Stability Evaluation Of New Landslide In Lining Highway

With the development of society, road transport is gaining its importance. Highways as banded structure are inevitable to cross slope zone, especially in mountainous districts in Southwestern China, The excavation of cutting readily gives rise to slope instability, so that the landslides happened. The landslide hazard not only affected the quality, investment and maintenance of highway project, but endangered the people’s lives. This paper has researched the Xintuan Landslide in Li-Ning Highway, The geological background and basic characters has been analyzed based on field investigation. The limit equilibrium method and FLAC3D numerical simulation have also been adopted to analyze their stability, so that provide the theoretical basis for landslide treatment.The results showed that the new group is belonging to a giant-soil-covered landslide. The landslide mass is made up of pebbly silty clay clip fragments of stone, earth clamp breccia fragments of stone and some red clay Quaternary colluvium. The slide bed mainly comprises strong weathered off-white dolomite lime. The slip band is the interface of rock-soil body. The formative factors Xintuan landslide includes forming condition and inducing factor. The formative factor mainly is its own geological characters, which include lithology, tectonic, self-weight stress, mechanical parameters of rock-soil and hydrogeological conditions. The inducing factors were divvied into natural factors and artificial factors, mainly present in the excavation of cutting and wash of rain, etc.The limit equilibrium method showed that stability coefficients of the three sections were1.375,1.062and1.057under the natural state, and the landslides are in the state of limit equilibrium in overall. Under the torrential rain condition, the stability coefficients decreased to0.827,0.799and0.779. In the combination of natural conditions and earthquake, the stability coefficients appeared to be0.807,0.792and 0.773; meanwhile, the stability factor is less than1, which indicated the landslide is in an unstable state. Flac3d numerical simulation results revealed that the landslides intend to be stable and most parts of them showed tiny displacement or no displacement. Landslide stability coefficient is1.19, which approach stable state. Under heavy rain, landslide stability coefficient is0.68, which displayed that the landslide was in extremely unstable state. The stability factor K is from0.851to0.883(less than1)by analyzing the existing supporting structures. It is affirmed that the landslides were in Level5unstable state when it was rainy.In summary, the slope may slide once again in current conditions (constant rainy day). Therefore, to ensure the effects of landslides treatment projects and the safety of highway, the anti-slide measures which including retaining and reinforcement must be enhanced and improved.