Study On The Stability And Treatment Effect Of Slope On Jia Jia Shan1#Tunnel Entrance

The geological disasters of tunnel entrance affect the tunnel’s construction and operation.A prominent problem is the slope stability in the tunnel entrance, In this paper, takenlandslide engineering induced by the failure of slope in the Jia Jia Shan1#Tunnelentrance as the study object. The stability and failure of slope and tunnel excavation modelare studied by the engineering analogy and numerical calculation method.The failure of slope in the Jia Jia Shan1#Tunnel entrance mainly experiences threestages, Sporadic failure, Local destruction and The overall damage. Combined With thecomprehensive analysis on the correlation of settlement curves of the rainfall coefficient andconstruction process, the continuous rainfall during the period of construction is the dominantfactor lead to slope failure. Analysis the settlement data of similar engineering, Settlement lagtime caused by rainfall is about24h~48h, among the settlement caused by Constructionprocess,That caused by excavation of core soil is relatively maximal.The stress distribution and Deformation characteristics of Tunnel portal underconstruction are Analyzed by Established dimensional model of Jia Jia Shan1#Tunnel.Tunnel excavation causes the slope toe stress concentration and Shear failure. The slopefailure makes the anti slide force is less than the sliding force of landslide, The trailing edgesof slope occurr tensile failure, this Induces landslides instability. The continuous rainfallmakes the water content of soil increase, and the soil mechanics parameters weaken, whichis the fundamental reason for the failure of slope.According to the treatment plan of Jia Jia Shan1#Tunnel Landslide, the safety factor oftypical landslide calculated by the simplified Bishop, Janbu and strength reduction FEMmethod is1.47,1.466and1.50. the treatment plan effectively improves the safety factor ofslope. The landslide potential slip surface and the shear opening are search out with the finiteelement method, they are Mainly located in the second and three level platform of thetreatment plan, where The construction needs to strengthen the support and make gooddrainage measures.