Stability Analysis And Control Scheme Of Rock Slope In Sanyou Mining Area Using The PFC^2D Software

With the massive construction of mine open pits in China,the analysis of the mining pit slopes stability and the control of their instability are increasingly urgent.In this paper,the bedding rock slope in Sanyou limestone mining area in HeBei Province was taken as the research object.Based on the particle flow method,the influence of different joint development characteristics on the rock slope failure mode was analyzed,the slope movement process and failure mechanism were investigated.Through numerical simulation analysis,reinforcement results of slope was analyzed.The main research-and results of the study were as follows:?1?Field geological survey of the research object was conducted to fully investigate the natural geographical environment,geological structure,and other geological conditions of the area.The stability analysis of the slope was carried out using the equator projection method and the Sarma limit equilibrium method.The slope was considered to be in a understable state,and weak interlayers and large-scale joints existed.Further affected by the blasting vibration load and other factors,instable failure occurred.?2?Based on PFC^2D software,using a smooth joint model via weakening the bond strength of the joints in the rock slope,the effect of the weak structural plane of jointed rock slope to the stability was analyzed.The influence of the joint dip angle,penetration degree,spacing,rock bridge dip angle,slope angle,and rock layer dip angle on slope stability and failure mode were analyzed.?3?Through uniaxial compression test,the whole rock parameters of the slope were calibrated,and the joint mechanical parameters were calibrated by the joint plane direct shear test.Based on the PFC^2D software,the rock slope model with joint fracture network was established.The particle displacement,movement speed and crack number in the model were observed;the stress,contact force chain,porosity,and average coordination in the circle at different positions were measured,the failure process and failure mechanism of rock slope were simulated and studied.The results showed that the deformation of argillaceous limestone was serious,the maximum movement displacement and velocity of particles were 12.3m and 5.58m/s,respectively,and the maximum number of cracks was 9425.?4?Based on the field investigation and stability analysis,prestressed anchor cables was designed to strengthen the slope.The anchor angle was 200 and the anchor spacing was 2.5m.32 rows of prestressed anchor cables were arranged with 1 anchor steel strand,and the anchorage section was 6m long.?5?Finally,slope reinforced by prestressed anchor cables support was simulated by PFC^2D software.The displacement,velocity and the number of cracks produced by the particles of argillaceous limestone were obviously reduced after the reinforcement,maintaining a stable state,which showed an obvious improvement on the slope stability by prestressed anchor cables support.