沟壑地貌对上覆岩层破断角的影响研究

Influence of hilly and gully terrain on the breaking angle in overlying strata

基于沟壑地貌对采场矿压显现有较大影响的工程实际,以王家岭煤矿12309工作面为研究对象,采用理论计算与相似材料模拟的方法,针对沟壑地表对岩层破断角的影响规律进行了研究。结合弹性力学及岩石力学理论,建立了岩梁破断角力学模型,推导出了包含岩梁破断角α与岩梁承载载荷q、岩梁抗拉强度R T及岩层内摩擦角φ的岩梁破断角的理论公式。岩层破断角α随抗拉强度R T的增加而呈对数函数形式增加。岩层破断角α随岩层载荷q的增加呈现二次函数形式减小,且岩层破断角α范围在60°~70°之间。相似材料试验表明:谷底处应力大于坡顶,上坡开采阶段裂隙更为发育,且关键层下沉量较大,谷底处有应力集中现象,同时通过相似模拟试验验证了破断角计算公式的合理性。

Based on the engineering practice that the gully landform has a great influence on the mine pressure appearance in the stope,taking the 12309 working face of Wangjialing coal mine as the research object,using the method of theoretical calculation and similar material simulation,this paper studies the influence law of the gully surface on the rock fracture angle.Based on the theory of elasticity and rock mechanics,the mechanical model of rock beam fracture angle is established,and the theoretical formula of rock beam fracture angle including rock beam fracture angleα,rock beam bearing load q,rock beam tensile strength R T and rock friction angleφis derived.With the increase of the tensile strength R T,the fracture angleαincreases in the form of logarithmic function.With the increase of rock load,the fracture angle decreases in the form of quadratic function,and the range of fracture angle is about 60°-70°.Similar material tests show that the stress at the bottom of the valley is greater than that at the top of the slope,the cracks are more developed in the mining stage of the uphill slope,and the subsidence of the key layer is large,and there is stress concentration at the bottom of the valley.At the same time,the rationality of the calculation formula of the fracture angle is verified by similar simulation tests.