Law And Mechanism Of Shaft Deformation And Failure Under The Dual Influence Of Mining And Fault

As shallow resources are increasingly depleted,filling mining of deep orebodies has become the mainstream.However,facing more complex engineering geological conditions,higher geostress environments,and softer and more fractured rock conditions,the stability problems of surrounding rock structures and constructed facilities caused by filling mining still exist,especially under the conditions of large-scale mining of the deep and thick orebodies.This paper conducts systematic research on the deformation and failure of the NO.14 ventilation shafts under the influence of thick orebody mining in the Jinchuan Mine,explored the law and mechanism of shaft deformation and failure under the dual influence of mining and fault,then proposed prevention and control measures.The main research contents are as follows:(1)The research and analysis of engineering geological conditions,mining technology and current situation of Jinchuan mining area,as well as the damage and repair situation of the air shaft in the early stage were carried out.The detection and analysis of the shaft which occurred deformation and failure again were carried out to identify the deformation and failure area,failure degree and failure characteristics of the shaft.And the mechanical process of the shaft developing from a single thrust shear plane to a "two-way step" failure section was analyzed.The "double shear" mechanism of shaft failure is preliminarily revealed.(2)A comprehensive online monitoring system for the movement of fault area in the NO.14 ventilation shaft and the evolution of displacement and stress in deep surrounding rock is constructed.The characteristic parameters of fault activation were put forward,and the characteristics,rules and influencing factors of fault activation were proved.The migration behavior and law of deep surrounding rock under the influence of mining are expounded,and the evidence chain of disaster process caused by the shaft instability is comprehensively analyzed and improved.(3)The physical simulation tests of surrounding rock migration and fault activation under mining action were carried out.Based on the monitoring results of embedded microsensors,the evolution law of surrounding rock internal stress under continuous mining was analyzed.The DIC system was used to conduct realtime monitoring and analysis of the surface strain of the test model,which intuitively revealed the evolution law of surrounding rock strain under the influence of mining and the influence process of wellbore stability.Based on the mechanical laws of similar simulation tests,a mechanical model of fault activation considering the influence of mining was constructed,and the trigger criterion of fault activation was proposed.(4)The numerical simulation of fault activation and shaft instability under the influence of mining is carried out.The evolution process of ground pressure activity of surrounding rock under historical mining conditions is analyzed,and the law of surface settlement and shaft deformation under the influence of mining is revealed.Combined with the production planning of the No.2 mining area,the influences of mining sequence,mining intensity,backfill strength and filling and topping rate on fault activation and shaft instability under continuous mining disturbance are explored.(5)The disaster chain theory is introduced to analyze the influencing factors of wind shaft instability in Jinchuan No.2 mining area,and the chain model of ventilation shaft disaster caused by large area continuous filling mining disturbance is established.Based on the current situation of shaft deformation and failure and the demand of production service,the suggestions of mining and filling of the upper lean ore in No.2 mining area and the technical measures of strengthening the shaft failure area by stage and time are put forward.