传统降雨入渗分析是以降雨强度在坡面上的正交分量作为边界条件，不符合实际降雨的非正交入渗规律。为了研究非饱和粉质黏土的非正交入渗规律性，首先通过对正交入渗理论的综述，揭示并分析目前降雨入渗理论在坡面流模型和边界条件方面的缺陷。采用自行研制的室内降雨试验装置对非饱和粉质黏土进行不同降雨强度、坡角和孔隙比的降雨入渗试验，结果表明，非饱和粉质黏土坡面降雨入渗是并非简单正交分解入渗而是非正交入渗；对于坡角和孔隙比为定值的土坡，具有最大坡面入渗的最优雨强；土的孔隙比越小，降雨初期入渗率随时间变化越快，入渗率趋于稳定状态越快；入渗率和累积入渗量并不是随坡角的增大呈单调变化，而存在对应入渗水量最少的最优坡角。

The traditional rainfall infiltration boundary, decomposing the rainfall intensity according to the slope direction, does not conform to the actual non-orthogonal rainfall infiltration. Firstly, for the purpose of studying the rules of non-orthogonal rainfall infiltration on the unsaturated silty clay slopes, the defects of the slope infiltration models and boundary conditions now available were revealed and analyzed by the review of infiltration theories. Secondly, the infiltration tests of unsaturated silt clay slopes under different rainfall intensities, slope angles, and void ratios were carried out by designing an artificial rainfall device. The test results indicate that the rainfall infiltration on surfaces of unsaturated silt clay slopes is non-orthogonal infiltration rather than simply decomposed orthogonal infiltration; for a given soil slope with a definite angle of and a void ratio, there exists an optimum rainfall intensity at which the maximum infiltration can be achieved; the smaller the void ratio is, the faster the infiltration rate changes at the beginning stage of a rainfall and quicker to come to its stable state. There is an optimum slope angle at wich the amount of infiltration is the smallest, which indicate that the rate and total amount of infiltration are not vary with the slope angle monotonically.