Upper Limit Analysis Of Three-dimensional Reinforced Slope Stability Under Complex Working Conditions

Reinforcement materials such as geosynthetics can significantly improve the stability of geotechnical structures such as slopes,which makes reinforcement materials are increasingly used in practical engineering in recent years.Based on the plasticity theorem of limit analysis,this paper analyzes the stability of three-dimensional(3D)reinforced slopes under various common external forces,which mainly include seismic force and pore-water pressure,under different assumption methods,the upper solutions of the 3D reinforced slope stability under different working conditions were optimized,then the stability variation rules of 3D reinforced slopes under the action of seismic force,pore water pressure and matric suction were further explored.Based on these research results,the relevant suggestions are put forward for engineering practice.The main research content of this paper are listed below:(1)Based on the upper bound theorem of limit analysis,the stability of 3D reinforced slope under the influence of horizontal and vertical seismic forces in uniform and triangular reinforced mode were investigated.First,the horizontal and vertical seismic forces are expressed as the external work rate equations by the pseudo-static method,on the basis of the power balance equation of the whole failure mechanism,the explicit analytical expression for the critical reinforcement strength required of 3D reinforced slope was derived.Then,the influence of different parameters on the 3D solutions of critical reinforcement strength are discussed,and corresponding parameter analysis is performed.(2)The stability analysis of the 3D reinforced slope subjected to pore-water pressure is performed.According to the plastic theory,the external force power of soil self-weight and pore-water pressure,the internal energy dissipation rate of reinforcement are calculated,and then the explicit expressions of the critical reinforcement strength under different reinforcement patterns are derived by using the power balance equation.The effects of the ratio of slope width to height,the pore-water pressure coefficient and the soil friction angle are investigated.Finally,two design reference tables are listed to provide useful reference for the design of engineering practice.(3)The pseudo-dynamic method is applied to characterize the time-varying effects of seismic force,and the seismic dynamic stability of 3D reinforced unsaturated soil slope is performed.The time-varying effect of the seismic force is reflected by considering the period of the seismic wave and the amplification factor of the soil,a linear assumption is made that the matric suction in the unsaturated soil is uniformly distributed along the slope height.According to the working energy balance equation and strength reduction method,the safety factor expressions of 3D reinforced unsaturated soil slope under different reinforcement patterns for different horizontal seismic coefficients and matric suction are derived,and then the influence of various parameters including the horizontal seismic force coefficients,pseudo dynamic parameters and matric suction on the slope stability is analyzed and the corresponding stability chart is drawn.