Abstract: The research on the mechanical response of anti-slide piles has seldom considered the influence of intermittent heavy rainfall environment, and cannot reflect the multiple rainfall infiltration and solar radiation evaporation links, especially the nonlinear theoretical analysis method of anti-slide pile in the rainfall environment is relatively rare. Based on the improved Green-Ampt model, the mechanical response of anti-slide piles to intermittent heavy rainfall-induced landslides is investigated by introducing the nonlinear Pasternak foundation model. First, in consideration of the drying and wetting cycle and water evaporation theory, an improved Green-Ampt model for intermittent heavy rainfall is proposed to obtain landslide thrusts by taking the wetting front as a potential sliding surface and assuming the homogeneous landslide soils. Second, the pile-soil interaction is investigated based on the nonlinear Pasternak foundation model, and the Newton iterative difference method is used to obtain the mechanical response of anti-slide piles to intermittent heavy rainfall-induced landslides. Finally, the theoretical calculation results are compared with the field monitoring data, which shows a good agreement. In addition, the rainfall sensitivity parameters including the total number of intermittent rainfall events, intermittent duration, average temperature, slope inclination and rainfall intensity are focused to study their influences on the wetting front characteristics and the mechanical response pattern of the anti-slide pile. The results show that the displacement of the anti-slide pile increases by 43.15% when the temperature increases from 10 ℃ to 40 ℃, and by 116.82% when the rainfall intensity increases from 6 mm/h to 20 mm/h. The development of wetting front depth under intermittent rainfall exhibits a “step” upward trend, and there is an “unsaturated zone → saturated zone”. With the increase of the number of intermittent rainfall events, the wetting front of the slope soil keeps advancing downward and induces landslide when it reaches a certain position. The thickness of the sliding area and the landslide thrust increase simultaneously, the deformation and bending moment of the anti-slide pile also become larger and larger. Its development trend shows a gradual decrease to a specific value. The intermittent duration and the total number of intermittent rainfall events presents a negative correlation with the deformation and bending moment of the anti-slide pile, while the average temperature, slope inclination and rainfall intensity demonstrate a positive correlation.

Key words: intermittent heavy rainfall, anti-slide piles, landslides, Green-Ampt model, nonlinear Pasternak foundation model