断续节理岩体中围岩破裂区的试验研究

Model Experiments on the Broken Zone in Intermittently Jointed Surrounding Rock

为了研究断续节理对围岩破裂区形成与扩展以及破裂区大小的影响,采用真三轴巷道平面应变模型试验台,运用数字照相进行变形量测的方法,研究分析了断续节理岩体中裂纹的产生、扩展与贯通机理及其围岩的破坏失稳行为.结果表明:在断续节理岩体中,围岩破裂区是由于新生裂纹与原有节理相互贯通,导致岩体中产生纵横交错的贯通裂隙所致;在断续节理的影响下,巷道围岩破裂区并不是均匀发展,而是首先产生于顶板节理附近,然后向巷道周边其它相邻部位发展;最终的破裂区厚度在平行于节理方向最大,而在垂直于节理方向的厚度最小.

A triaxial roadway model and digital photogrammetry were used to analyze the deformation of the surrounding rock that had intermittent joints. The effect of the intermittent joints on the production, growth and size of the broken zone in the rock was investigated. Crack initiation, propagation and coalescence mechanisms as well as failure behavior of the rock are discussed. The results show that crack propagation and coalescence within the joints produce interlaced cracks in the surrounding rocks. Intermittent joints influence the development of a broken rock zone in a usually unsymmetrical way. The broken rock is produced primarily nearby the roof joints of the roadway and then it expands into the conjoint part. The maximum thickness of the broken rock zone parallels the joint while the minimum thickness is normal to the direction of the joint.