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为了解深基坑桩锚支护结构的工作性能,考虑到桩、锚索和土相互作用的情况下,采用FLAC3D对桩锚支护结构在不同工况下受力特性进行了模拟与研究,本文仅讨论桩的受力变化规律。研究表明:随着基坑开挖深度的增加,桩身轴力值、剪力值逐渐增加,在基坑底面处达到最大;不同的桩长度、锚索长度及预应力值大小对桩身轴力、剪力值的变化影响较小;桩身刚度存在一个最佳值,无限度增加和减小桩身刚度分别会造成经济浪费和不安全因素。所得变化规律曲线与现场试验、理论计算得到的桩内力变化曲线形式和发展趋势相吻合,进一步解释了桩锚支护结构中桩与土的相互作用机理,为桩锚支护优化设计提供一些参考。
In order to understand the working performance of pile-anchor supporting structure of deep foundation pit, considering the interaction between pile, anchor cable and soil, the dynamic characteristics of pile-anchor supporting structure under different working conditions were simulated and studied by FLAC3D. This article only discusses the force variation of pile. The results show that with the increase of excavation depth, the values of axial force and shear force of pile body increase gradually and reach the maximum at the bottom of foundation pit. Different pile lengths, lengths of anchor cables and prestress values affect pile shaft Force and shear force have little effect on the change of the pile’s stiffness. There exists an optimum value of the pile’s stiffness, which will cause economic waste and insecurity if the pile’s stiffness is increased and decreased indefinitely. The curve of the obtained variation is consistent with the field test and theoretical calculation of the curve and development trend of pile internal force, which further explains the interaction mechanism between pile and soil in the pile-anchor supporting structure and provides some references for the optimization design of pile-anchor supporting .