Abstract: Blast-induced destruction in rock and soil is a research focus in geotechnical engineering. Based on a coupled smooth particle hydrodynamics-finite element method (SPH-FEM) algorithm in the frame of LS-DYNA, a numerical model of analyzing explosion in sand foundation is established to study the explosion effects of small equivalent group charges at different depths of burial(DOB). The crater depth reaching to maximum is prior to the crater diameter reaching its maximum value. The shearing flow of surface layer sand plays significant effect on the evolution of crater diameter. With the increase of DOB, a critical crater diameter can be obtained. Since it can be considered the crater diameter is only related to explosive equivalent and DOB, therefore a basically linear relationship is proposed between crater diameter relative to DOB and scaled distance. Compression waves appearing the similar features of strong discontinuous shock, dominate in the close-in region of explosion. Large deformation of sand is mainly induced by compression. At far field, the blast waves change to the continuous shear waves with reduced amplitude. Attenuation law of peak pressure has a good coincidence with the empirical predictions. The analysis results can provide reference for design and reinforcing of foundation structures to resist blast load.

Key words: coupled SPH-FEM algorithm, explosion effects, depth of burial, critical crater diameter, peak pressure