Numerical investigation on optimal blasting parameters of tunnel face in granite rock

Overbreak induced by drill and blast method occurs during rock tunnelling. In this study, the performance of three constitutive models for rock material (Riedel-Hienmaier-Thoma, HomlquistJohnson-Cook, and plastic kinematic models) in simulation of blast-induced rock cracks was investigated, to improve the accuracy of the numerical simulation. The results indicate that the two conventional blast-induced crack simulation methods in LS-DYNA have certain limitations. In contrast, the Riedel-Hienmaier-Thoma (RHT) model characterise the tensile failure behaviour and dynamic fracturing process in rock blasting. Several numerical simulations were performed to quantify the optimal blasting parameters based on the engineering background. An optimal blasting parameters design was proposed and compared with the original blasting parameters. The outcome of the field test demonstrated the feasibility of the optimal blasting parameters.