Prospecting soft deposits by wave propagation analysis in theory and experiment

A method using numerical integration in frequency wave-number domain and a special solution for the wave compliance of horizontally layered soils has been applied to study wave propagation in layered soils. The wave field induced by horizontal or vertical point loads on the surface of the soil can be calculated. Both amplitudes and dispersion curves have been determined for observation points on the soil surface (Auersch 1994). Experimental studies with an impulse hammer technique - yielding wave speeds and wave amplitudes - were performed at different sites including soft deposits with wave speeds of 15, 30 or 100 m/s (Said et al. 1990). The results of theory and experiments are shown and compared. The main conclusions are:• the soil exhibits certain filter characteristics due to layering and material damping,• the horizontal components are greater than the vertical ones even for moderate soil layering.Some consequences for structures on soft soil, viz. results of the boundary element method (Auersch & Schmid 1990) and those of experiments on block foundations, will be discussed briefly.

• 1 INTRODUCTION

• 2 EXPERIMENTS ON WAVE PROPAGATION

• 3 THEORY OF HOMOGENEOUS AND LAYERED SOILS

• 4 THE USE OF SOFT SOIL: EXPERIMENTS ON A BLOCK FOUNDATION

• 5 LITERATURE

• ACKNOWLEDGMENT