Abstract：Abstract：It is important to grasp the process of landslide translation to debris flow on the basis of the experiment of landslide translation to debris flow. Four artificial rainfall experiments have been carried out at Wanfangzi，located in the debris flow source area of Jiangjia Ravine，and other four experiments have been performed at the deposit area. The Jiangjia Ravine is a famous debris flow gully. After investigating whole drainage area，the conditions and locations of these experiments are determined. In the process of these experiments，some soil parameters have been measured through some advanced equipments. These parameters are water potential，water content，pore water pressure and soil temperature. After primary analysis have been completed，some basic characteristics of wide-graded gravel soil are presented. Main conclusions include：(1) under the strong-intense rainfall，the mechanism of landslide translation to debris flow is the vibration softening or the vibration liquefaction，and the soil strength can be expressed by the function of grain grade，saturation，and pore water pressure induced by the vibration and infiltration rate；(2) when soil is broken，the soil may be unsaturated，so the mechanism of saturation liquefaction has not been applied；(3) when the curve of water potential declines，the process of soil strength fluctuation will be validated；(4) the energy exchange exists in the process of soil break；and (5) under the strong-intensity rainfall，it is difficult to distinguish the start of landslide against the formation of debris flow，because the characteristics of debris flow appear when soil is broke.
