Abstract: Using miniature spherical explosive of 0.125 g TNT equivalent as explosion source and based on the observed velocities of radial particles of ? 1 370 mm×1 200 mm loess sample at 180-1 280 m•kt-1/3, the elastic modulus E=(1.927±0.216) GPa, bulk modulus K=(1.284±0.144) GPa and shear modulus G=(0.771±0.086) GPa are inverted by combining the assumption of strong discontinuous wave and variable modulus model. Assuming the loess as linear viscoelastic ZWT material for numerical simulation, the error function is defined using the particle velocity vmax , the particle displacement umax, and the corresponding time of vmax and umax obtained from the numerical simulation and experimental results respectively. When the error function gets minimum value, the relaxation shear modulus GM and the relaxation factor ? M are 0.13 GPa and 21 µs respectively. Using GM and ? M as the linear viscoelastic ZWT parameters, the numerical simulation of spherical stress wave propagation in loess is made. The results reveal that: the velocity curves obtained from the numerical simulation are consistent with the experimental results; the maximum deviations of vmax and umax are 8% and 6% respectively; the maximum deviations of the corresponding time of vmax and umax are 1% and 5% respectively; the radial stress ? r , the tangential stress ? ? , the radial strain ? r , the tangential strain ?? obtained from the numerical simulation are in good agreement with the results obtained from the assumption of strong discontinuity and variable modulus model.

Key words: explosion and shock, spherical wave, viscoelasticity, loess, attenuation