Study on creep instability mechanism and key control technology of surrounding rock in deep soft rock roadway

Controlling the creep instability of the surrounding rock of the deep soft rock roadway is a necessary prerequisite to achieve safe mining operations. This paper takes Guqiao Coal Mine as the engineering background, uses experimental testing, theoretical analysis, industrial experiments, on-site monitoring and other methods to conduct in-depth research. The study results show that the strength of the surrounding rock of the deep roadway in Guqiao Coal Mine is weak, and it is easy to cause a significant decline in long-term strength, elastic modulus, cohesion and internal friction angle after immersion, rock softening, continuous expansion of floor loose zone and reduction of overall stability of surrounding rock; the special shape of internal and external bearing structure of surrounding rock is defined: approximate vertical ellipse, based on improving the stability of the bearing structure, the deep hole grouting technology of the bottom plate is proposed. The deep hole grouting of the bottom plate can quickly change the shape of the bearing structure and change the unstable approximate vertical ellipse shape into the approximate circular shape with high stability.