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矿山巷道喷层支护致使围岩应力重新分布。根据岩体声波传播速度与应力有一定的相应关系,用声波法对某矿山巷道喷射混凝土前后不同时间的围岩应力变化进行了实测。本文以测得的纵波速度Vp为依据,探讨矿山巷道喷层支护的作用机理。结果表明,喷前与喷后围岩的亩波速度发生变化,且随着喷层龄期的增加而增加。在28天龄期以前,声速变化主要在围岩松动区范围内,而后逐渐扩展到松动区范围以外。原来的低速区转化为高速区,即低应力区转化为高应力区。这标志喷层与围岩形成了统一的承载结构体,支承着作用于巷道围岩的压力。
The mine roadway shotcrete support causes the stress of the surrounding rock to redistribute. According to the corresponding relationship between rock mass acoustic velocity and stress, the stress change of surrounding rock at different time before and after shotcrete injection in a mine roadway was measured by acoustic method. In this paper, based on the measured longitudinal wave velocity Vp, the mechanism of mine roadway shotcrete support is discussed. The results show that the velocity of mu wave changes before and after spraying, and increases with the increase of spray age. Before the 28-day-old, the change of sound velocity was mainly in the range of rock loosening area and then gradually extended beyond the loosening area. The original low-speed area into high-speed area, the low-stress area into high-stress area. This marks the spray layer and the surrounding rock form a unified bearing structure, supporting the pressure acting on the rock surrounding the roadway.