Effects Of The Attitude Of Bedrock On The Loess-bedrock Landslide In Heifangtai Area

Loess-bedrock landslides which have a great of hazards and bring a lot of losses to the local economics distribute in the area of Heifangtai, Yongjing County, Gansu Province. The structure of rock mass often makes notable influence on the loess-bedrock landslides. The attitude of bedrock is the most important factor in slope stability analysis.This article takes the loess-bedrock landslides as the research object. First of all, analyze the characteristics of distribution and occurrence of landslides based on summarizing the research status and collecting information. Secondly, study the relationship between the attitude of bedrock and the landslides. Finally, simulate the landslides using FLAC3D software. The main conclusions are as follows:(1) The landslides distribute in the south of Hei platform and the southeast of Fang platform. The landslides have liability to occur when the slope length is300-400m, the slope width is400-500m, the slope height is110-130m or the distance is0-100m.(2) The apparent dig angle of bedrock affects the landslides. When the angle increases, the landslides contribution rate first increases and then decreases. The largest contribution rate is15-20°, the smallest contribution rate is20-25°. The angle between trend of bedrock and glide direction influences the landslides. When the angle increases, the landslides contribution rate takes on the trend of increase-decrease-increase. The largest contribution rate is10-20°, the smallest contribution rate is0-10°and20-30°.(3) The simulation analysis results accord with the actual situation. The landslides easily occur when the apparent dip angle of bedrock is15-20°. It appears two kinds of landslides under the influence of the apparent dip angle of bedrock:the loess landslide and the loess-bedrock landslide.