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该文基于文克尔地基梁理论,利用修正的P-Y曲线法和荷载传递双曲线法,建立了桩-土非线性作用模型。采用了桩和土相对刚度来计算水平方向桩-土相互作用的初始刚度。通过Mohr-Coulomb法则得到土的极限抗力,并结合Matlock P-Y曲线法对极限抗力的表达式进行了修正,从而充分考虑了土的极限抗力的深度效应。编制了桩-土非线性梁单元有限元程序,建立了考虑非线性桩-土相互作用的车桥耦合模型。结合工程实例,分析了非线性桩-土相互作用的桥梁模型对车桥耦合响应的影响,并与墩底固结模型进行了对比。结果表明:在车桥耦合振动过程中,考虑非线性的桩-土相互作用,桥梁的横向位移幅值显著增大,竖向位移幅值增大,桥梁加速度幅值降低。此结果对处于软弱基础的高速铁路桥梁的分析和设计提供了参数和依据。
Based on the Wenkeel foundation beam theory, a nonlinear model of pile-soil interaction is established by the modified P-Y curve method and load transfer hyperbola method. The initial stiffness of the horizontal pile-soil interaction is calculated using the relative stiffness of pile and soil. Through the Mohr-Coulomb law, the ultimate resistance of the soil is obtained, and the expression of the ultimate resistance is corrected by the Matlock P-Y curve method, so that the depth effect of the ultimate resistance of the soil is fully taken into account. The finite element program of pile-soil nonlinear beam element is established, and a vehicle-bridge coupling model considering nonlinear pile-soil interaction is established. Combined with engineering examples, the effect of the bridge model with nonlinear pile-soil interaction on the axle-axle coupling response is analyzed and compared with the pier-bottom consolidation model. The results show that in the process of vehicle-bridge coupling vibration, considering the nonlinear pile-soil interaction, the lateral displacement amplitude of the bridge increases significantly, the amplitude of vertical displacement increases, and the amplitude of bridge acceleration decreases. This result provides the parameters and basis for the analysis and design of high-speed railway bridges on a weak foundation.