Research On The Influence Of Repeated Mining On Tunnel Safety And Its Control Measures

The multi-layer thick ore body stratified filling mining has caused many disturbances and damages to the stress distribution of the overlying original rock stratum.At this time,the roadway is excavated in the stratum after multiple additional stress field evolution,and thus in the surrounding rock of the roadway.The attachment stress of the heart is generated and the re-stacking effect is generated with the additional stress field of the mining disturbance,which is fundamentally different from the excavation roadway in the original rock;and there is also the influence of complex engineering geological structure and stratum distribution.These unfavorable factors have caused great difficulties in the tunneling and support of the roadway.Therefore,it is of great practical value to deepen the study of the mechanical characteristics of the excavation of complex rock mass and its deformation and failure law.Based on the mining background of No.2,No.11 and No.12 ore bodies in Macheng Iron Mine,this paper uses numerical simulation and theoretical research to systematically analyze the evolution law of stress field and displacement field of surrounding rock under multiple mining disturbances.,reveal the deformation and failure mechanism of the surrounding rock of the roadway,and use the corresponding safety measures to strengthen the roadway.The main findings are as follows:(1)Based on the design and mining scheme of Macheng Iron Mine,the finite element numerical simulation method is applied to simulate the evolution law of stress field and displacement field of surrounding rock under repeated mining in mining area,and analyze the research of roadway around each layer.The stability of the rock under the disturbance of mining,judging the safety of the roadway,and providing guidance for the support and reinforcement of the roadway.(2)According to the analysis results of the surrounding rock stress field of the roadway,the safety evaluation of the roadway at each position is carried out.The reinforcement scheme of the No.2 ore body and the No.11 and No.12 ore bodies in the dangerous area was optimized,and then the numerical simulation method was used to carry out the inspection.The results met the safety production requirements.(3)By collecting the stress monitoring data on the site,based on the gray theory,the GM(1,1)model for predicting the roadway stress is established,and the optimal modeling dimension of each roadway prediction model is determined and unsafe.The roadway stress in the area is predicted and used as the basis for roadway reinforcement.