局部土体地基的圆锥形黏弹性边界研究

Research for cone type spring-dashpot boundary condition of local soil foundation

当荷载施加于半空间土体地基的任意圆形自由表面上时,其产生的应力作用范围会随着深度的增加而呈一定比例的扩大。基于此,采用圆锥形黏弹性边界代替传统的圆杆性黏性边界条件来模拟半无限域土体地基是更为合理的。本文根据圆锥形黏弹性边界的基本理论建立的较容易实现的二维有限元求解方程,并分别对单一冲击波在圆锥形黏弹性边界和圆杆形黏性边界的局部域土体地基及无限域土体地基中传播进行分析。结果表明,圆锥形边界局部域地基与无限域地基的位移响应更为一致;因此,圆锥形黏弹性边界在吸收波的反射较传统的圆杆形黏性边界条件更有优势,且更接近波在土体地基中传播的真实本质。

When a load is applied to the disk on the free surface of a half space,stresses act on an area that increases with depth due to geometric spreading. Therefore,using cone type local non-reflecting boundary condition modeling semi-infinite soil domain is more reasonable than rod model from which viscous boundary condition can be derived. The cone type boundary condition compares to the other traditional boundary conditions for absorbing the spurious wave reflections in the paper. The displacement response of soil domain free surface of cone type non-reflecting boundary condition has produced results essentially in agreement with those of infinite domain foundation.This is enough to explain the suitability and efficiency of the cone the cone type spring-dashpot boundary condition compared to the rod viscous boundary conditions.