Axisymmetric Stress Wave Propagation in Sand

Experiments were conducted in which a rigid cylindrical weight was dropped onto the surface of a bed of sand. Soil stress gages and soil strain gages embedded in the sand were employed to measure the soil response to the impacting weight. These measurements were analyzed to determine the effects of inertia on the soil behavior. Experimental results indicated, due to soil inertia during the intial phases of the impulse loading, the displacements were elastic with plastic behavior being evident in the stress measurements. Beyond the initial phase the inertia effects decreased and plastic behavior was noted in the strain and displacement measurements as well as the stresses. The results further indicated the response of a footing to an impulsive load may be divided into different inertial regimes depending on the rise time of the transient load.