轴向荷载作用下单桩沉降的非线性分析

将单桩简化为受侧摩阻力的弹性杆单元,土体简化为均质弹性半空间无限体.以桩顶荷载作用下桩单元的变形、结点位移及结点力作为中间变量,依据弹性半空间无限体的Mindlin解以及桩-土相对滑动的性质,建立了土体的位移方程、接触面的平衡方程,并以此构造了以结点位移为基本未知量的非线性方程组.求解包含桩顶位移在内的各结点位移后,可进一步计算单桩及接触面的内力、土体的位移等.考虑了桩-土相对滑动及桩底沉降的非线性性质,所建立的桩-土体系分析模型力学机理简单、明确,便于应用,分析结果与试验结果较为符合.

NONLINEAR ANALYSIS OF SETTLEMENT OF AXIALLY LOADED VERTICAL PILES

The single pile is simplified to elastic shaft elements suffering skin friction and the soil mass is considered to be homogeneous isotropic elastic semi space. For pile loaded on the head, treating deformation of pile elements, node displacements and node forces of the pile as intermediate variables, displacement equations of soil mass and equilibrium equation of pile-soil contact surface are established based on Mindlin equation and characters of relative slipping between pile and soil. Regarding node displacements as basic unknown quantities, the two sets of equations are combined into a system of equations. When node displacements including settlement of pile head are calculated, internal force of pile, contact surface and displacement of soil, etc., can be calculated. Nonlinear relative slipping between pile and soil and nonlinear settlement of pile base soil are considered. Mechanism of the model is simple and clear. The analytical results agree with the test results well.