Study On Destruction Of Surface Borehole For Methane Drainage With Mining Influence

Over burden movement due to coal seam mining will have influence on surface borehole for methane drainage,even severly destruction,and hinder the work of methane drainage in the meantime. This dissertation applies theoretical analysis and numenical simulation to study on destruction of surface borehole based on the industrial trial of Xie Qiao colliery in Huai Nan. Some good conclusions have been got through elementary research and have important reference value to stability of surface borehole.This dissertation mainly carry through four research work. Firstly,stress distribution characteristic of surrounding rock of surface borehole with deep coal seam minng has been got applying relative knowledge of strata movement theory,elasticity and rock mechanics. Plastic area distribution expression around rock mass of borehole has been got too according to mechanics distribution formula on the assumption that borehole has equal pressure on two directions.Secondly,the conditions of cutting and separating between stratas have been got through elementary analysis to law of movement and distortion of overburden. Relative knowledge of theory of thin board bend in elasticity and strata movement with mining is mainly analytic method. Thirdly,law of time and space of movement and distortion of strike and dip of overburden with mining has been studied in numenrical simulation menthod. This study is mainly in order to deeply disclose destruction of surface borehole and offer good support for seleting secure borehole position.Fourthly,some protective measures have been put forward for solvng destruction of surface borehole. There is important guiding significance to site practice.