embankments, earth dams, landfills, and spoil heaps .

FACTORS AFFECTING SLOPE FAILURE

Introduction Geological discontinuities Effect of Water Geotechnical Properties of Material Mining Methods State of stress Geometry slope: Temperature Erosion Seismic effect Vegetation

TYPES OF ROCK SLOPE FAILURE

Introduction Plane failure Wedge Failure: Toppling failure Rockfalls Rotational Failure

Rock Slope Stability Analysis: Limit Equilibrium Method Planar Failure Analysis Sliding analysis of a block Plane failure analysis along a discontinuity Water is filled in discontinuities Tension crack present in the upper slope surface Tension crack present in the slope surface The tension crack is filled with water with upper slope angle Effect of rock bolts Wedge Failure Analysis Analysis of wedge failure considering only frictional resistance Analysis of wedge failure with cohesion and friction angle Toppling Failure Analysis Kinematics of block toppling failure Limit equilibrium analysis for toppling failure Stability analysis of flexural toppling

CIRCULAR FAILURE ANALYSIS

Introduction Stability analysis of slope Stability analysis for Cohesionless Soil Total Stress Analysis (Swedish slip circle method) Ordinary slip circle method Bishop’s Simplified Method of Slices General Method of slices

SLOPE STABILITY ANALYSIS BY NUMERICAL MODELLING

Introduction Continuum modeling Discontinuum Modeling Hybrid approach Important considerations Continuum versus discontinuum models Selecting appropriate zone size Initial conditions

Boundary conditions

Water pressure Excavation sequence Important failure indicators in slope analysis Factor of Safety Unbalanced Force Gridpoint Velocities Plastic Indicators Displacement Failure Surface

STABILITY ANALYSIS IN PRESENCE OF WATER

Introduction Common terms used in simulation of water Important Geotechnical properties related to water Permeability Hydraulic Conductivity Factor affecting soil permeability and hydraulic conductivity Matrix suction Consistency of soil Pore Pressures Infiltration Rainfall Infiltration Model.

Simulation of water

SEISMIC ANALYSIS

Introduction Types of seismic wave Dynamic Soil Properties Field Measurements of Dynamic Modulus Ground Motion Estimates Factors Affecting Ground Motion: Simulation of seismic effect Pseudo-static approach Wedge Method Method of Slices Inertia Slope Stability – Newmark Method

SLOPE STABILIZATION

Introduction Removal And Repair Excavation & repair Catchment & Wire Netting Grading & Serrating Benching Resloping and unloading Lightweight Fill Counterberms Trimming Shear Keys Scaling Drainage and Water Control Surface Drainage Subsurface Drainage

Stabilization Through Support Steel reinforcement Rock anchor Rock Bolts Rock Dowels Soil Nailing Piles Geosynthetic Reinforcement Retaining Walls Gravity Walls Cantilever Retaining Walls Sheet Piling Retaining Walls Anchored retaining wall Gabions Other Methods For Stabilization

Grouting and Shotcrete

Vegetation

SLOPE MONITORING: TECHNIQUES AND INSTRUMENTS Introduction Slope failure mechanism Types of Slope Movement Initial response Regressive and progressive movement Long-term creep Sub-Surface Monitoring Methods Borehole probes Time–domain reflectometry Inclinometers Extensometers

Measurement of water level and pressure Standpipe Piezometer Pneumatic Piezometer Vibrating Wire Piezometer Surface Monitoring Methods Crack Monitors Surveying Photographic Image Analysis Total Station Global positioning system (GPS) Acoustic emission technique Laser image scanning system Slope Stability Radar system Synthetic aperture radar

landslides

Introduction Slope Failure Slumps Rock Falls and Debris Falls Rock and Debris Slides Sediment Flows Solifluction Debris Flows Mudflows Creeps Earthflows Debris Avalanches Historical landslides (wiki ) Major factors affecting landslides

Mine Waste Dump

Introduction Method of Construction in lift section Methods of Stability Calculation Shear Strength of dump material Particle shape, roundness and grain surface texture Effect of moisture condition on shear strength Factors Affecting Dump Stability Dump Configuration Foundation Conditions Dump Material Properties Dumping method Dumping Rate Seismicity and Dynamic Stability Topography Dump drainage

Material properties and testing Bulk Gradation Plasticity of Fines Index Properties and Classification Hydraulic Conductivity Consolidation Strength Mineralogy and Soil Chemistry In Situ Density Compaction

Tailing Dam

Failure Modes in tailing dams Rotational Sliding Foundation Failure Overtopping Erosion Piping Tailings Impoundment Design Mill Location Topography Geology and Ground Water Tailings impoundments Tailings storage facilities Methods for Tailings Disposal Upstream Method Downstream Method Centerline Method

Sensitivity, probability and reliability analysis Sensitivity Analysis Probabilistic Design Methods Reliability Analysis

Classification systems in slope stability analysis

General Slope Mass Rating (SMR) Chinese Slope Mass Rating System (CSMR) Rock slope rating (RSR) Slope stability rating (SSR) classification system Dump mass rating

Introduction of softcomputing approach in slope stability Artificial Neural Network Fuzzy Inference System