NUMERICAL INVESTIGATION OF THE FAILURE MECHANISM AND COUNTERMEASURES OF THE ROADWAY SURROUNDING ROCKMASS WITHIN DEEP SOFT ROCK

The roadways surrounding rockmass within deep soft rock are affected by high stress and strong disturbance, and the original joints and secondary fractures greatly develop, all of which leads to the inaccurate evaluation of mechanical parameters of rockmass and increases the difficulty of roadway support. Based on Baecher joint network model in RS2, this paper proposed a RockMaterial-JointNetwork (RM-JN) simulation method to reveal the deformation mechanism of the roadway surrounding rockmass within deep soft rock. Firstly, three sets of Baecher joint were selected to characterize the joint attitudes of sedimentary rock and the corresponding RM-JN uniaxial compressive models were established. Then, the mechanical parameters of elements and that of joints in the RM-JN model were calibrated, respectively, by comparison with the uniaxial compressive test results in laboratory. Next, the roadway RM-JN model was built by comparing the deformation results of roadway surrounding rockmass obtained through adjusting the joint density and length in the model with the deformation on site. And finally, a reasonable support scheme was proposed to effectively control the roadway surrounding rock failure within deep soft rock. During parameter calibration of RM-JN model of rock samples, it is found that the total number of joints is an important factor in affecting rock mechanical parameters. The RM-JN model proposed in this paper effectively simulates the mechanical behavior of deep soft rock samples and the deformation of the roadway surrounding rockmass so as to make it more suitable for the site. It also improves the accuracy of numerical simulation results and provides a valuable basis for improving the roadway support scheme of deep soft rock, which has great engineering application values.