Study On Mechanism And Control Technology Of Rib Palling In Fully Mechanized Caving Face With Great Mining Height

The main development direction of thick seam mining process---large mining high-tech majorly mining the thick seam from3.5m to7m. Large mining height mechanized technology is widely applied and developed in our country, as a high yield and efficiency mining technology with its advantages of high resource recovery rate and the low refuse content. Along with the increasing of seam depth and mining height, rib spalling and roof collaspe have become the burning questions of the large mining high-tech. Therefore, it is very important to gain a correct understanding of the mechanical mechanism of large mining high-tech face in rib spalling, finding out the influence factors and the mechanism of rib spalling, establishing the stability evaluation model of coal wall in large mining height face and raising control measures for rib spalling.In this paper, on the basis of previous studies, based on3#coal seam4302working face in ChangPing coal co, LTD, integrated use of theoretical analysis, discrete element numerical simulation and in-situ measurement, analyze the rib spalling forms, mechanism and the rib stability influence factors on the large mining height, put forward the corresponding control measures aim at seriously rib spalling of mechanized mining working face. Main research works are as follows:1) Analyzed the strata structure characteristics, movement law and rib spalling mechanics in large mining height; Introduced the basic forms of rib spalling; revealed the mechanism of rib spalling.2) Established the plastic zone model of large mining height,analyzed the range of plastic zone and the maximum vertical stress on rib; at the same time used FLAC3D numerical calculation method combining with the measured data of a numerical simulation of the coal,and comparative analysis the results of numerical simulation and theoretical calculation results.3) using the state of general discrete element numerical calculation method, analyse the Mining height、Support strength and direction of working face advancing etc factors influence on mining of coal wall to help.4) describe the factors with affecting the coal wall stability of six of the semantic level, quantitative divided into various factors affecting the stability of different levels. On this basis, using the AHP analytic hierarchy process (AHP) working face of coal wall stability evaluation model is established, and the changping mine4302working face of coal wall stability has carried on the comprehensive evaluation.5) combination of changping coal mine4302mining geological conditions and mining pressure measured data analysis, in view of the working face of coal seam and roof are relatively soft, crushing, mining process of coal wall are seriously help, roof caving, proposed USES the high polymer chemistry grouting strengthening coal wall materials, and combining the wood anchor rod anchor reinforcement reinforcement measures of the fully mechanized coal face wall, the strengthening technology preliminary achieved the desired effect, improve the stability of the working face of coal wall, ensure the normal working face in mining.