黏弹性流体饱和孔隙介质动力反应分析的显式有限元法

Dynamic Analysis of Fluid Saturated Porous Viscoelastic Media by Explicit Finite Element Method

黏弹性流体饱和多孔介质模型比单相介质或者弹性饱和孔隙介质更接近实际的土层介质,应用该模型研究土层介质的动力响应更为合理。用数值方法研究了半空间黏弹性流体饱和孔隙介质的动力时域响应。根据Biot黏弹性流体饱和两相多孔介质波动方程,采用解耦技术,建立了以固相位移和流相位移为未知量的黏弹性流体饱和孔隙介质动力分析的一种显式有限元法。该方法克服了隐式方法需要求解联立方程组的缺点,具有节省计算机内存空间和计算时间的优点。与解析解比较表明,该算法具有较高的计算精度;最后以一维黏弹性流体饱和孔隙介质为例,分析了黏性系数对动力响应的影响。

The fluid saturated porous viscoelastic media is closer to actual stratum than Blot media and single- phase media, and the researches on its dynamic response will be more reliable. A numerical investigation in the time domain of dynamic response on semi-infinite porous saturated vis^-oelastic medium is proposed. An explicit finite element method for dynamic analyses of fluid saturated porous viscoelastic medium was derived on the basis of the classical Biot＇s theory with uncoupling technical. Comparing with the conventional implicit methods which need to solve simultaneous equations, our algorithm has the advantages of saving computer memory and computing effort. It achieves satisfying accuracy in contrast with analytical methods. Taking one-dimensional fluid saturated viscoelastic porous medium as example, the influence of viscous coefficient on the dynamic responses has been investigated.