Numerical simulation and experimental study of Parallel Seismic test for piles

Abstract

The theoretical capabilities of the Parallel Seismic (PS) test for determining the length of piles and characterizing possible defects are investigated in this paper. In deriving the theory, a correction factor is proposed in this paper to enhance the accuracy of the prediction. An axisymmetric finite element (FE) model was developed to carry out a series of parametric studies which included the effects of the pile length, the pile-to-borehole distance and the stiffness of surrounding soil. A miniature experiment using an aluminum bar embedded in epoxy prism was also designed and tested in the lab to verify the theory and to demonstrate the use of the correction factor. The results from the experiment and the numerical FE model were also compared to expose the potential of this nondestructive method to in situ application. The model was further modified to simulate the PS test on defective piles with axisymmetric necks and bulges. It can be concluded that the geometric configuration of a pile and the possible significant defect can be characterized with this nondestructive test.

PS wave based parallel seismic test for pile length assessment

“…2(b). This is the principle of conventional parallel seismic tests (Liao and Roesset, 1995;Liao et al, 2006;Huang and Chen, 2007;Lo et al, 2009;Ni et al, 2011;Huang and Ni, 2012;Niederleithinger, 2012;Lu et al, 2013;Zhang and Chen, 2013). Evidently, the slopes of the two fitting lines are affected by the velocity of the P waves in the pile and the velocity of the P waves in the soil below the pile tip.…”

Inclination correction of the parallel seismic test for pile length detection

“…The first method was proposed by Liao et al [7] based on the ray path theory, in which the true shaft length L is calculated as follows:…”

“…However, the borehole might be inclined due to inappropriate installation and the effect of this on the determination of pile length has not been considered in the literature. In the following section, we adopt the ray path method, similar to the derivation procedure in Liao et al [7], to derive the inclined correction factor of the PS test.…”

Analysis of Factors Affecting Bearing Capacity of Large Diameter Single Piles of Offshore Wind Power under Earthquake Loads

“…In terms of numerical simulation, Yan Maotian, Lu Aizhong et al (2005) considered the interaction effect of pile-soil, established a finite element calculation model for seismic response analysis of pile foundation structures, and carried out the overall finite element numerical calculation in the time domain. The structural analysis method and the finite element numerical calculation method verify the validity of the finite element calculation model [9]; Liao. et al (2006) studied the numerical simulation of the parallel seismic test of single pile foundation and established the axisymmetric finite element (FE).…”