关键词: 应力解除法, 三维地应力测量, 应力分布特征, 滥泥坪铜矿, 巷道稳定性, 数值模拟

Abstract:

The in-situ stress is the fundamental force causing damage and deformation of underground rock engineering.With the continuous increase of the mining depth，the ground pressure disaster of the mining area has gradually increased under the action of deep high ground stress.A large number of untreated goaf have been formed in the exploration and mining operations of the old and new areas of the Lanniping copper mine. Due to the influence of ground pressure，a number of collapse pits have been formed on the surface.In order to continue the safe and reasonable production work in the mining area，it is necessary to accurately measure the distribution of ground stress in the area and to optimize the layout of the roadway.The three-dimensional in-situ stress test was carried out on the three middle sections of the deep Lanniping copper mine by the stress relief method，9 sets of testing data in vertical direction are obtained.Meanwhile，the confining pressure rate test was carried out on the core sample，and the working state of 12 stress sheets was determined，and the distribution characteristics of the three-dimensional stress field were analyzed.The measurement results show that maximum principal stress，intermediate principal stress and minimum principal stress show an increasing trend with the increases of depth.The maximum principal stress values of the three measuring points in this test result are all high，the minimum value is 2 350 m，which is 28.62 MPa，and the maximum value is 1 900 m，about 43.1 MPa.According to domestic and international experience，the original rock stress field in the Lanniping belongs to the high geostress state.Combined with the layout of the stope and the specific mining method，the corresponding ground pressure testing measures and reasonable support methods should be adopted to ensure the safe mining of the mine.The original rock stress field is dominated by horizontal tectonic stress.The overall performance is NNW-SSW. According to the maximum shear stress theory，when the vertical stress at the top of the roadway and the vertical stress at the sidewall of the roadway are greatly different，the roadway layout should follow the formula of equal-stress axial ratio （i.e.，roadway gang width/roadway gang height = vertical stress at the sidewall of the roadway/vertical stress at the top of roadway），and then the roadway should be most stable.With the measurement results applied to maximum shear stress theory，the roadway layout is optimized，and a three-dimensional geological model is built within which the stability of the roadway is analyzed.Through analysis and comparison，it is found that the stress，displacement characteristics and plastic zone distribution of the surrounding rock in the rearranged roadway are superior to the original roadway.Therefore，the section size and stress distribution of the roadway should be considered to determine the optimal arrangement of the roadway in the actual engineering.The measurement results have important guiding significance for mine support design and safe production.

Key words: stress relief method, 3D ground stress measurement, stress distribution characteristics, Lanniping copper mine, drift stability, numerical calculation