非线性接触力学模型在地基-基础相互作用弹性分析中的应用

Elastic analysis for soil-foundation interaction by using a nonlinear contact force element model

针对多体相互作用体系的非连续变形分析问题和接触问题,采用 Mohr-Coulomb 屈服准则和关联流动法则以及接触界面上的非线性应力分布模式,考虑接触界面特性提出了非线性接触力元模型,以结点位移和界面相互接触应力同时作为独立未知变量,建立了离散系统的总体控制方程。进而,通过数值求解能够直接确定变形体内的应力与变形、界面上的接触应力与离散体的位移与运动。将这种以接触力元为基础的多体系统分析方法具体应用于基础与地基相互作用分析,通过数值计算与分析探讨了地基与基础的相对刚度、荷载大小及其偏心距、地基与基础间界面力学参数对接触界面的应力分布和地基变形的影响,所得结果为工程中考虑基础与地基相互作用影响的设计与分析提供了参考依据。

For the contact problems and discontinuous deformation analysis problems of multi-bodies interaction system, a nonlinear contact force element model is developed. In the proposed model, the complex behavior of interface is taken account by using Mohr-Coulomb criterion and associated flow rule as well as a certain nonlinear distribution pattern of contact stresses along the interface. The nodal displacements and contact stresses of interface are simultaneously taken as the independent unknowns and the resulting governing equations are formulated for the discrete system. Then the numerical formulations are established and implemented for directly solving for the stresses and deformations of the continuous media and interaction stresses and relative displacements as well as the movements of the discrete bodies. Then the numerical procedure based on the proposed nonlinear contactforce element is applied for elastic analyses of soil-foundation interaction. Through numerical computations, the effects of the relative rigidity of soil and foundation, load amplitude and eccentricity, mechanical parameters of interfaces on the soil-foundation interaction behavior are systematically examined. The computed results will be instructive for consideration of soil-foundation interaction effect in engineering design and analysis.