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将地震液化场地分为地表的上覆未液化土层、底部的未液化基层以及夹在两者之间的液化土层,基于桩-土相互作用的非线性Winkler模型,考虑桩弯曲的非线性弯矩-曲率本构关系和桩的几何非线性变形,建立了液化土层横向扩展下桩非线性大挠度变形的基本控制方程,并利用打靶法进行了数值求解。同时,给出了桩线弹性小变形情形下的解析解。通过与非线性有限元解和线弹性小变形解析解的比较,验证了文中打靶法的有效性和可靠性。用数值方法分析了液化土层横向扩展对桩力学性能的影响,结果表明:非线性桩-土相互作用和桩材料非线性效应强于桩的几何非线性效应,随着液化土层横向扩展位移的增加,几何非线性效应逐渐增大,此时,应采用完全非线性模型进行桩力学行为的分析。
Based on the nonlinear Winkler model of pile-soil interaction, the seismic liquefaction site is divided into the upper unliquidified soil layer on the ground surface, the unhydrated base layer on the bottom and the liquefied soil layer sandwiched between them. Considering the nonlinearity of pile bending Bending moment-curvature constitutive relationship and geometrical non-linear deformation of piles, a basic governing equation of nonlinear large deflection deformation under liquefied soil horizontal spreading is established, and numerical simulation is conducted by using shooting method. At the same time, an analytical solution is given for small elastic deformation of pile. By comparing with the nonlinear finite element solution and linear elastic deformation analysis solution, the validity and reliability of the shooting method in the text are verified. The results show that the nonlinear pile-soil interaction and pile material nonlinear effect are stronger than the pile’s geometric nonlinear effect. With the lateral expansion of liquefied soil layer displacement , The geometric nonlinear effect gradually increases. At this moment, the complete nonlinear model should be used to analyze the pile mechanics behavior.