The Deformation Rule Study Of Bedding Landslide In The Area From Zigui To Badong Segment Of The Three Gorges Reservoir Area

The Three Gorges reservoir area is one of typical prone to geological disasters in our country. The area from Zigui to Badong segment of the Three Gorges reservoir area with most special geologic environment is one of sector mostly affected by impoundment, bedding landslide with variable obliquity developed widely, especially large and medium type of rock slope. Once it failure, the landslide is massive, abrupt and dangerous. So studying the deformation rule of bedding landslide has important theoretical value and social significance.Based on the data collection, field geological investigation, etc, the area from Zigui to Badong segment of the Three Gorges reservoir area was taken as the research object. Firstly, the deformation rule of bedding landslide in the area from Zigui to Badong segment of the Three Gorges reservoir area was studied, and the development characteristic of large bedding landslide was also summarized. Then this paper analyzed the factors that affect bedding landslide stability, and the failure mode and buckling mechanism of bedding landslide were studied. Finally, focused on deeply study, taking Muyubao landslide in Zigui county as an example, from the quantitative point of view using data mining technology to explore the bedding landslide deformation trend and the variation characteristics of stability under outer power (such as rainfall, water level rising or falling).The research results are summarized as following:1. The number of bedding bank rock slope from Zigui to Badong segment of the Three Gorges reservoir area is39, which accounts for70.9%of total rock landslides, accounting for45.35%of the total landslides. The results show that bedding rock landslide widely distributed. The bedding rock landslides developed in300to400m slope height and in15°to30°slope range; developed in multiple tectonic system handover of composite parts, drape and fracture development areas, in parts of the syncline and anticline fold turning parts of the transition, and the ground soft and hard white or soft interlayer with thin strata among the main scale to large and medium. Bedding rock landslides are developed in the Triassic and Jurassic strata in the system or the hard and soft white soft interlayer with thin strata among the weak interlayer constitutes a controlling deep sliding surface. Bedding rock landslide controlling factors is smooth and easy formation of its geological structure, the rainfall and reservoir water is the most important incentive factors.2. Many landslides that have happened in study area show that different types of bedding rock landslides have different development rule, then influencing the stability and deformation evolution mechanism are also different. There are both characteristic and commonness. In this paper, firstly choosing typical landslides, divided into four categories:flat-shaped monoclinic old landslide, wavy bedding or ladder-like landslide, on the steep bedding of slowly armchair landslide, on the steep bedding of slowly down steep landslide. Secondly, based on the bedding rock deformation and failure mechanism of landslides studies, summarized the bedding rock landslide failure modes:single oblique straight like old landslide deformation failure mode is Slip-cut mode, completely planar failure mode and mode-collapse song-bedding sliding; variable angle like old landslide deformation mode is sliding-bending-bedding sliding. Finally, three failure mechanisms of the bedding rock bank landslide were summed up:unstable slip zone softening soak by reservoir, cutting and lateral erosion of river, deformation instability of earthquake disasters.3. Taking the Muyubao landslide as a typical bedding rock landslide, time series decomposable model was used to decompose the displacement into trend term and period term by moving average method. The trend term displacement of ZG291, ZG292, ZG294was predicted by displacement polynomial function, and the prediction correlation coefficient respectively is0.990,0.990,0.989. Based on selecting five influence factors which induced the deformation of bedding rock landslide, the multivariable BP neural network was adopted to predict the periodic term displacement, and the prediction curves were consistent with the measured results. Finally, the prediction values of trend displacement and periodic displacement were superposed to obtain total displacement prediction. The relative error of predicted results is small, that less than4.52%,4.92%,4.88%, and overall fitting and prediction results are reasonably consistent with the development trend of the measured displacement. The results show that proposed method effectively reflects the relationship between displacement landslides with the external influential factors. It is an effective method for prediction of bedding rock bank landslides.