渗透作用下多孔介质中循环浓度污染物的迁移过程研究  

Contaminant transport under seeping condition in porous media with a contaminant source of cyclically variable concentration

作　　者：李华伟[1] 白冰[1] 王梦恕[1] 许韬[1] 

机构地区：[1]北京交通大学土木建筑工程学院,北京100044

出　　处：《岩土力学》2015年第5期1306-1312,共7页Rock and Soil Mechanics

基　　金：国家自然科学基金资助项目(No.51279002);国家自然科学基金资助项目(No.51478034);高等学校博士学科点专项科研基金博导类资助课题(No.20130009110021)

摘　　要：根据饱和多孔介质中考虑释放效应的一维渗透作用的可溶性污染物的迁移控制方程,通过Laplace变换和Fourier变换及其逆变换求得相应的通解形式。根据半无限体表面可溶性污染物点源注入情形下的基本解,通过积分方法得到半无限体表面圆形区域上作用循环浓度污染物后,在多孔介质内部污染物迁移过程的求解方法。作为一个典型算例,对渗透作用下循环浓度污染源引起的多孔介质中的迁移过程进行分析。算例表明,当污染源浓度为周期变化时,多孔介质内部污染物的浓度随时间增长由不稳定的周期变化过程逐渐过渡到稳定的循环过程,而某一深度处污染物浓度的相位则相应滞后。此时,稳定后的污染物浓度周期与污染源浓度周期相同。实际上,随多孔介质表面污染源浓度的周期变化,在靠近多孔介质表面一定深度范围内的污染物浓度在深度方向也呈增大或减小的交替变化过程。另一方面,在污染源循环变化过程中污染物不断向深处推进,而最终其影响范围限定在某一深度内。The governing equations for miscible contaminant transport in saturated porous media with release effect are developed under the I-D seepage condition, and an elementary solution is derived using the Laplace and Fourier transforms and their inverse transformation for the case of a point contaminant source which is instantaneously released from the surface of a half-space body. Then the analytical expression of the contaminant concentration in porous medium subjected to a circular contaminant source is derived from the elementary solution. A calculation example for cyclic contaminant source is analyzed. It is shown that the contaminant concentration in a porous medium varies in a cyclic manner under a cyclic contaminant source applied on the porous surface, and finally reaches a quasi-steady state with the same cyclic period as the contaminant source. However, the phase of concentration fluctuation at a given depth lags behind the contaminant source. At steady state, the cyclic period of contaminant concentration in the porous medium is the same as that of the contaminant source. In practice, as the contaminant source cyclically fluctuates at the surface of porous medium, the concentration of contaminant in a porous medium around the surface also increases or decreases alternately in the direction. On the other hand, the contaminant gradually penetrates towards depth and eventually reaches a definite depth away from the surface.

关 键 词：渗透作用 可溶性污染物 多孔介质 控制方程 循环污染源 

分 类 号：TU411[建筑科学—岩土工程]