重力式地下孔灌土壤水分运动规律试验研究

设计了一种重力式地下孔灌系统,具有集雨和灌溉双重功能.通过室内土箱试验,研究了不同压力水头、竖管孔径和埋深条件下土壤水分运动规律.结果表明:Philip入渗模型能够较好地描述重力式地下孔灌土壤入渗过程,决定系数大于0.99;累积入渗量随压力水头和竖管孔径的增大而增大,竖管埋深对其影响微弱;幂函数能够较好地描述湿润锋运移过程,湿润锋运移距离呈现出垂直向下大于水平方向、水平方向大于垂直向上的规律;三个方向上的湿润锋运移距离与压力水头和竖管孔径呈正相关,竖管埋深对其影响较小.重力式地下孔灌土壤入渗主要受压力水头、竖管孔径等因素的影响.

Experimental investigation of movement regularity of soil moisture during gravity-type underground hole irrigation

A system of gravity-type underground hole irrigation is designed, which has double functions of rainwater collection and irrigation. Through indoor soil box test, the movement regularity of soil moisture is investigated under condition of different pressure head, hole diameter on vertical tube, and its cover-up depth. The result shows that its infiltration process can be well described by Philip infiltration model and it is found that the decision coefficient will be greater than 0.99 and the cumulative infiltration will increase with the pressure head and hole diameter. The cover-up depth of vertical tube will have slight influence on it. The wetting front movement process can be well described with power function and the wetting front movement distance will assume such a variation regularity that vertical downward movement distant will greater than horizontal one and horizontal one will greater than vertical upward one. There will be a positive correlation between the wetting front movement distance in these three directions and the pressure head and hole diameter, however, will have slight influence on the cover-up depth of the vertical tube. The infiltration of soil moisture ofgravity-type underground hole irrigation will be mainly affected by the factors such as pressure head and hole diameter.