Analysis of Nonlinear Dynamic Characteristics in Saturated Soil with Blast Wave Diffusion and Damage to Its Effective Strength

Explosions release energy and generate shock waves. Analysis of how shock waves damage transmission media is crucial in protection engineering. Soil liquefaction due to explosions occurs in a highly nonlinear manner. The time point at which soil receives stress waves has yet to be determined. Therefore, this study analyzed the dynamic reaction and liquefaction phenomenon that protects soil after it has received a shock wave. A numerical analysis model was developed and verified through on-site explosion experiments for measuring ground acceleration and excess water pressure. Finite element analysis was employed to establish a numerical analysis model based on experimental site conditions. The LS-DYNA finite element program was used for numerical simulations. The analysis model had a three-dimensional structure with fluid-solid coupling and consisted of eight-node elements. To analyze the dynamic reaction and liquefaction phenomenon that occurs after soil has received a shock wave, a multimaterial arbitrary Lagrangian-Eulerian calculation model was combined with an element erosion algorithm. Meshes were overlapped to achieve fluid-solid coupling for subsequent analysis. The nonlinear dynamic reaction in soil triggered by shock wave transmission and the liquefaction of the material due to excess water pressure were analyzed. The research results showed that the relative errors between numerical analysis and experimental results were within 10%, verifying that the fluid-solid coupling numerical model developed in this study can effectively be used to analyze the dynamic reactions of materials receiving shock waves. Shock waves from both multisite time-delayed explosions and from continual explosions at a single nearby site lead to soil liquefaction. Compared with single-site explosions, multisite time-delayed explosions more easily trigger liquefaction in saturated sandy soil. Analysis of shock wave transmission characteristics and ground shock effects revealed that at a distance of 600 cm from the explosion center, the shock wave was substantially attenuated. The results of shear strain failure analysis indicated that soil liquefaction had an approximate area of scale distanceZ = 30.81-64.89 cm/g(1/3)and approximate depth ofZ = 17.62 cm/g(1/3). The results verify the validity of the numerical model and algorithm developed in this study, which can describe the liquefaction process of saturated soil under explosion loading.