Several rows of piles as barriers to isolate shear waves in saturated soils

There are three types of waves propagating in the saturated soils, which are fast pressure waves (P1 waves for short), slow pressure waves (P2 waves for short) and shear waves (S waves for short), and their wave numbers are firstly given in this paper. The lengths of elastic piles are much larger than the diameters in order to obtain ideal isolation effectiveness, so the isolation of SV waves by discontinuous barriers composed of several rows of piles can be simplified as a 2-dimensional plane problem. The conformal mapping method of complex functions and expansion method of wave functions are adopted, the incident, scattered and refracted waves are all expanded to the special functions with infinite series, the stresses and displacements are considered as continuous at the boundaries between the piles and adjacent saturated soils, and finally the theoretical solutions about the complex coefficients of the expanded potential functions are obtained. The normalized vertical displacement amplitudes are introduced, which are the ratios of displacement amplitudes of saturated soils caused by both the incident and scattered waves to those only by the incident SV waves, the isolation effectiveness of the barriers composed of one, two and three rows of piles are compared, and the factors that influence the isolation effectiveness are analyzed, which provides some references on the vibration isolation design.

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