被动桩与土相互作用解析计算研究
Analytical solution to interaction between passive piles and soils
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摘要: 为解决 被动桩 –土相互作用的力学问题,基于土体弹性假设及 Winkler 地基模型,分析了抗滑桩与土体相互作用机理,提出被动桩与土相互作用的弹性地基梁模型控制方程组,推导了桩身力学响应的数学解析表达式,编制 MATLAB 计算程序进行桩内力计算,并与现场监测数据进行了对比,结果验证了本文解析方法是可靠的;最后将该模型应用于深圳中荣煜滑坡治理的抗滑桩设计计算中,探讨了地基水平抗力系数,滑坡剩余推力及其分布函数,对抗滑桩内力和挠度的影响,计算结果表明:在滑坡剩余下滑力相同的条件下,各种不同分布形式中三角形分布将产生大的弯矩,抛物线分布次之,均匀分布最小,悬殊比率大,达 47% ;相同地基水平抗力条件下,均匀分布桩顶挠度大于三角形和抛物线分布;这些研究成果可为优化抗滑桩的结构设计及内力计算提供理论依据。Abstract: In order to analyze mechanical mechanism of passive pile-soil interaction in slope, based on the Winkler elastic model which assumes that soil displacement is elastic, a fourth-order differential equation considering passive pile-soil interaction is presented to describe the stabilizing pile subjected to an arbitrary profile of residual thrust, and the analytical solution is derived. The procedure is programmed with Matlab code. Meantime, the computed values are in good agreement with the in field monitoring data, which means that the suggested analytical solutions are reliable. Finally, the model is conducted in a case history of Shenzhen to verify the proposed analytical solution. The analysis is carried out to investigate the effects of subgrade modulus and distribution function of residual thrust on behavior of passive piles embedded in slope considering the interaction between passive piles and soils. The results show that the triangular distribution forms of residual trust will have the largest moment of passive piles, followed by a parabola, uniform distribution of the smallest. The relatively large gap can be up to 47%. Under the same level of subgrade modulus conditions, the uniform distribution of residual trust has large displacement of passive piles at the top around the piles than that of triangle and parabola distribution. The approach can provide theoretical helpful for calculating internal forces and displacements of stabilizing piles.