STABILITY ANALYSIS OF SLOPE Limit equilibrium Method (LEM) Advantage of LEM Limitation of LEM Numerical modeling Advantage Limitation Software based on Limit equilibrium Method SLIDE (rocscience group) GALENA GEO-SLOPE GEO5 GGU SOILVISION Software based on Numerical modeling PHASES2 PLAXIS FLAC-SLOPE / UDEC / PPF ANSYS FEFLOW GEOSLOPE/SIGMA SOIL-VISION Required input properties Young modulus Poisson ratio Density Failure criterion: M-C H-B Cohesion UCS Friction angle m&s Numerical modeling Type of failure mechanism Physico-mechanical behaviour of slope material Types of analysis Numerical modeling • Continuum modelling FEM, BEM and FDM • Discontinuum modelling DEM, UDEC • Hybrid modelling PPF, What are the conditions of slope in the field Simple slope with single, two or three joints Large number of joint sets present in the slope Heavily jointed rock slope Waste dump / very weak rock / soil Simple slope with single, two or three joints Properties of each Joints strength large number of joint sets present in the slope Properties of each joint set or combined properties Heavily jointed rock Properties of jointed rock mass Waste dump / very weak rock / soil Properties of waste rock Continuum modelling Continuum modeling is best suited for the analysis of slopes that are comprised of massive, intact rock, weak rocks, and soil-like or heavily jointed rock masses. Discontinuum modeling is appropriate for slopes controlled by discontinuity behaviour. Critical Parameters: shear strength of material, constitutive criteria, water condition, insitu stress state Advantages: Allows for material deformation and failure, model complex behaviour, pore pressures, creep deformation and/or dynamic loading can be simulated Limitations: inability to model effects of highly jointed rock Continuum modelling • Typical Input required Moduls of Elasticity Poision ratio Density Shear strength (cohesion and friction angle) Model Behavior Continuum modelling Typical Input required • Moduls of Elasticity for rock and joints • Poision ratio for rock and joints • Density • Shear strength for rock and joints • Joint behaviour • Water pressure • Continuum modelling (water simulation) Pore water pressure Ground water table Infiltration of rain water Discontinuum modelling Discontinuum modeling is appropriate for slopes controlled by discontinuity behaviour Critical Parameters: discontinuity stiffness and shear strength; groundwater characteristics; in situ stress state. Advantages: Allows for block deformation and movement of blocks relative to each other, can modeled with combined material and discontinuity behaviour coupled with hydro - mechanical and dynamic analysis Limitations: need to simulate representative discontinuity geometry (spacing, persistence, etc.); limited data on joint properties available Discontinuum modelling Discontinuum modelling cohesion joint dilation joint friction joint joint normal stiffness joint shear stiffness Hybrid modelling Hybrid codes involve the coupling of these two techniques (i.e. continuum and discontinuum) to maximize their key advantages. Critical Parameters: Combination of input parameters Advantages: Coupled finite-/distinctelement models able to simulate intact fracture propagation and fragmentation of jointed and bedded rock. Limitations: high memory capacity; Important considerations Two-dimensional analysis versus three-dimensional analysis 2D Simulation by Geoslope software based on Finite element method 3D Simulation by Ansys software based on Finite element method Continuum versus discontinum models 2D simulation of bench slope by FLAC based on finite difference method 3D simulation of slope 3DEC software based on discontinum modeling Selecting appropriate zone size Different view discritized view of internal dump slope Boundary conditions Typical recommendations for locations of artificial far-field boundaries in slope stability analyses. Water pressure Simulation of rain water infiltration and generation of water table Excavation sequence Show the sequential excavation Stability / failure indicators Factor of safety Displacement ( x and Y) Shear Strain Yield Points Plastic Points unbalance force/ convergence of solution Velocity Stability / failure indicators Factor of safety C trial trial 1 F trial C arctan 1 F trial tan Stability / failure indicators Displacement ( x and Y) Stability / failure indicators Shear Strain Stability / failure indicators Yield Points Stability / failure indicators Velocity Vector Stability / failure indicators unbalance force/ convergence of solution

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# Numerical Modeling