HIGH-GRADIENT MODELING FOR LOVE WAVE-PROPAGATION IN GEOLOGICAL-MATERIALS

Based on a microstructural approach, geological material, owing to its discrete nature, can be represented by an equivalent continuum of the high-gradient type. The high-gradient continuum differs from the perf ectly elastic continuum by having a characteristic length scale that i s an intrinsic property of the material. Using the high-gradient stres s-strain relationship, we formulate a fourth-order wave equation to de scribe the propagation of a Love-wave in a two-layer medium. We employ Hamilton's principle to derive the additional boundary conditions inv olved in the differential equation. The differential equation is then solved to study the effects of characteristic length on the wave propa gation in geological material. Comparisons are made between the predic ted and observed wave velocities in a two-layer geological medium duri ng an earthquake.