基于透明岩体的深埋软岩巷道变形破裂规律研究

Study on deformation and cracking laws around deep soft roadway based on the transparent rock

针对深部岩体物理模型试验中存在的内部变形量测难题,采用透明岩体相似模拟试验新方法,利用自行研制的数字散斑相关变形量测技术,通过进一步对模型内部制斑方法展开实验研究,得到了非构造应力作用下深埋圆形软岩巷道围岩的内部变形与破裂规律。研究结果表明:1)提出的透明岩体人工填充式制斑方法能够有效保障数字照相变形量测的实施与精度;2)不同埋深下,围岩的径向位移与其距巷道表面的距离大体呈指数衰减关系;3)围岩的宏观裂纹数目、总长、破裂区域宽度与其埋深呈指数增长关系,而破裂分形维数则与埋深呈线性增长关系;4)巷道两帮及对角线处的浅部岩体为重点锚喷支护与注浆加固区,同时,应采用桁架、格栅等构件形成封闭支护结构和有效承载环,防止巷道发生滑动失稳破坏。

In the physical model test of deep rock, the measurement on the internal deformation and rupture is a challenge. In order to solve the problem, based on the transparent rock simulation experiment, the digital speckle correlation deformation measurement method has been adopted and the spot methods have been further studied. On the basis, spatio-temporal evolution law of the internal deformation and rupture in deep circular tunnels without tectonic stress has been obtained. The conclusions are as follows： 1） the artificial filling spot method of transparent rock presented in this article could guarantee the implementation and accuracy of digital photographic deformation measurement; 2） under different buried depths, the radial rock displacement at the roof, bottom and two sides is in an exponential attenuation relationship with the distance from the roadway surface; 3） the number and overall length of macroscopic crack as well as the width of failure zone are in an exponential growth relationship with the depth, and the rupture fractal dimension satisfies linear growth condition with the depth; 4） under the tectonic stress, the shallow rock in the two diagonals should be key supporting parts around deep circular roadway. In addition to spraying anchor supporting of roadway, grouting reinforcement is necessary to the shallow rock in two sides and diagonal. The supporting structure around the tunnel should be linked into a unified whole unit by truss and grilling, forming an effective bearing ring to prevent sliding instability failure of roadway.