The Stability Analysis Research Of Shiyan-tianshui Expressway Expansive Soil Slope

Expansive soil is an special clay that has water significantly expanded and water losssignificantly shrinkage characteristics. Expressway construction in the Expansive soil regionare often slump disasters, Its seriously restricting the construction of high-grade highways inChina’s central and western expansive soil region, so carry out expansion soil slope stabilitystudy has important practical significance.This paper take Shiyan-Tianshui Expressway expansion soil slope engineering practice asthe basis,throngh the expansive soil tests and investigations along the Shiyan-TianshuiExpressway,Get the expansive soil causes and distribution, Analysis of the composition andengineering properties of expansive soil;by Investigation the expansive soil cutting slope,Summed up the type of expansive soil slope instability; Analysis of the mechanicalmechanism of expansive soil slope failure cutting by use the unsaturated soil Fredlundstrength formulas and saturated soil principle of effective stress.Summary domestic and international slope stability analysis method.In this paper useFinite element analysis method study the Shiyan-Tianshui Expressway typical expansive soilslope-K116+420to+650segments expansive soil slope stability. Get this slope Physical andmechanical parameters from the geological survey data, create this slpoe MIDAS-GTSthree-dimensional numerical model. From the four conditions: natural slope, slope excavation,excavation completed rain, anti-slide pile governance completed to simulate analysis the slopestability. Get different stages of expansive soil slope stability factor ti evaluate the slopetsability; Contrast numerical simulation analysis of displacement to the actual monitoringdisplacement.Analysis rainfall conditions, Consider the affected of expansive soil fissure depth.Thispaper use seepage analysis of simulate rainfall infiltration various stages the pore waterpressure of expansive soil slope soil, analysis different rainfall intensity and rainfall durationslope soil pore water pressure. On this basis, use seepage-stress coupling analysis the slopestability. Heavy rains and earthquakes role the most important factor affecting on expansivesoil slope stability in expressway operations, adopt MIDAS-GTS finite element softwarepredicting the K116+420to+650expansive soil slope stability in both cases.