Design of overburden thickness for underground arsenals based on numerical simulation of underground explosion caves

This paper aims to optimize the design of overburden thickness for underground arsenals. The dynamic finite-element program ANSYS/LS-DYNA was adopted to numerically simulate the damage and failure process of two types of rocks (i.e., marble and granite) with different sizes and lithologies under the explosion load. The simulated results were verified against the data of a previous explosion test. The simulation was found to be reliable, for the simulated results agreed well with the test data. Based on the collected data, the authors thoroughly analyzed the damage effect of underground explosion on the cave under different overburden thicknesses and charge densities. The results show that the overburden thickness directly affects the limiting effect of the outer rock on the particle vibration of the inner rock; the vibration intensity on the free surface is significantly negatively correlated with the overburden thickness; the damage of underground caves has a steep nonlinear relationship with charge density. The research findings provide a guide for the future design of overburden thickness for underground arsenals.