SH波作用下液化土中桩-土-上部结构的动力相互作用  

DYNAMIC INTERACTION OF PILE-SOIL-SUPERSTRUCTURE IN LIQUEFIED SOIL UNDER SH WAVE

作　　者：杨骁[1] 方晓雯[1] 汪德江[1] 

机构地区：[1]上海大学土木工程系,上海200072

出　　处：《工程力学》2017年第1期101-108,共8页Engineering Mechanics

摘　　要：以桩-土相互作用的Winkler模型为基础,将桩等效为Timoshenko梁,上部结构等效为刚性质量块,研究了桩基底土体承受垂直入射简谐SH波作用的液化土层中桩-土-上部结构系统的动力特性。考虑土体的自由场位移以及上部结构质量、转动惯量和桩轴向压力的二阶效应,建立了液化土层中单桩-土-刚性上部结构系统的边值问题,并利用分离变量法得到桩变形的解析解。在验证理论模型和解析解合理性和有效性的基础上,分析了几何和物理参数等对桩头位移放大因子和动力放大因子的影响,研究结果表明:单桩-土-上部刚性结构系统存在明显的共振现象,且土体自由场位移对桩头位移放大因子影响显著。随着土体液化程度的发展,单桩-土-刚性上部结构系统基频、桩头动力放大因子和桩失稳临界荷载逐渐减小。Based on the Winkler model for pile-soil interaction, and regarding the pile as a Timoshenko beam and the superstructure as a rigid mass body, the dynamic characteristics of pile-soil-superstructure systems in liquefied soil layers subjected to vertical incident harmonic SH waves from the soil at the pile bottom are investigated. The boundary value problem of the single pile-soil-rigid superstructure system is established, in which the free-field displacement of the soil, mass and inertia moment of rigid superstructure and the second order effect of the axial pressure of the pile are taken into consideration. The analytical solution of the pile deformation is derived by using the separation of variables. On the basis of the verifications of justification, validity of the theoretical model and analytical solution, the influence of the geometry and physical parameters on the displacement amplification factor and dynamic amplification factor at the pile top are analyzed. The result shows an evident resonance phenomenon in the single pile-soil-rigid superstructure system, and the influence of the free-field displacement of the soil on the displacement amplification factor at the pile top is remarkable. Furthermore, with the development of soil liquefaction degree, the fundamental frequency, dynamic amplification factor at the pile top and the critical load of the pile of the single pile-soil-rigid superstructure system decrease.

关 键 词：SH波 液化土 桩-土-结构相互作用 WINKLER模型 动力特性 解析解 

分 类 号：TU473.1[建筑科学—结构工程] TU470[建筑科学—土工工程]