Dujiangyan Grindinm Son Tam Reservoir Landslide Instability Mechanism And Prevention Countermeasures

Landslide is located in Dujiang Villiage, Zipingpou Town, Dujiangyan City, Sichuan Province. Moertan Reservoir is in the leading edge of the landslide. No.317 National Highway passes through the middle and front of the landslide. The width of landslide is approximately 245m, the length is about 90m. On the whole, the thickness of the landslide body is uneven. The back of the landslide is thinner, the middle and the front are thicker. The average thickness is about 12m, the size of volume is about 25×104m3, which is belongs to medium sized.The landslide of Moertan Reservoir in Dujiangyan City has been studied in this paper. The instability mechanism of the landslide are analyzed and comprehensive control measures are made for the property of landslide, the understanding and conclusion are as follows:1. This is the typical landside, which is a soil pull-type landslide induced by human engineering activities.2. At present, the landslide is in the transitional stage of unstable failure from creeping deformation to acute deformation, and the trend of gradual development. The landslide is likely to be in a sharp decline in the production of instability under the influence of rainfall and so on. This process will endanger cultivated land 9530m2, road 200m(National Highway No.137) and the reservoir bank slope protection of the leading edge of the reservoir above the landslide, result in huge losses to the local people’s property and important infrastructure, if we do not take the necessary supporting measures.3. According to the geological characteristics of landslide analysis the mechanism of landslide of Moertan Reservoir, we obtained the factors of landslide formation and induction including topography, stratum lithology, human engineering activities, rainfall and earthquake, etc. The internal factors is topography and stratum lithology, the external factors is human engineering activities, rainfall and earthquake, etc.4. Transfer coefficient method is used for landslide stability calculation, the stability of the landslide under different conditions are concluded.5. According to deformation status and development trend of Moertan landslide, we formulated comprehensive control measures with handle ability, economy and timeliness. Such as comprehensive control measures of the leading edge back-filling, crack filling and cutting off water engineering.