基于增量迭代法的深基坑桩锚支护结构位移计算简化方法

针对深基坑桩锚支护结构工程的施工特点,提出采用增量法对深基坑桩锚支护结构进行设计研究,把深基坑因开挖引起的桩体位移这一非线性问题用近似的线性方法解决,用一系列线性的分段折线去代替非线性曲线.考虑到基坑开挖过程中桩锚支护结构位移的影响,推导出基于桩体位移的土压力模型的位移计算公式,再运用迭代法对每步求出的桩体位移量进行修正,避免增量法计算产生的误差累计叠加.结合工程实例,把上述方法用Matlab编制成计算程序,将计算结果与有限元模拟软件Plaxis的模拟结果以及常规增量法对比分析,结果表明,用提出的简化方法计算桩体位移更加接近工程实际,较常规增量法更为准确.

Simplified method to calculate displacement of the pile anchor protect structure of deep excavation based on the incremental iteration method

According to construction characteristics of deep foundation pile anchor retaining structure engineering, an incremental method to design and investigate the deep foundation pile anchor retaining structureis proposed.The nonlinear problem of pile displacement caused by excavation is solved approximately by the linear method, namely, the nonlinear curves are replaced by a series of segmented linear lines. By taking into account the influence of displacement of pile anchor retaining structure during excavation of the base pit, a displacement calculation formula for the soil pressure model based on the pile displacement has been derived. Then the pile displacement calculated in each step is revised by an iterative method, so as to avoid the error accumulation caused by incremental method. Combined with an engineering example, the above proposed method is programmed with MATLAB, and corresponding calculated results are compared directly with those predicted by both finite element simulation software PLAXIS and the conventional incremental method, the correctness and rationality of the method are verified.The proposed simplified method is closer to engineering practice and predictions by the method are more accurate than those by conventional incremental method.