挡土墙地震反应非线性波动模拟

Nonlinear wave propagation simulation of seismic response of retaining wall

本文运用解耦近场非线性波动数值模拟方法研究挡土墙地震反应,为反映墙土体系在地震作用下的位移机制,引入了Desai薄层单元模拟墙土间接触面,并采用双线型本构关系作为接触面单元和土体的非线性模型,在此基础上给出了解决P-SV问题的非线性显式有限元时域递推公式,为进一步发展非线性波动数值模拟技术提供了有益经验。为验证本文方法及适用性,将数值模拟结果与Zeng,X.和Madabhushi,S.P.G.等的离心机试验和弹塑性数值模拟结果进行对比。结果表明:墙土体系加速度、挡土墙顶底相对滑移、沉降和墙体倾角等同离心机试验模拟结果基本吻合,与弹塑性数值模拟结果相似。

Decoupling methods for numerical simulating nonlinear wave propagation of near field are developed for study on seismic response of retaining wall. Desai thin-layer elements imitating interface of retaining wall and backfill are inducted, and bi-linear constitutive relations are introduced as nonlinear constitutive relations of soil elements and interface elements in order to consider permanent displacement. Based on these models, two-dimensional (P-SV) lumped mass nonlinear explicit finite element formulas are brought forth in time domain, which might provide some experience for further study. To verify reliability of this method and its applicability, results of centrifuge experiment and elasto-plastic numerical simulation, obtained by Zeng, X. and Madabhushi, S. P. G. et al. are compared with those of this paper. Calculated acceleration response of wall and soil, relative displacement between the top and the bottom, settlement, inclination angel of retaining wall, etc. are in agreement with those of centrifuge test, and similar to those of elasto-plastic numerical simulation.