Study On The Statistic Damage Constitutive Model For Rock And The Rockburst Of Circular Chamber

The simulation of the rock failure process is the emphasis of the research of the rock mechanics. The introduction of statistic damage theory provides an effective idea and approach for it. But there are some defects in the statistic damage constitutive models of rock based on this theory, it can't reflect the characteristics of rock during different deformation stages and the linear-elastic characteristics of rock deformation in low stress level and residual strength, furthermore, the existing constitutive models are confined to theoretical analysis. How to use it to particular projects need further investigated. For these, study was developed in this paper to solve the problems, which is of great theoretical and practical significant. The contents are as follows.(1) The statistic damage constitutive model of rock was established basing on the continuum damage mechanics and strain equivalent assumption, and two deferent representative volume element rock constitutive models were proposed. Moreover, the underlying probabilistic distribution of the physical and mechanical property of the representative volume element using in the rock failure process analysis was described briefly.(2) By analyzing the characteristics of rock stress-strain curve and damage, the statistic damage constitutive model was improved. It included the introduction of considering the influence of the damage threshold and residual strength, solution methods of model's parameters and model generalization under complicated stress states.(3) Based on the theory of rock statistic damage, the Druck-Prager criterion was modified considering the characteristics of rock stress-strain curve during the full process of rock failure. The rationally about this rock strength rule after modifying had been shown in example solution.(4) The requisite condition of rockburst and their influence factors were introduced briefly first. Then, on the basis of research on the existing rockburst prediction criterion, the rockburst formation mechanism for circular chamber was analyzed considering surrounding rock damage. The analyticsolution of surrounding rock stress redistribution was also determined. The critical load and critical damage softening depth of the chamber rockburst were obtained using statistic damage constitutive relation and the characteristics of surrounding rock stress-strain curve. This method was feasible for predicting and preventing the rockburst. The prevention measures were also discussed in this paper.