An approximate spring–dashpot artificial boundary for transient wave analysis of fluid-saturated porous media
An approximate spring–dashpot artificial boundary for transient wave analysis of fluid-saturated porous media
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DOI：
10.1016/j.compgeo.2008.01.008
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发表时间：
2009
影响因子：
5.3
通讯作者：
Zi-Hao Wang;Cheng-gang Zhao;Liang Dong
中科院分区：
文献类型：
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作者：
Zi-Hao Wang;Cheng-gang Zhao;Liang Dong
实际土木工程问题通常是在无限半空间域中表述的，用有限元法分析饱和流体多孔介质的动力响应时，需要选定一个有限域。设计一种处理有限域边界的方法是该开放系统的关键问题。本文建立了一种用于饱和流体多孔介质瞬态分析的二维弹簧-阻尼人工边界（SDAB）。基于Biot流体饱和多孔介质动力学理论，推导出圆柱体波的法向和切向边界应力公式。边界应力与位移和速度成正比，因此可以在法向和切向的人工边界上放置连续分布的阻尼器和弹簧，模拟有限域外无限介质对内部分布源问题的能量吸收。对于外部分布震源的地震散射问题，本文通过在SDAB上施加等效荷载来实现输入地震运动。给出了数值算例，分析结果表明，SDAB和波动输入方法具有良好的稳定性和可接受的精度。
Practical civil engineering problems are usually formulated in an infinite half-space domain, and a selected finite domain is required to analyze the dynamic responses of a fluid-saturated porous medium by the finite element method (FEM). Devising a method to deal with the boundaries of the finite domain is the key issue for this open system. In this paper, a two-dimensional spring–dashpot artificial boundary (SDAB) for transient analysis in a fluid-saturated porous media is developed. Based on Biot’s dynamic theory of fluid-saturated porous media, the normal and tangential boundary stress formulae are deduced for out-going cylindrical body waves. The boundary stress is proportional to displacement and velocity, thus continuously distributed dashpots and springs can be placed on the artificial boundaries in the normal and tangential directions to simulate the energy absorption of the infinite media outside of the finite domain for the interior distributed source problems. In this paper, the input seismic motion can be realized by applying an equivalent load on the SDAB for the seismic scattering problems of exterior distributed sources. Numerical examples are given and the analyzed results show that the SDAB and the method of wave motion input have good stability and acceptable accuracy.