Study On The Law Of Movement And Failure Of Rock Strata Caused By Open Pit To Underground Mining

The mining area to be study on in this paper will transfer the method of mining from open pit mining to underground mining. And with the advance of the open-pit final slope and underground mining, the slope will absolutely slide, which will have great impact on the surrounding buildings and infrastructure.Based on this background, we prospect the Yanqianshan mining area and monitor the deformation and failure of slope in prospecting area during mining process. Meanwhile we analysis the deformation rules and the failure mechanism of slope rock movement at different mining stages by engineering geology analysis principle. Then based on three-dimensional discrete element method, we study and improve the modeling method of Equivalent Jointed Rock-mass Model(EJRM), the method of how to determine the mechanical parameters about EJRM, the simulating method of large displacement motion and failure process, and the simulating method of mining process. As a consequence, we solve the problem of how to simulate the non-continuum and large displacement motion of EJRM. And we obtain the three dimensional numerical simulation prediction method of rock strata and surface movement during open pit to underground mining.The main work of this thesis includes the following 4 parts:(1) We regularly observed the slope deformation and failure status in the scope of monitoring mining. Along with the advance of mining progress, the present situation of slope failure in different mining phases is analyzed.(2) The equivalent method of the rock mass structure is studied. And the equivalent joint rock mass model is established by using the three-dimensional discrete element numerical simulation software 3DEC;(3) The joint mechanical parameters of the EJRM is obtained by using the method of orthogonal experiment connected with numerical simulation. Then, by comparing the slope failure situation caused by the simulation with the actual mining activities, the joint mechanics parameters are verified;(4) According to the actual conditions, we achieve the simulation of large displacement motion during the open pit to underground mining. And we obtain the rock strata and surface movement damage rules and slope rock mass deformation and failure mechanism. Then we get the three dimensional numerical simulation and prediction method of rock strata and surface movement law.