The Stability Evaluation Of The Overlying Strata Of The Goaf For Shi Getai Mine Filed In Shen-fu Mining Area

Exploitation of coal resources undermines ecological balance of mining area, and triggers massive geological disasters, among which large area Mined-out area due to exploitation of coal underground is the most damage of geological hazard hidden trouble.Taking Shi Ge Tai mine filed in Shen-Fu mining Area for example, on basis of large field investigation and indoor comprehensive analysis, we analyses the stability factors toward overlying strata of the goaf and ameboid movement mechanism of the overlying strata. We also evaluate the stability of overlying strata of the goaf with fuzzy comprehensive evaluation method, and put forward reasonable treatment measures according to actual conditions ,which is important and meaningful to the treatments of geologic disaster. The results of the thesis are as follows:(1)The Shi Ge Tai mine field locates in the border zone of Mu Us Desert and Loess Plateau.At present, there are eight overlying stratas among this mine field with an area of 4.71 square meters. Overburden failure mainly includes bending breakage and shear breakage. Overlying strata movement is not reflected in the Three-Zone characteristics.with the moving forward of the coal face, pressure arch on the stope develop to the up strata gradually. when it develops a certain extent ,the pressure arch stop moving toward rock formation, but by coal face. When the distance of stope face is done about 1/4-1/2 H0 since Open-off Cut, the influence of exploitation affect the surface and cause surface subsidence.(2)According to Fuzzy Comprehensive Evaluation Method,we established multi-factor evaluation model about the stability of overlying strata of the goaf which help us to choose 13 main impact-factors in three aspect (engineering geology, environment and hydrogeology)as our evaluation index. We assure the weight of evaluation factor followed by analytic hierarchy process,and determine membership function by four valued logicdiscrete method, then conduct composition operations according to fuzzy composite operators of weighting meantype.Finally we get the comprehensive evaluation result of overlying strata of the goaf on the principle of maximum membership degree law. By the grading standard of stability of overlying strata of the goaf,we rank four grades in stability with inferior ,poor ,medium and good(3)According to the actual situation and grading standard of stability, we take measurements of closed isolation and filling and grouting to deal with overlying strata of the goaf.