The Research Of Long-Term Shear Strength Of Clinosol And Time-Varying Of Slop Stability

Slope stability is a traditional study issue of geotechnical engineering and serves as an essential part in the landslide early warning, so as an important reference for project design and establishing corresponding protective measures. Along with government’s continued investment on construction of transportation facilities in China Midwest, many highways are constructed in the mountainous area with complicated topographic and geological conditions. It raises a number of high and abrupt clinosol slopes. These slopes require intensive monitoring when the probability of landslide is concluded to be large in slope modeling analysis. Once any traces of slope creep are observed in the excavation, timely treatment for the crept slopes is on demand. On the process of establishing the treatment scheme, the shearing strength indexes c and ? are prerequisite, and how to identify effectively and accurately their values is a problem needing investigation. Based on the above, this work devoted on the following topics and achieved some conclusions.(1) Based on the principal of direct shearing test, the long-term shear strength tests in laboratory were conducted. The variation of shearing strength was obtained when the remoulded clinosol soil is creeping on various water contents.(2) Based on the time-varying of shear strength,this paper considering based on the time- varying of limit equilibrium, introducing the variation into the slope stability analysis resulted in the varying pattern of FOS of slopes against time development.(3) Strength reduction method was used to asses the slope stability by programming FLAC3D finite difference strength reduction procedure, the results were compared with the FOS obtained by Bishop’s Simplified Method.(4) On consideration of the fuzziness and uncertainty in selecting the protective schemes, fuzzy comprehensive evaluation approach was employed to the optimal selection of protective schemes for highway slopes. It overcomes the subjective arbitrary in choosing the influence factors of scheme selection, and is able to achieve more scientific and reasonable protective scheme.