Modeling the dynamics of seal formation and its effect on infiltration as related to soil and rainfall characteristics
Modeling the dynamics of seal formation and its effect on infiltration as related to soil and rainfall characteristics
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DOI：
10.1029/96wr02674
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发表时间：
1997-07-01
影响因子：
5.4
通讯作者：
Mualem, Y
中科院分区：
文献类型：
--
作者：
Assouline, S;Mualem, Y
模拟了降雨引起的土壤表面密封形成的主要物理方面。所提出的模型涉及的表面密封的初始原状土壤的特定的水力和机械性能，以及施加的降雨的物理特性，在给定的初始和边界条件下定义的流系统。雨滴冲击引起的土壤扰动表现为初始土壤容重的增加。密封形成在土壤表面的动力学被认为是与以下变量：降雨强度，第二时刻的滴大小的密度分布，最大滴直径，给定土壤的压实极限，其初始剪切强度，这取决于初始土壤的容重和含水量。根据Mualem和Assouline [1989]，考虑了非均匀密封，其表现为体积密度随深度呈指数递减的函数。假设密封厚度取决于降雨率。它的稳定状态值被假定为在降雨开始后不久达到，以便它可以被认为是恒定的形成阶段。一个校准程序的基础上测得的渗透密封条件下。结果表明，该模型解决了影响土壤密封形成的主要因素，能够模拟饱和和非饱和流条件下的渗透过程中通过密封土壤。
The main physical aspects of soil surface seal formation caused by rainfall are modeled. The proposed model relates the surface sealing to the specific hydraulic and mechanical properties of the initially undisturbed soil as well as the physical characteristics of the rainfall applied, under given initial and boundary conditions defining the flow system. The soil disturbance resulting from the raindrop impacts is expressed in terms of an increase of the initial soil bulk density. The dynamics of seal formation at the soil surface are found to be related to the following variables: the rainfall intensity, the second moment of the drop-size density distribution, the maximal drop diameter, the compaction limit of the given soil, and its initial shear strength, which depends upon the initial soil bulk density and water content. Following Mualem and Assouline [1989], a nonuniform seal is considered, represented by an exponentially decreasing function of the bulk density with depth. The seal thickness is assumed to be dependent upon the rainfall rate. Its steady state value is assumed to be reached shortly after the beginning of rainfall so that it might be considered as constant during the stage of formation. A calibration procedure is presented on the basis of measured infiltration under sealing conditions. The results show that the proposed model addresses the main factors affecting soil sealing formation and is able to simulate the process of infiltration through sealing soils under saturated as well as unsaturated flow conditions.