考虑源汇项的1维稳态流下非饱和土基质吸力的解析解

Analytical Solution to the Matric Suction of Unsaturated Soil by a Source Term's 1D Steady Flow

根据1维稳态渗流微分方程,结合Gardner模型,求解考虑源汇项的均质非饱和土基质吸力铅直分布通解,并据此求解不考虑源汇项和源汇项为非零常数两种情形下基质吸力铅直分布的特解。通过算例计算对比有源汇项蒸发、无源汇项蒸发、静水条件、有源汇项入渗和无源汇项入渗等5种情况下非饱和粉土层内基质吸力铅直分布规律。结果表明:源汇项为非零常数时,基质吸力铅直分布受土层表面比流量、源汇项,饱和渗透系数等因素控制;在静水条件下,基质吸力与距地下水位的距离呈线性关系;在非静水条件下,呈非线性关系。源汇项为非零常数且与流动方向同号时,比流量自地下水位处至地表递增。当地表比流量相同时,在蒸发条件下,基质吸力比无源汇项的相应条件下的基质吸力要小;在入渗条件下,则相反。

To ascertain the vertical distribution of the matric suction in unsaturated soil by a source term＇ s 1 D steady flow, a general solution was found with Gardner model. In addition, two particular solutions under the conditions of no source term and constant source term were also obtained,and the vertical ,distribution of the matric suction in unsaturated silt soil was analyzed under different surface flux boundary conditions and by different source terms. The results showed that the matnc s^ctlon4n unsaturated silt soil,when adopting constant source term, could be controlled with a specific discharge from the surface, a source term, a soil-saturated infiltration coefficient and others. Under hydrostatic conditions ,the matric suction and the distance from water table had a linear relationship. However,the re-lationship was non-linear in non-hydrostatic conditions. The specific discharge, when applying the constant source terms in the same di-rection of water flow,increased from the groundwater level to surface. Under the condition of evaporation, the matric suction by a con-stant source term was less than that with no source term at the same surface flow rate, whereas the result was the reverse when in the in-filtration conditions.