恒阻大变形锚索支护巷道变形机制模型试验研究

为解决深部软岩巷道大变形问题,以口孜东矿千米深井巷道为工程实例,采用理论分析及物理模型试验的方法,对恒阻大变形锚索支护巷道的围岩变形机制进行研究。首先基于弹性力学理论,将直墙半圆拱断面巷道简化成圆形断面巷道,得出圆形巷道在恒定支护力、不同应力条件下围岩应力分布特征及巷道位移的解析解。其次基于相似理论,设计并完成模型恒阻锚索巷道支护试验,试验结果表明,随着围岩应力的增大,巷道位移程度增大;随着(水平)构造应力增大,巷道缩帮逐渐大于顶底板移进量,构造应力对稳定性影响显著;恒阻大变形锚索能够将应力向深部转移,使锚索锚固区岩体发挥支撑作用。将巷道围岩位移理论计算值与模型试验中各阶段监测值进行比较,结果吻合较好。与现场监测对比发现,巷道变形规律与试验变形规律一致巷道表面位移误差在5%以内,说明模型试验具有一定的参考性。

Model test study on deformation mechanisms of roadways supported by constant resistance and large deformation anchor cables

In order to solve the problem of large deformation of deep soft rock roadways,a kilometer deep roadway in Kouzidong coal mine was taken as the engineering example and the deformation mechanism of surrounding rock of the roadway supported by constant resistance and large deformation(CRLD) anchor cables was studied by means of theoretical analysis and physical model test. Firstly,the semi-circular arch roadway with straight walls was simplified into a circular roadway,and the distribution characteristics of surrounding rock stress and the analytical solution of roadway displacement under constant support force but different stress conditions were obtained based on the theory of elastic mechanics. Secondly,the roadway support experiment with constant resistance anchor cables was designed and carried out based on the similarity theory. The results show that the displacement of the roadway increases with increasing the surrounding rock stress and that,with rising the horizontal tectonic stress,the deformation on both sides of the roadway is gradually larger than that on the roof and the floor,indicating that the tectonic stress has a significant impact on the stability. It is also revealed that the CRLD cable can transfer stresses to the elastic zone,so that the rock mass of the anchorage zone plays a supporting role. The theoretical calculation values of roadway surrounding rock displacement are compared with the monitoring data in the model experiment,and a good agreement is obtained. Comparisons of the roadway deformation between the field monitoring and experimental results also give a good consistence with less than 5% of the surface displacement error of the roadway,which indicates that the model test has certain reference value.