Damage evolution analysis and pressure prediction of surrounding rock of a tunnel based on rock mass classification

Based on the relationship between each classification index for underground chambers and the elastic wave velocity of rock mass, a corresponding relationship between the classification of rocks that surround underground chambers and the initial damage variable is established by using the wave velocity definition of the initial damage variable of rock masses. The relationship between the damage variable and material parameters, such as elastic modulus, Poisson's ratio, cohesive force, and friction angle, is obtained through an analysis of damage evolution during excavation. The analysis method of damage evolution is further established by considering degradation of surrounding rock parameters. The elastic wave velocity is combined with the empirical formula based on the empirical formula of the rock pressure prediction model. The evolution tendency and rock pressure prediction model of the road tunnel is established. However, the numerical method is combined with the characteristic curve method based on the numerical simulation of progressive failure of the surrounding rock. The prediction results from the two models are compared with the field data, which can verify the reliability of the prediction model for pressure of the surrounding rock. A prediction method for the evolution tendency of rock pressure in a road tunnel is proposed. © 2014, EJGE.