Experimental Research On Shear Parameter Of High Cut Slope Gravel Soil In Badong And Its Engineering Application

With the construction of the Three Gorges Project, the impoundment of Three Gorges reservoir, as the one or two terraces in Three Gorges reservoir area which are suitable for human life and living were flooded, the construction land of reservoir resettlement are serious shortage, people had to excavate on the complex geology of poor conditions, even the landslides and other accumulation body of disasters, forming a large number of high cut slopes. They may lead to instability of rock and soil reservoir banks and even cause a large-scale landslide hazard. Therefore it is necessity to carry the stability analysis and treatment on high cut slope. Rock and soil shear strength parameters is the premise of analysis of the high cut slope stability,the rationality of parameter values directly affect the accuracy of the results of the analysis of high cut slope stability. The high cut slope of reservoir-bank road and city buildings are mostly the gravel soil after excavation. Gravel soil is a kind of highly inhomogeneous and noncontiguous material which is different from soil and rock mass, being widely distributed over the Three Gorges Reservoir bank slopes. For the gravel soil have a significant feature is that it generally contains gravel, combined with the large grain size, coarse-grained content and specimen size have much effect on the gravel soil strength behavior. As a result selected three gorges immigrants new town Badong high cut slopes gravel soils as the research object,the indoors large scale direct shear apparatus is used to test direct shear strength behavior of the gravel soil .1. This paper summarizes and analyzes the research status of gravel soils, and pointed out that the current shear strength parameter selection problems need to be solved. On this basis, the paper put forward the main job.2. From natural and geographical conditions, geological structures, landform, distribution of geological disasters and dangerous effects four aspects introduced geological survey of Badong. Badong high cut slopes geological conditions including the area typicality and structure of high cut slopes component typicality. On the basis of geological condition analysis, explained the pertinence and effectiveness of select Badong high cut slope gravel soils as the research object.3. Introducing the main components,main technical indices ,structural principle and the operating process of the large size direct shear apparatus. According to the test scheme, selected three different soil samples of Badong high cut slopes, many groups of large direct shear tests has been taken under different water content and different gradation. Combining with laboratory test results , discussing the influence of high cut slope gravel soil shear strength parameters by large-scale direct shear apparatus inherent defects,geological representation, the size range of normal stress imposing during the test,the number of the test,water content of sample and particle size distribution of sample. We found that these factors are the important random variables of c,φvalues after study.4. Select reservoir slope-JiaoJiaWan high cut slope, combined with high cut slopes engineering laboratory test shear strength parameters and existing engineering geological material, combined the indoor large direct shear tests and parameter inversion analysis two methods to select suitable parameters of engineering practice . JiaoJiaWan high cut slope stability is analyzed. Proof the effectiveness of two methods combined-indoor large shear test with parameter inversion analysis to obtain shear strength parameters.