Physical simulation study on failure process of horizontal strata soft rock roadway in Qishan Mine

For recognizing deep engineering complex rock mass deformation and failure mechanical behavior,taking horizontal stratified sedimentary rock masses as t he research object,the authors carried out physical modeling experiment to study the deformation and crack propagation characteristics of horizontal stratified soft rock roa dway. The field background for the experiment was main connecting tunnel located at depth of- 1 000 m in Qishan Mine. The variation of in- plane stress of the model rock mass was measured and deformation process was recorded by a video camera simultaneously. Crack initiation and propagation process during the test was analyzed base d on the video photos and the stress of the key monitoring points was analyzed based on the measured stress data sets. The experimental results showed that under the gr avity stress and tectonic stress,crack initiation occurred at the bottom of the roadway at first. Then the cracks appeared on the side and top of the roadway. Ultimately a co mplete failure of the roadway occurred due as coalescence of the propagating cracks under the increasing loads.