Study On The Deformation And Failure Model Of Slope And Its Stability Under The Condition Of Underground Mine Exploitation

Underground mine exploitation can result in the redistribution of stress in rock (soil) slope, so the rock or soil will deform, and even make failure. The failure of slope not only threatens people and their property, but also leads to casualty and economic losses. For early study on this kind of deformation and failure of the slope, scholars usually divide the slope into some levels which make deformation induced by mine exploitation. This kind of study method can not explain completely the deformation and failure induced by exploitation subsidence. Especially, it can not effectively determine landslide scope and feature induced by the deformation of the instable slope, which will influence the stability evaluation of the slope and the pertinence of prevention measures. Above all, it is very significant for the study on the deformation and failure mode, mechanism, as well as stability due to underground mine exploitation.The deformation mode of the slope induced by underground mine exploitation was studied firstly. According to different geology and exploitation conditions, one hundred and eight failure modes of typical rock and soil slope were established. Using modern mathematics theory and coal mining subsidence theory, the different deformation characteristics of the slope were simulated and calculated under the condition of underground mine exploitation. Simulation results showed that the deformation would become intense with slope gradient increasing; The deformation would become weak with deeper exploitation; The deformation would become intense with larger exploitation mining scale (exploitation thickness, exploitation scope).Taking Fengmaoding slope located in Taiyuan Gujiao as a typical engineering example, which is the typical slope with the condition of underground mine exploitation. Based on the deformation feature under the condition of underground mine exploitation and geological environment, combined with factual monitoring data of slope, it was found that the slope deformation was characterized by zonation. Specifically, slope toe showed horizontal displacement-ridge deformation; Slope waist showed horizontal displacement-intense subsidence deformation; And slope top showed horizontal displacement-weak subsidence deformation. Based on the comprehensive analysis on forecasting model of ground surface movement, the deformation mechanism of the slope under the condition of underground mine exploitation was the sequence below:underground exploitation, subsidence deformation on the top of the slope, slope failure, back edge cracking, and front edge extruding and uplifting.Based on these works above all, according to the factual information of the Fengmaoding slope, geological model was established. Combined with the deformation mode of the slope under the condition of exploitation, numerical model was established. And the stress and strain in the slope under the condition of mine exploitation were simulated. Under the condition of ground mine exploitation, geological and numerical models were established respectively with/without fault in the slope. The slope deformation and failure process from simulation results showed that under the condition of underground mine exploitation, the deformation and failure distribution scope and extent of stress and strain in the slope without fault were less than them with fault. In other words, underground goaf was the main factor influencing the stability of slope, and the deformation and failure would become larger with fault in the instable slope.In the end, based on the method of Morgenstern-Price from limited balance theory, using SIGMA/W and SLOPE/W modules, stability of the slope was analyzed and simulated respectively under the condition of nature or heavy rain, with mine exploitation or not. And the resulting factors of stability were gotten under different condition. It was found that the slope was basically stable before mine exploitation, and it would make deformation after mine exploitation under the natural condition. It would become very unstable under the condition of heavy strain.