郭文胜1, 魏艳卿2, 姜平远2
考虑刚性桩复合地基影响的主动土压力强度计算方法研究
郭文胜1, 魏艳卿2, 姜平远2
摘 要:针对坑外邻近刚性桩复合地基条件下侧向土压力的计算,规范采用的是朗肯土压力作图法按天然地基计算,未能考虑桩体的荷载传递效应及附加应力随深度的变化。基于桩侧摩阻力分布假设,采用Mindlin解和Boussinesq解分别求得桩体与桩间土产生的竖向附加应力,并结合Mohr-Coulomb强度准则,依据极限平衡法推导出既有刚性桩复合地基条件下主动土压力强度计算公式,并将本文算法与规范算法和朗肯主动土压力进行对比分析。结果表明,本文计算土压力强度分布大于朗肯主动土压力而远小于规范计算值,并随深度呈非线性分布,桩体的荷载传递效应会对桩端附近土体产生附加土压力,0.5倍桩长范围内仅考虑桩间土的附加土压力。最后,通过室内模型试验结果与本文计算结果进行对比,证明了所提算法的合理性与有效性。
Abstract: The Rankin’s active pressure calculated method of the standard under the condition of natural foundation is used to compute the lateral earth pressure adjacent to rigid pile composite foundation. It ignores the deep transfer function of pile load and the change of additional stress along depth. Based on the assumption of the lateral frictional resistance distribution, this paper combined M-C criterion and limit equilibrium method, use Mindlin solution and Boussinesq solution to calculate the vertical additional stress between piles and soil, meanwhile, the active earth pressure adjacent to rigid pile composite foundation is computed. This method is compared with the standard method and the Rankin’s active pressure. The results showed that the active pressure intensity is smaller than that is calculated by standard, and the distribution curve is nonlinear. At the same time, the active pressure intensity of pile tip is influenced by the transfer function of pile load, and with the scope of the 0.5 times of pile length only considers the influence of vertical addition stress of soil between piles. Finally, comparing the result of the indoor model test and calculation method in this article can verify the rationality and effectiveness of this method.
版权所有:中国混凝土与水泥制品网 苏ICP备10086386号 网站建设:中企动力 苏州