Stability evaluation of auxiliary shaft based on numerical simulation and deformation monitoring
The auxiliary shaft is generally arranged not far from the lower wall of the orebody when the steeply inclined orebody is mined,so that the mining of the orebody near the auxiliary shaft may induce the stress concentration or damage of the auxiliary shaft wall.In the past,the Acoustic Emission(AE)technique was used to monitor and evaluate the stability of the surrounding rock of the auxiliary shaft,but often because the monitoring point arrangement is not reasonable,causes the long-term monitoring data to have no change.Therefore,taking Sanxin of Hubei province as an example,FLAC3D is used to simulate the change of stress and displacement in the surrounding rock of the auxiliary shaft caused by stope layout along strike or vertical strike,and the strain and displacement meter is adopted to monitor the stress and displacement of the shaft wall.The research shows that the stope arrangement along the strike of the ore body is extremely unfavorable to the stability of the surrounding rock,the hanging bottom pillar,and the side wall of the mining section.The stope arrangement along the strike or the vertical strike with a large width does not cause obvious displacement of the surface and the side wall near the mining elevation section but causes stress concentration in the side wall about 250m below the wellhead due to deformation.As the tensile stress of the auxiliary shaft increases with increasing stope width,it has little relation with the increase of mining depth and the stope must be vertically arranged and the stope width must be reduced.After adopting the two-step mining of up-bound filling with a 4 m × 4 m approach,the variation of other monitoring values can be almost neglected except for two consecutive vertical displacements and stress differences exceeding 1.2 mm and 1.4 MPa caused by occasional fast driving near the rock and soil interface.The subsidence observation of surface bedrock indicates that the variation of subsidence value at each point is generally less than 3 mm.
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万方数据
维普
