Engineering Geological Characteristics And Stability Assessment Of No.4 Coal Seam's Roof In Huangyuchuan Coal Mine

The roof stability of coal seam is one of the major factors concerning coal mine safe production.Huangyuchuan coal mine in western central Zhungeer coalfield has longstanding roof problems during the mining process of 4#coal.Therefore,it's urgent to conduct an analytical research on the characteristics of its roof and have a quantitative evaluation of the roof stability by adopting reasonable methods in order to provide scientific basis for roof management.Based on sedimentary environment analysis,this paper studies the roof sedimentary properties and engineering qualities under different environments.The characteristics of rock mass structure are quantitatively described in accordance with fractal theory after the analysis of joints' distribution properties.After that,the distribution of rock compression strength and complete degree are obtained by analyzing the rock mechanics experimental data and the effects of deposition and tectonism.Through theoretical analysis and numeric simulation of the engineering geology data of 4#coal roof,the geological factors that affect roof stability are thoroughly studied and the quantitive assessment index and criteria are selected,on the basis of which the roof stability division of single factors is made.Base on the Analytic Hierarchy Process(AHP)and the expert system,the index weight is calculated with the assistance of MTALAB.This paper analyzes the defects of the traditional Fuzzy Comprehensive Evaluation Model(FCEM),improves the model,and makes a comprehensive assessment of 4#coal roof stability with the assistance of the image processing function of Mathematics.Four types of stability are thus classified,known as extreme-instability,instability,relative-stability and stability: stability roof mainly distributed in the eastern and northern regions,occupying 33%;relative-stability roof is commonly found in transitional region of sandstone roof pinch-out,accounting for 27%;instability roof accounts for 24.3% and distributes along fault zones;extreme-instability roof mainly distributes in flood plain and complex structure area,occupying 15.7%.The evaluation results are analyzed in connection to coal field production,and can show the practical condition of coal roof.Finally,corresponding roof management methods are given.Due to its simplicity and accuracy,this evaluation model,the author believes,can be widely adopted in engineering fields.