RESEARCH ON LIMIT ANALYSIS UPPER BOUND METHOD FOR STABILITY EVALUATION OF ANCHORED ROCK SLOPE
加锚岩质边坡稳定性评价的极限分析上限法研究

A new computational model for stability analysis of anchored rock slope is presented based on the theory of limit analysis upper bound method after taking the supporting effect of rock-bolts,the influences of seismic force and fissure water pressure into consideration.A kinematically admissible velocity field for the model can be obtained when the rock slope is divided into different sliding block elements along the slip surface and structural planes.According to the conditions of associated flow rule and displacement compatibility,the move of the two adjoining elements can not cause overlap or indentation.Moreover,the mathematical formulas of strain velocity field can be derived.By using the model,not only the external power done by dead weight,seismic force,fissure water pressure and anchorage force but also the internal energy dissipation produced in the slip surface and structural planes can be totally calculated.According to the condition of virtual work rate equation in limit state,the formula of stability factor for limit analysis upper bound method can be deduced.In order to evaluate the validity of the proposed method,a typical case is calculated.Results show that the stability factor of rock slope will decrease when the fissure water pressure and seismic force are considered.However,the safety factor of rock slope stability will increase after the slope is reinforced.