Experimental Study On Engineering Properties Of Slip Soils Of Landslides Along G212 Highway In Longnan

As an important component of landslide, slip soils have close relation with its development, deformation and stability, therefore, study on the shear strength properties of slip soils usually become a necessary part of the landslides research.For the region of Longnan lies in the complicated environment effected by geological, geographical and climate process at upriver of the Yangtze River, it has fallen into one of the areas with most severe geological disaster in China, especially at both sides of Bailong River and its anabranches along the G212 highway, where the landslides develop so greatly that the security of the highway has been threaten seriously. The Geotechnical engineering graduate school in Lanzhou University has taken part in the west traffic construction scientific and technical project "study on the construction technology of the G212 highway (Lanzhou-Chongqing) in Longnan", investigated the landslides to offer scientific references for the road design and prevention and cure engineering of the landslides.Relying on this project, based on the investigation and study at the regional geological environment and the development features of landslides, the engineering properties of slip soils have been tested, including physical properties, compressibility and shear strength. The shear strengths of slip soils is the stress of the test study, which involves peak shear strength (fully softened shear strength) and residual shear strength.By synthetically analyzing the test results, with regard to the stress-strain (τ-σ)curves and shear strength failure envelop under varied level of moisture contents of the slip soils in the work region, this paper analyzed and studied on the feathers and rules of the shear strength characteristics, and preliminarily studied the shear deformation mechanisms and influence factors, and gained that the strength properties of the slip soil have close relation with its configuration and state besides its substance component, and then discussed the correlations between the shear strength parameters(C,φ) and the physical parameters (liquiditx index I_L and maximum dry density ρ_d), and found that there is exponential decay correlation between cohesion (C or C_r) and liquiditx index I_L, and put forth the expressions.References and consults offered in this research will be useful in the choice of the strength index for stability evaluation and control design of the typical landslides along the G212 highway in Longnan.