Study On Stability And Slope Protection Performance Of Gabion Retaining Wall

The long-distance gas pipeline usually passes through mountain area which geologictopographic condition is extremely intricate.In order to avoid the rainfall-induced landslide and other hazards,and ensure the safety and stability of pipeline engineering,the construction of engineering protective structures accordingly is necessary.As a new type of protective structure,the gabion retaining wall is suitable for long-distance pipeline engineering due to its excellent permeability and deformation adaptability.Based on a gas pipeline engineering in Taizhou,Zhejiang Province,this paper studies the performance of slope protection and stability of Gabion retaining wall through model test,numerical simulation and theoretical calculation.The main work and conclusions of this paper are as follows:1.Based on the actual engineering conditions,a scale model of slop with variety of hydraulic protection measures including Gabion retaining wall was established,and the scour resistance test with rainfall duration of 20 min was carried out.The results show that:(1)The rainfall erosion type is mainly rill erosion after setting Gabion retaining wall,the scouring rill has a obvious decrease compared with the unprotected slope.(2)With the increase of the gabion retaining walls,the erosion resistance of the slope is improved.While,it will lead to the over excavation of slope soil and reduction of soil strength meanwhile.(3)When only one gabion retaining wall was set,the lateral deformation of the upper part of the wall is greater than that of the lower part.The three-dimensional geonet can reduce the vertical deformation of the retaining wall.When two gabion retaining walls were set,the vertical deformation of the two retaining walls shows a basically same change trend during rainfall.(4)When one and two retaining walls were set,the distribution of lateral earth pressure along the wall body shows a “(” shape,and the effect of rainfall on vertical earth pressure at the wall toe is more significant than that at the heel.2.In order to further study the effects of rainfall intensity and duration on the stability of gabion retaining wall and slope,a numerical model of slope protected by three gabion retaining walls with rainfall duration of 72 hours was established.The calculation results show that:(1)After 72 hours of rainfall,the maximum lateral stress of the three retaining walls all located at the bottom of the wall,the vertical stress at the middle of the wall bottom is basically the same.And the closer the retaining wall is to the slope top,the greater the overall vertical deformation is.(3)The lateral and vertical deformation of the wall body increase with the increase of rainfall intensity,while the effect of rainfall intensity on lateral and vertical stress is slight.(4)The influence of rainfall intensity on slope stability is greater than that of rainfall duration,and the stability of upper layer is more sensitive to rainfall.3.The stability calculation model of Gabion retaining wall considering rainfall infiltration was established.The influencing factors of retaining wall stability were analyzed based on the model.The calculation results show that:(1)After the trend of slide down presented in the upper layer of slope,the stability of the retaining wall decreases sharply with the increase of seepage depth,and first decreases rapidly and then tends to be stable with the increase of slope inclination.(2)The increase of retaining wall spacing will reduce the stability of retaining wall.(3)The increase of the bottom width of the retaining wall can simultaneously improve the performance of sliding and overturning resistance,while the increase of the wall height will lead to the rapid reduction of the anti-overturning performance.