关键词: 泥石流, 黏粒含量, 启动产流, 临界性, 持水能力

Abstract:

Content of clay particles in debris flow is not much, but it significantly affects the occurrence of debris flow. Indoor artificial rainfall experiments are carried out in self-designed model with nine different graded soils, three different dry densities (1.64 g/cm3 (loosely accumulation dry density), 1.79 g/cm3, 1.94 g/cm3 (natural dry density)), rainfall intensity 85 mm/h, impact which content of clay particles on debris flow occurrence is preliminarily studied. As a result, it’s found that debris flow can occur when content of clay particles is between 5% and 18%, it needs shorter time when content of clay particles is 10% than others; clay content has criticality. The greater the dry density of accumulation, the more difficult debris flows to occur with long start-up time, shallow depth and small scale, but accumulation dry density does not change the criticality of clay content. Under the condition of rainfall, the higher the soil infiltration rate of soil, the stronger the water-holding capacity of soil, the easier debris flow to occur. The internal mechanism of forming debris flows can be revealed deeply through above experiments; it also develops new ideas on debris flow forecasting.

Key words: debris flow, content of clay particles, start of runoff, criticality, moisture holding capacity