Horizontal and vertical motion at the surface of swelling poroelastic layer sandwiched between water and elastic solid

Abstract

The horizontal and vertical motions at the surface of swelling poroelastic layer in coupled system are investigated. Coupled system means water-swelling porous sediment-elastic solid substrate system. The analytical expressions of horizontal and vertical displacements at the surface of swelling porous solid are evaluated for both incidences i.e., P and SV waves. The closed form analytical expressions for reflection and transmission coefficients are derived theoretically for appropriate boundary conditions. The horizontal and vertical displacement amplitudes are derived analytically in terms of reflection and transmission coefficients. The horizontal and vertical motion of swelling poroelastic layer is examined through analyzing three key factors: amplification coefficients, displacement amplitudes and displacement ratio. The impacts of wave frequency, thickness of swelling poroelastic layer, incident direction and swelling property of the medium are examined on these three key factor numerically. Numerical results indicate that the surface motion strongly depends on wave frequency, thickness of layer, swelling property of the medium and incident direction.