旁孔透射波法确定桩底深度计算方法评价

On Determination of Pile Length with Parallel Seismic Testing for Existing Structures

本文首先扼要综述了旁孔透射波法(parallel seismic testing)检测既有建筑基桩底端深度的分析方法。对均质地基,建立了一个旁孔透射波法的首至P波传播路径的简化计算模型,分析了首至P波历时与孔深关系图形的主要特征,再由此对确定桩底深度的既有方法进行了评价并提出了修正。利用文献中的一个有限元算例结果初步检验了本文结论的可靠性和简便实用性。

The problems in determination of pile length with the parallel seismic testing （ PST ） for existing structures is firsdy reviewed in this paper. A simplified model for the propagation path of the first - arrival P wave in the PST is then proposed to get the main features of time - versus - depth plot. When the measurement depth is big e- nough in the borehole nearby the pile, the plot usually involves two straight lines and the slope of upper one is related to the velocity of one dimensional P wave of pile shaft while that of lower one to the velocity of three dimensional P wave of soil beneath the pile tip. A reasonable method for pile length using PST is presented from the intersection point of the two lines, which is preliminarily verified with a FEM calculation in the literature.