Abstract
Rainfall is one of the most important factors inducing landslide occurrence, and previous researchers have carefully studied the stages of rainfall infiltration as well as the factors that affect infiltration (e.g., rainfall intensity, rainfall duration, initial water content and dry density). However, previous studies using homogeneous soils were overly idealised and ignored the effects of water content and dry density on infiltration, which vary with depth. In this paper, based on indoor rainfall infiltration tests under the above initial conditions and influencing factors, the following patterns were found: (1) dry density and water content of natural soils tend to increase along the direction of gravity under long-term gravity and repeated rainfall evapotranspiration; (2) stepped dry density increases infiltration resistance, which increases the total response time; stepped initial water content decreases infiltration water volume, which decreases the total response time; stepped dry density and water content have the shortest total response time;(3) The increase in dry density delayed the sudden change point in the permeability coefficient, and the initial moisture content had little effect on the sudden change point.