流体饱和两相多孔介质动力反应计算分析

基于流体饱和两相多孔介质的弹性波动方程组,运用显式逐步积分格式与局部透射人工边界相结合的时域显式有限元方法对该波动方程组进行求解,对两相介质在输入地震波作用下的弹性动力反应进行计算和分析;对在是否考虑孔隙流体渗流的两种情况下计算得到的两相介质弹性动力反应结果的差异进行对比研究,从而揭示孔隙流体渗流对两相介质动力反应性质的影响.计算结果表明:两相介质弹性动力反应时程的波形与入射地震波的波形相同,且弹性动力反应的峰值出现的时刻对应于入射地震波的峰值出现的时刻;孔隙流体的渗流将对两相介质的弹性动力反应性质产生显著的影响.数值计算同时表明,时域显式有限元方法是进行流体饱和两相多孔介质弹性动力反应计算分析的一种有效的方法.

Calculation and analysis of dynamic response of fluid-saturated porous media

The elastic wave equations of fluid-saturated porous media are solved by the time-domain explicit finite element method that consists of explicit step-by-step integral format and local transmitting artificial boundary. Then, the elastic dynamic response of fluid-saturated porous media under input earthquake wave is calculated and analyzed with the method mentioned above. At last, the calculating results of elastic dynamic response of fluid-saturated porous media are compared when the seepage of fluid in the cavity is taken account of or not in order to find out the effect of seepage of fluid in the cavity on the dynamic response property of porous media. Calculatiing results show that the figures of elastic dynamic response time history of porous media are same as the figures of input earthquake wave; and the time when the peak value of elastic dynamic response appears corresponds to the time when the peak value of input earthquake wave appears. The seepage of fluid in the cavity has a remarkable effect on the elastic dynamic response property of porous media. In the meanwhile, numerical calculations indicate that the time-domain explicit finite element method is effective for the calculation and analysis of the elastic dynamic response of fluid-saturated porous media.