非构造应力下圆形巷道的内部变形破裂规律研究

Research on the law of internal deformation and cracking of circular tunnels under non-tectonic stress

为获得高应力作用下岩体内部的变形破裂时空演化规律，以平煤集团的一条深埋巷道为背景，分别采用透明岩体相似材料和三维离散颗粒流软件PFC3D对其开挖过程进行物理模拟和数值模拟，并在获得岩体内部变形破裂随开挖时间的发展演化规律的基础上，提出深埋圆形巷道的支护对策。研究结果表明：1）本文提出的透明岩体实验方法能够有效获得深部岩体的内部变形破裂时空演化规律。2）巷道顶底板处的岩体径向位移y均与其距巷道表面的距离x呈指数衰减关系；围岩变形在巷道刚开挖通过的1~2h内增长速度最快，当开挖通过2h后，如不进行后续推进开挖，围岩变形发展就基本保持稳定。3）巷道开挖后，巷道顶底板处的岩体均不发生破裂，而巷道两帮岩体则在拱腰处先出现剪切滑移破裂并随时间逐渐往深部和顶底板方向扩展。

To obtain spatio-temporal evolution rule of deformation and fracture in the rock under high pressure stress, set in a deep roadway of Pingdingshan Coal Mining Group, physical and numerical si-mulation of excavation process has been performed by using transparent rock-similar materials and three-dimensional particle flow code software called PFC3D. The evolution rule of deformation and fracture in the rock changing with excavation process has been acquired. On this basis, supporting measures of deep circular roadway have been put forward. Research results are as follows：1） The expe-rimental method of transparent rock in this paper can effectively obtain the spatio-temporal evolution law of the internal deformation and cracking in deep rock mass. 2） Rock radial y-displacement at the roof and floor of model roadway decreases in an exponential relationship with the distance x from the roadway surface;after excavating, the deformation of surrounding rock grows fastest within one or two hours, and the deformation keeps basically stable two hours later without further excavation. 3） Rocks at the roof and floor of roadway don’t break after excavation, while shearing slippage fracture of rocks at the two sides appears in the hance and gradually expands into great depth in the direction of roof and floor with the passage of time.