Abstract:With the increasing geostress level faced by rock roadway (tunnel) engineering, the stability and maintenance of roadway are becoming a bigger challenge, and higher requirements are put forward for the understanding of unloading deformation characteristics of surrounding rock. It is necessary to master the deformation and failure mechanism of rock and surrounding rock under roadway (tunnel) excavation and unloading conditions. In view of this, based on the triaxial test system, polymethyl methacrylate is taken as a specimen to simulate the elastic stage of natural rock mass under secondary stress state, and explore the influence of roadway surrounding rock unloading in the elastic stage on the secondary stress state. The deformation of the specimen is solved by using the elastic deformation theory of natural rock mass under the condition of excavation and unloading, and compared with the test results. The results show that only elastic deformation occurs to the specimen during the test, and the deformation in the middle part is greater than that in the end; the larger the deformation of the surrounding rock near the tunnel wall, the less the deformation of the outer side of the specimen is than that of the inner side; the theoretical deformation value matches well with the experimental deformation value.
