Study of the hard roof mechanical properties in the process of repeated coal mining
HU Qianting
TIAN Chenglin
TAN Yunliang
SUN Haitao
DAI Linchao
CAO Jie
Abstract：Based on the Hoek-Brown criterion which can reflect the nonlinear failure of the rock mass,the mechanical properties of hard roof were studied.The hard roof rock sample loading test with MTS 815 rock servo test system for different damage states was performed.The relationship between strength and confining pressure of hard roof under different damage degree was analyzed,the m,s values of different damage degree were obtained,the decrease rates of m and s were established to represent the damage degree of hard roof.Finally,the macroscopic failure characteristics of the hard roof were analyzed.The results show that the strength and confining pressure of the rock samples are the quadratic function;repeated mining caused m and s to be reduced in different degrees,but ηm,ηs are both increasing and ηm＞ηs;the hole leakage of overburden fractures is obviously increased,the spatial distribution of mining fissure zone changed obviously.
Keywords：hard roofrepeated coal-miningdamageHoek-Brown criterionmining fissure zone
Publication Date：2018-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：6( 67-72 )