Abstract

The traditional pile design method of dual-row pile wall (DRPW) occasionally considers the effect of flexural stiffness ratio between front row (FR) to rear row (RR). DRPW can no longer satisfy the requirements of settlement and deformation for substantial digging depth. This study evaluated the influence of flexural stiffness on DRPW and proposed an optimization method, namely, variable stiffness technology. Two optimal types of DRPW, namely DRPW with enlarged section of FR and that with enlarged section of RR, were compared to the traditional equal-section DRPW. The effects of flexural stiffness ratio, excavation depth, and surcharge loading were investigated in this study using physical scale test and finite-difference method. The model piles were instrumented with strain gauges and dial meters to measure the bending moment and deflection, respectively. The three types of DRPW have the same volume, height, sum of cross-section area, and material. Favorable consistency was observed between the numerical simulation and model test. Overall, the flexural rigidity ratio of FR to RR has a remarkably impact on the mechanical property of DRPW; thus, increasing the stiffness of the front pile is effective. The three types of pile arrangement are ranked as follows: the DRPW with enlarged section of front pile > the DRPW with enlarged section of rear pile > the traditional equal-section DRPW.

摘要

双排桩墙（DRPW）的传统桩设计方法偶尔会考虑前排（FR）与后排（RR）之间的抗弯刚度比的影响。DRPW 已不能满足较大挖掘深度的沉降变形要求。本研究评估了抗弯刚度对 DRPW 的影响，并提出了一种优化方法，即变刚度技术。与传统的等截面 DRPW 相比，两种最佳类型的 DRPW，即 FR 截面扩大的 DRPW 和 RR 截面扩大的 DRPW。本研究采用物理尺度试验和有限差分法研究了抗弯刚度比、开挖深度和超载荷载的影响。模型桩配备应变仪和千分表来测量弯矩和挠度，分别。三种类型的 DRPW 具有相同的体积、高度、横截面积和和材料。在数值模拟和模型试验之间观察到了良好的一致性。总体而言，FR与RR的抗弯刚度比对DRPW的力学性能有显着影响；因此，增加前桩的刚度是有效的。三种排桩方式依次为：前桩加大断面DRPW>后桩加大断面DRPW>传统等截面DRPW。因此，增加前桩的刚度是有效的。三种排桩方式依次为：前桩加大断面DRPW>后桩加大断面DRPW>传统等截面DRPW。因此，增加前桩的刚度是有效的。三种排桩方式依次为：前桩加大断面DRPW>后桩加大断面DRPW>传统等截面DRPW。