Study On The Distressed Zone Of Longwall Face Along Strike In Outburst Coal Seam

In the recent years, coal and gas outbursts become increasingly serious at the working face in our country. Study on coal and gas outburst to working face still less and remain to perfect further. In order to solve the actual problem, the distribution law of abutment pressure in front of coal wall, the stability in distressed zone, the length of distressed zone that prevent the outburst, the measured length of distressed zone, which have been researched by the methods of theoretical analysis, field measurement, experimental research and numerical simulation to 2124 longwall face along strike of Sanhui No.1 mine in this paper. The conclusions can be a reference to prevent the coal and gas outbursts in 2124 face and be a demonstration to other faces with similar conditions. The main conclusions in this paper are as follows:(1) According to limit equilibrium theory, the distribution function of bearing stress in limit equilibrium zone which located in the front of longwall face along strike has been build and the stability of coal in limit equilibrium zone has been analyzed. The safety width of the distressed zone also has been obtained and applied to 2124 face with parameters of adjoining rock.(2) The pillar load in two-roadway, the value of drilling cutting and desorption index for drill cuttings in the front of face has been measured in field. The distribution raw of bearing stress in front of 2124 face has been analyzed and the measured length of distressed zone has been gotten.(3) Based on elastic-plastic theory and nonlinear finite element theory, ground pressure in longwall face along strike has been simulated with ANSYS. The distribution raw of ground pressure and the length of the distressed zone under the two situations of without drilling field and drilling field has been obtained and been used to verify the results of theoretical analysis and field measurement.(4) Considering the mechanism of coal and gas outburst in longwall face along strike, advancing hole and long drilling controlled and presplitting blasting were proposed to provent coal and gas outbursts in working face.