摘要
基于Biot流体饱和多孔介质理论,求得层状饱和地基表面移动荷载的动力格林函数,进而建立2.5维间接边界元方法,研究了高速移动列车荷载作用下层状饱和地基-轨道耦合系统的动力响应。该文通过与已有结果的比较验证了方法的正确性,并以均匀饱和半空间地基和饱和基岩上单一饱和土层地基为模型进行了数值计算,分析了列车移动速度和饱和土层等对动力响应的影响。研究表明,层状饱和地基和均匀饱和地基对应的动力响应有着显著的差别;列车移动速度接近饱和地基的Rayleigh波速时,会引起饱和地基-轨道耦合系统的共振,产生较大的动力响应;饱和地基不透水情况下动力响应最大,饱和地基透水情况下动力响应次之,干土情况下动力响应最小。另外,饱和土孔隙率、饱和基岩与饱和土层刚度比、饱和土层厚度等也对动力响应具有重要影响。
Based on the Biot＇s theory of two-phased poroelasticity medium, the dynamic Green＇s functions of a layered saturated half-space under surface moving loads are derived, and then the 2.5D indirect boundary element method is proposed to study the dynamic response of the coupled system of track and layered fluid-saturatedground under high-speed moving loads. The method is verified by comparisons with those in literatures. Numerical calculations are performed by taking uniform saturated ground and a single saturated layer over a saturated half-space as models and the effects of moving velocities and of the saturated layer on the dynamic response are analyzed. It is shown that： the dynamic response of a coupled system in the case of layered saturated ground is essentially different from that in the case of uniform saturated ground; when the train speed approaches the Rayleigh velocities of sites, the resonance of the coupled system takes place, which results in a large dynamic response and significant pore pressure; the dynamic response of a coupled system is the largest in the case of undrained conditions, the second in the case of drained conditions and the lowest in the case of dry conditions. The porosity of a saturated layer, the stiffness ratio of bedrock to the saturated layer, and the thickness of the saturated layer all have significant influences on the dynamic response.
出处
《工程力学》
EI
CSCD
北大核心
2015年第11期189-200,共12页
Engineering Mechanics
基金
天津市应用基础及前沿技术研究计划项目(12JCQNJC04700)
关键词
层状饱和地基-轨道耦合系统
层状饱和地基
移动荷载
土层动力特性
2.5维间接边界元
动力响应
coupled system of track and layered fluid-saturated ground
layered fluid-saturated ground
moving load
dynamic characteristics of layered ground
2.5D indirect boundary element method
dynamic response
