Abstract: To evaluate the stability of the Ganlong landslide in National Route G326, the engineering geological conditions and factors that triggering the landslide are identified in detail by the comprehensive field investigation, drilling and other methods. The stability of the landslide under the consideration of the heavy rainfall infiltration is evaluated by the geostudio software. The result shows that the landslide topography is relatively steep, the underlying bedrock is tangential, the engineering properties of rock and soil mass are poor, and the long fissure cutting rock mass formed by the longterm rain erosion leads to the cavitation of the slope body, which constitutes the basic conditions for the formation of a large long daylighted bedding landslide. One week before the landslide, the rainfall intensity reached the highest in the entire year, the infiltration line at the rear edge of the slope raised, the pore water pressure of the slope increased sharply, and the infiltration pressure inside the slope, especially in the middle and front of the slope, reached a peak, and the slope stability sharply reduced. The seepage and pore water pressure induced by the heavy rainfall are the main inducing factors of landslide formation.

Key words: Long Daylighted Bedding Landslide, Cause Analysis, Geostudio, Heavy Rainfall, Stability Evaluation