基于T-P模型的桩-桩水平振动相互作用研究

为精确揭示桩-土动力相互作用,弥补动力Winkler地基-Bernoulli-Euler梁模型(E-W模型)在桩-桩水平振动分析中的不足。考虑土体剪切效应和桩身剪切变形,建立Pasternak-Timoshenko模型(T-P模型)模拟桩-土动力相互作用,推导水平动力和竖向荷载共同作用下的主动桩水平振动解析解。在此基础上,根据桩-桩动力相互作用原理,建立被动桩水平振动控制方程,运用传递矩阵法考虑土体分层特性,利用初参数法计算桩-桩动力相互作用因子;与已有文献进行对比,验证计算结果的正确性。通过参数分析表明：土体剪切效应对水平动力相互作用因子有增强效果;在给定桩土参数的情况下,主动桩和被动桩存在“有效桩长”(Ld=10d～15d);当桩身长径比在L/d=5～10范围内时,不宜忽略桩身剪切变形对动力相互作用因子的影响;竖向荷载对水平-摇摆耦合作用因子的影响最为显著。

RESEARCH ON PILE-PILE DYNAMIC INTERACTION OF LATERAL VIBRATION BASED ON T-P MODEL

To accurately reveal pile-soil dynamic interaction and remedy the shortcoming of dynamic Winkler foundation-Bernoulli-Euler beam model (E-W model), this paper considers soil shear effect and pile shear deformation, and establishes a dynamic Pasternak foundation-Timoshenko beam model (T-P model) to simulate pile-soil dynamic interaction. And the analytical solution for horizontal vibration of the active pile under horizontal dynamic and vertical load is derived. Based on this, the governing equations for horizontal vibration of the passive pile are established by the principle of pile-pile dynamic interaction. A transfer matrix method is used to consider the layered characteristics of soil, and an initial parameter method is utilized to calculate the pile-pile dynamic interaction factors. The correctness of the proposed method is validated by comparing the calculated results with existing solutions. Through the analysis of parameters, it is concluded that the shear effect of soil can enhance horizontal dynamic interaction factors. Given the parameters of pile and soil, there exists an effective pile length (L_d=10d~15d) for active and passive piles. When the length-diameter ratio of the pile is in the range of L/d=5~10, the influence of pile shear deformation on dynamic interaction factors should not be ignored. In addition, the vertical load has the most significant effect on cross-swaying-rocking dynamic interaction factor.