地铁移动荷载作用下地基沉降的弹塑性分析

Elastic-plastic Analysis of Foundation Settlement Caused by Subway Moving Load

土体本构、隧道-地基模型与地铁荷载模拟是长期地铁移动荷载作用下地基土沉降研究的三个关键因素。本文以Drucker-Prager塑性本构模型表示土体应力-应变关系,采用与不平顺管理标准相应的激振力来模拟列车竖向动荷载,使用FLAC3D软件建立了地基结构的空间模型,详细探讨地铁隧道地基土沉降在不同加载次数下的动力反应和沉降规律。研究结果表明:埋深对地基土沉降的影响明显,随着埋深的减少,地基土的沉降逐渐增加;对于长期动荷载作用下的地基变形问题,采用塑性本构模型更能符合实际工况。

The soil constitutive model, tunnel-foundation model and simulation of the subway load are three critical factors of the foundation settlement problems caused by long-time subway moving load. In his paper, the Drucker-Prager model, a plastic constitutive model was adopted to represent the stress strain relationship of soil. The exciting force corresponding to the unsmooth management standard was adopted to simulate the vertical subway load. Spatial model of foundation structure was established using FLAC3 D software. Then a detailed analysis was performed on the dynamic response of the foundation that subjected to subway load with different running times. The results show that buried depth of strata have great influence on the foundation settlement, the foundation settlement increases gradually with the reducing buried depth. For the foundation deformation caused by long-term moving load, the plastic constitutive model is more appropriate for describing irrecoverable, long-time and cumulative foundation settlement.