含水层和土壤的随机特征对水分运动的影响

将土壤或含水层的介质参数视为随机分布,建立了饱和非饱和水流运动的随机微分方程,利用随机数值求解方法,得到各种随机参数对水头分布和含水量空间变异性的影响。分析结果表明,随着渗透系数空间变异性和相关尺度的增大,含水层水头分布的变异性增大;对于区域内有抽水井分布的问题,在井点附近区域,z向水流速度空间变异性大,而在井点处变异性较小。当采用Gardner-Russo模型描述非饱和水分特征时,其非饱和土壤介质参数α的变异性对土壤负压和含水量变异性的影响大于饱和渗透系数,土壤含水量越小,含水量的空间变异性越大。初步讨论了根据随机数值方法研究地下水运动问题的可靠性分析方法。

Effect of random characteristics of soil and aquifer on the water flow in formations

A stochastic partial differential equation of water flow in saturated unsaturated formations is developed with the soil and aquifer conductivities treated as the random fields.The variability of water head resulting from the random roil parameters are analyaed based on the stochastic numerical rmdel.It is shown that the water head variability increases with the increasing soil parameter variability and its correlation length.The variability of water velocity is large in:direction and small at the pumping point when there is a pumping well in the simulation domain.The unsaturated parameter a in the Gardner model has larger effect on the variability of pressure head and water content than the saturated conductivity of the soil.The simulation resups indicate that the smaller the water content,the larger the variability of water content.The application of the stochastic numerical model to the analysis of the reliability of groundwater flow is also discussed.