Analysis on Backfill Mining of 'Under Three' Coal in Zhouyuanshan Mine and Strata Movement Law

摘要

In order to solve the problem of "under three" (under railways, buildings and water bodies) coal pillar mining, analysis on backfill mining and strata movement law is carried on in 24 mining district of Zhouyuanshan coal mine. First of all, according to the engineering geology and strata occurrence condition in 24 mining district of Zhouyuanshan coal mine, FLAC2D software be used to establish a two-dimensional numerical model and to analyze and calculate the full caving method, strip method and backfill method and then gaining that backfill mining method is beneficial to improve the protection level of surface buildings and facilities. Then, using the theory of strata control and method of related mechanics to analyze the strata movement law and strata control principle of backfill mining, considering that supporting role of backfill body is mainly on lateral reinforcement of coal pillar and vertical supporting role of overlying strata, forming a cooperative control system of "bearing strata + coal pillar + backfill body" and deducing the equilibrium equations when it is in steady state. At last, using the numerical analysis method, respectively analyzing the surface subsidence of the corresponding important buildings of the three profiles of C-8 exploration line ,C-6 exploration line and A-A (cross section of the profile of C-8 exploration line) after using backfill coal mining in 24 mining district. The results show that: the surface subsidence and horizontal deformation basically control within 30 mm and the surface deformation curvature of buildings generally in 0.1×10~(-3) /km in 24 mining district of Zhouyuanshan coal mine, which accord with the relevant standards and requirements.