Static And Dynamic Constitutive Relation Of Rock And Application Study

Research on static and dynamic constitutive relations of quasi-rock materical is the theoretical basis and key issues in geotechnical engineering.The strain rate effects on the materical properties under dynamic loading is a basic information in establishing the dynamic constitutive relations .A constitutive model considering the strain rate effect which has relatively simple forms and be easily used in practice is of great importance.An elastic-viscoplastic damage model of rock is proposed in this study.The strain rate effects on the material properties has been considered in the model .The stress-strain relationship under various strain rates obtained from this model are compared with test data and good agreement can be observed .The radius of crush zones and crack zones of surrounding rock deduced by blast wave are investigated based on unified strength theory. The energy dissipation distribution of air coupling charge is also discussed. Numerical simulations are performed to investigate the damage zone of rock mass deduced by underground explosion .The effects of rock quality and loading density on the damage zone are investigated and regression formulas are obtained based on the numberical results. The phenomenon of rock burst and its prediction are reviewed and studied. The tangential stress formula of surrounding rock under complex stress state based on unified strength theory is derived. The case studies has been carried out and compared with test data in practical engineering and it is shown that it can be used for prediction of rock burst based on Russenes criteria . The following conclusion can be drawn based on the above study.1. The proposed elastic-viscoplastic damage model for rock materials can be successfully used in practice. The parameters in the model can be determined by esperimental results.2. The formula of crush zone and crack zone derived in this study based on unified strength theory can reasonably predict the damage zone of rock mass deduced by blast load. The numerical results show that the rock quality and loading density has obvious influences on the blast pressure around the charge hole and the damage zone of the surrounding rock mass.3. The tangential stress of surrounding rock under complex stress increases with the - strength criterion coefficient and the ratio between tensile strength and compressive strength, while it decreases with the increase of intermediate principal stress parameters.