Liquifaction of fluid saturated rocks due to explosion-induced stress waves.

摘要

Shock-induced liquefaction of a water-saturated rock may occur during the passage of a large amplitude stress wave, such as that due to an explosive. We studied this phenomena numerically with the aid of a material model which incorporates effective stress principles, and experimentally with a gas gun. Our numerical model is capable of calculating material response for both small and large deformation and any initial saturation. Phase transitions of the solid phase and the water phase are also allowed. Fitting the model to dry gas gun experiments allowed reasonable predictions of nearly saturated experiments. Liquefaction, the loss of shear strength when pore pressure exceeds the mean stress, appears to occur during the unloading portion of these experiments. The pore crushing which occurs, even under fully saturated conditions, leads to greater attenuation of a stress wave, as well as liquefaction of the rock and a lengthening of the wave duration, as the wave passes. 12 refs., 4 figs.