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Abstract The lengths of the piles are larger than their diameters, so the vibration isolation of incident plane P waves by the discontinuous barriers composed of a row of elstic hollow pipe piles can be simplified as two-dimensional plane problem. The expansion method of wave functions and Graf’s addition theorem are adopted, the stresses and displacements at the boundaries between the piles and their adjacent soils are considered as continuous and the inner boundaries are free, and then the theoretical solutions are obtained about the vibration isolation. Finally the effects of the piles’ thickness, the modulus ratio of piles to their adjacent soils, the distance between the piles and number of piles on the vibration isolation are studied, and some important conclusions are drawn out, which are that: (1) the isolation effects increase when the piles’ thickness and the distance between the piles deccrease, (2) the isolation effects increase with the modulus ratio of piles to soils, but when the ratio is larger than 500, the isolation effects increase little and are appromimate to those of rigid piles, (3) when the number of piles increase, the best isolation areas increase, and the position with best isolation effects moves forward, which provided theoretical basis for the design of discontinuous barrier for vibration isolation.
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Received: 06 February 2009
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2010, Vol. 31 
