Numerical Simulation Analysis On Mechanized Mining Ground Pressure Apperance Law And Tunnel Supporting Effect

The coal is in major position of one-time energy structure in my country and plays an important role in national economy.Because coal in my country is usually extracted from underground where geology conditions is complex and most tunnels is always affected by mining greatly during service period,maintenance of tunnel in coal and rock is more difficult.As anchor supporting technology applys in coal mine extensively,determination of reasonable anchor supporting parameters becomes a problem that needs people to solve.Shenhua Group Pinggou coal mine gorund extraction is the study background in this peper. According to geology condition ,methords of working-face's arrangement and existing coal extracting technology in Pinggou coal mine ,numerical simulation software FLAC 3D,which is the most popular in the word, is used to simulate and calculate deformation charactoristic of surrounding rock and underground pressure appearance law around 0908 mechanized extraction working-face and to determine the reasonable roadway anchor supporting parameters on the basis of large quantities of research. Some conclusion was drawed from analysis of simulation results:(1) Roadway was tunneled in coal seam ,which could make stress of surrounding rock redistribute and offer free space for moving and deforming of the surrounding rock of the roadway .Because size of cross section of the tunneled roadway was relatively small,affacting range of which was not so large on coal and rock mass.Appearance of rock pressure was not obvious, and distribution of the stress in surrounding rock tended to be balanced as prolonging of the roadway's tunneled time.(2)Distance between first roof pressure of 0908 working-face in Shenhua group Pinggou coal mine and open-off cut was 18m~21m .Place of periodical pressure was30m~33m far from open-off cut and distance of which was 9m~12m.Periodical pressure appeared every 9m~12m in the later extraction,distance of periodical pressure shortened obviously and ground pressure was obvious when pressure came.Affection range and intensity of advanced supporting pressure was obtained from analysis on stress and plastic damage of the coal wall ahead of the working-face.(3) Compared with no supporting in tunnel ,charactoristic of stress and deformation was improved when anchor rod was used to support roadway,which showed that anchor supporting could be used in such geology condition and could meet the need of production .(4)A conclusion was drawed through numerical simulation calculation about different anchor parameter in roadway surrounding rock with a certain condition that the longer diameter and length of anchor was and the less distance between every two row was, the better effect of supporting was .At the same time reasonable anchor supporting parameter of 9# coal seam in Pinggou coal mine was obtained,which ensured safty of roadway and made every anchor play its most important role in the process of supporting.Simulating results showed that coal seam tunnel anchor supporting was possible and was benefit to refine roadway maintaince status and safe extracting condition. The research result provided theoretical basis to coal seam tunnel anchor supporting and also provided helpful reference to the supporting of roadway in the same condition.