Study On The Prediction Criterion Of Bedding Landslide In The Area From Zigui To Badong Segment Of The Three Gorges Reservoir Area

Bedding landslides are widely distributed in the area from Zigui to Badong which is the head part of the Three Gorges reservoir. The reservoir water level, rainfall, human engineering and other factors made a combined effect to the stability of band slopes, especially in the head part of the Three Gorges reservoir. This paper selected bedding landslides in the area from Zigui to Badong as the research object based on the monitoring data of the two stage geological disaster warning work from the Ministry of Land and Resources, then made some research on the response rule between the landslide deformation characteristics and factors such as reservoir water and rainfall.This paper selected Kaziwan landslide, Baishuihe landslide and Muyubao landslide as the study object, while made an analysis of its deformation depend on each landslide displacement monitoring data. At the same time, the Two-step clustering method is used for the classification of monitoring data, reservoir water and rainfall. Then get the association rules of landslide displacement monitoring data and factors such as reservoir water factor (monthly average water level, monthly water level fluctuation and monthly water level single-day lift the maximum amount), rainfall factor (month cumulative rainfall, monthly largest single-day rainfall and the largest single-day rainfall greater than10mm days) based on the Apriori algorithm. At last, an analysis was made to explain the association rules through the work of the study of response pattern between landslide displacement monitoring data and reservoir water, rainfall. Based on the analysis of these issues, conclusions came as following:1.Through the analysis of the landslide displacement monitoring data, the front and middle part of the Kaziwan landslide variants much worse than the rear part, and the whole landslide shows a typical tractor-like landslide displacement characteristics; the deformation of Baishuihe landslide mainly happens in the front part while the rear part is less, and the whole landslide shows a traction displacement characteristics; the Muyubao landslide shows an overall displacement characteristics except bigger one like ZG291and smaller one like ZG300and ZG301.2.The response of Kaziwan landslide, Baishuihe landslide and Muyubao landslide to rainfall is obvious, while Baishuihe landslide is stronger than the other two. The response of Baishuihe landslide and Muyubao landslide to intensity rainfall is stronger than Kaziwan landslide. The response of Baishuihe landslide to continuing rainfall in and above is obvious, while Kaziwan landslide is less, Muyubao landslide is worst.3.It’s not good for the stability of the landslide when rain infiltrate into the landslide. At the same time, the material of Kaziwan landslide and Muyubao landslide contains hydrophilic material composition; when continuous rainfall happens, it’s easier to form a thick liquid film on the surface or between the gaps, then permeability becomes lower. For that reality the response of Baishuihe landslide to Continuing rainfall in and above is higher than Kaziwan landslide and Muyubao landslide. The reservoir water is a sicker factor to the stability of the three landslides, and the response differs in the three landslides.In summary, the prediction criterion of bedding landslides came as the following:1. permeabilityThe permeability of bedding landslides manifests two aspect as gap between rock and the permeability of rock itself. The rainwater easily gets into landslide body through the gap between rocks. At the same time, it’s difficult for the underground to be discharged because the bad permeability of rock.2. rainfallThe influence of rainfall to bedding landslides acts on two ways as intensity and time, and shows on month cumulative rainfall, monthly largest single-day rainfall and the largest single-day rainfall greater than10mm days. These three impact the stability of landslides on increasing the amount of rainwater infiltration.3.topographyWhen the rock of bedding landslides show the topography that the superior part is steep and underneath part is smooth, the front part is a resistance to the slip. The buoyancy puts an effect on the front part of landslides which wading reservoir to reduce the slip resistance. In this way, it’s no good for the stability of bedding landslides.