基于集中质量体系的侧向自由场边界

Lateral Free Field Boundary Based on Centralized Mass System

以土-结构动力相互作用模型的侧向人工边界为研究对象,从理论上对非对称矩阵和对称矩阵形式下的自由场边界进行分析,将集中质量体系和黏性元件或黏弹性元件组合在一起,形成集中质量自由场边界.然后设置典型算例,采用有限元软件ABAQUS,把剪切波从底部垂直入射,对均匀场地、分层场地和含地下结构场地下集中质量自由场有效性进行验证.最后设置不同土体阻尼比和不同结构宽高比情况,对集中质量自由场边界与黏弹性边界和滚轴边界的精度进行对比.结果表明,同等情况下在工程应用中集中质量自由场边界的精度合理,且操作简便.

The lateral artificial boundary of the soil-structure dynamic interaction model was selected as research object,the free field boundary was theoretically analyzed in asymmetric-and symmetric-matrix forms.The lumped mass system was combined with viscous or viscoelastic elements to obtain a lumped mass-free field boundary.Then,typical examples were implemented using the finite element software ABAQUS.The shear wave was incident perpendicularly from the bottom to verify the effectiveness of the lumped mass-free field under various sites:uniform structures,layered sites,and underground sites.Finally,the accuracy of the lumped mass-free field boundary was compared with those of the viscoelastic and roller boundary on different width-to-height ratios and soil damping ratios.The results show that the precision of the lumped mass-free field boundary was reasonable and the operation was simple in the same engineering application.