主应力演化影响下的深部巷道围岩变形破坏特征试验研究
Experimental research on characteristics of deformation and failure of surrounding rock of roadway in deep mine under influence of principal stress evolution
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摘要: 研究主应力变化对深部巷道围岩变形破坏特征的影响是巷道支护中非常必要的。以某矿处于深部高水平应力条件下的巷道围岩为工程背景,以大尺度三维相似材料模拟试验系统和制作的主方向应力传感器量测工具,采用“先加载后卸载”的开挖方式模拟主应力大小和方向演化影响下的有支护巷道围岩产生剪切滑移的变形破坏特征。研究表明,在高水平应力环境下巷道在掘进开挖过程中顶底板受挤压剪切作用产生变形破坏,破坏范围呈现“楔形”渐进发展;通过模型剖切面发现巷道围岩顶底板产生了不同数量的对称螺旋状剪切滑移裂缝,并向巷道两帮发展并交叉,将巷道围岩形成一定范围的剪切破坏区域;通过分析主应力大小及方向的演化可知,巷道围岩受高水平应力作用形成的剪切滑移裂缝破坏与主应力大小及方向演化存在必然联系,认为最小主应力的调整对剪切滑移裂缝的形成起到了重要作用。Abstract: It is necessary to study the characteristics of deformation and failure of surrounding rock of roadway under influence of the principal stress for roadway support. Based on the surrounding rock of roadway with high horizontal stress in a deep mine, the characteristics of shear and slip with support method are physically simulated by using a large-scale three-dimension test system and principal direction strain sensors. The simulation method of loading first and then excavation is carried out. At the same time, the influences of degree and direction of the principal direction stress are taken into account. The results indicate that the roof and bottom of roadway fail due to pressing and slipping under the high horizontal stress. The development of failure range exhibits 'wedge' shape. By observing the section of model, there are different shear slip fractures with the form of symmetric helical segments at the roof and bottom during drilling. The fractures expand to the wall and cross at last. The shear failure zone is formed at the surrounding rock. The shear slip fractures formed by the high horizontal stress are linked to the evolution of the principal stress by analyzing the direction and degree of the principal stress. The evolution of the minimum principal stress plays an important role in the formation of shear slip fractures.