Study on the destruction of backfilled loess slopes by short?term extreme rainfall erosion

摘要

This paper investigates the damage of loess slopes under the influence of short-term extreme rainfall. The experiment took the loess soil of Yan’an City, Shaanxi Province, as the research object, and the backfill loess slopes were prepared with different slope gradient (45°, 60°, and 75°). Artificial rainfall model experiments with a rainfall intensity of 120 mm/h and a rainfall duration of 4 h were carried out on three slopes. The experiments monitored the wet front migration pattern, rainfall infiltration characteristics, water content variation, pore water pressure variation and slope damage pattern. The experimental results show that the infiltration characteristics of rainwater are similar for slopes with different gradients. As the depth of the infiltration increases, the velocity of infiltration will decrease. In the early stages of rainfall, the degree of intrusion can reach 70–80, then decreases exponentially to around 20 as the duration of the rainfall increases. The main failure patterns for the 45° and 60° slopes are splash and scouring erosion failure. For the 75° slope, the main failure pattern is spalling. Short-term extreme rainfall and gradient have obvious effects on the slope failure pattern, especially for slopes with small gradients, and the splash effect and erosion will seriously damage the slope.