湿度应力场作用下煤矿穿膨胀岩钻孔缩径规律研究

Study on coalmine boreholes shrinkage rule crossing swelling rock under the humidity stress field

针对煤矿穿膨胀岩钻孔遇水缩径问题,本文基于湿度应力场理论,借助有限元分析程序,通过引入湿度修正系数ψ(w),推导出了综合考虑围岩遇水软化和膨胀特性的钻孔孔壁位移修正解析解。并结合数值模拟软件ANSYS和相似模型实验,研究和分析了湿度场和地应力场对钻孔缩径变形的影响。结果表明,随着钻孔围岩含水率的增加,钻孔孔壁位移呈非线性递增,钻孔孔壁呈两端粗中间细的"哑铃形",钻孔中部为孔壁最大径向位移处;含水率变化引起的岩性软化对钻孔缩径影响显著;随着地应力的增大,钻孔孔壁位移呈线性增加,增幅较小;湿度场和地应力场对煤矿穿膨胀岩钻孔缩径都产生不可忽视的影响,就影响程度来看,湿度场影响最大,地应力场次之。

In response to the issue of boreholes shrinkage crossing swelling rock in coal mine, in this paper,based on the humidity stress field theory, analytical solution of boreholes displacement consid-ering humidity damage and expansion has been deduced by using finite element analysis program and introducing humidity corrected coefficientψ（w）.So,the effects of the humidity field and stress field on boreholes shrinkage are systematically studied and analyzed by the software ANSYS and similar model experiment. The results show that with the water ratio of surrounding rock increasing, the wall dis-placement of boreholes is nonlinearly growing;the wall is“dumbbell-shaped”with two ends crude and intermediate fine;the maximum radial displacement is in the central wall of the boreholes;the effect of lithology softening resulting from the boreholes shrinkage is obvious;as ground stress increases, the wall displacement of borehole increases linearly but has a small increase;the above two fields have enormous effects on boreholes shrinkage. As far as the degree of influence is concerned, humidity field causes the larger influence, followed by stress field.