| Expressways are an important part of the national transportation network,and they play an important role in people’s travel and the transportation of goods.Highways pass through mountains and rivers.Natural impacts and damage to highways occur from time to time.Among them,landslide disasters are the most common and have great destructive power.When landslides,a large number of rock and soil blocks traffic from time to time during the specific construction of some highways,landslides not only hinder the construction of highways and traffic,but also threaten the lives of construction workers and local people.To the corresponding economic losses,so we should increase our attention and attention to the highway landslide management in mountainous areas.Based on the landslide at the A-B ramp between the left side of AK0 + 590 ～ AK0 +612.985 and BK0+330～ BK0 + 389.302 from Hechi to Baise highway,this study conducted the following work:(1)Collect the natural geographical conditions and engineering geological conditions of giant ancient landslides.Conduct field surveys to find out the basic characteristics and development of the landslide;according to the physical and mechanical parameters of the landslide rock and soil obtained from the on-site in-situ tests and laboratory tests.Through drilling to understand the basic morphological characteristics of ancient landslides,the whole landslide is a composite landslide which is triggered by traction and then converted into a push-type landslide.(2)Analysis of the formation mechanism of the landslide.Heavy rain caused the slope body water to seep into the slope body,making the upper soil layer softened into a weak slip zone when encountered with water,and the free surface was formed due to the excavation of the roadbed,resulting in stress redistribution of rock and soil.Eventually led to the formation of landslides.Two working conditions were calculated for three different sections of the landslide,and a secondary sliding surface was also calculated separately.The calculation results show that the natural state stability coefficients of the four calculated sections are between 1.01 and 1.33;in the saturated state,the stability coefficients are 0.95 and 1.25,and only one section is in the stable state,which is basically consistent with the results of the qualitative analysis.(3)In the selection of treatment plans for ancient landslides and shallow landslides,after comprehensively considering various factors such as retaining effect,construction difficulty,construction period,land acquisition scope,project cost,etc.,the anti-slide pile treatment plan according to ancient landslides was finally selected.(4)The landslide control measures effectively eliminated the hidden safety hazards of landslides,controlled the downward trend of large-scale earthwork,strong anti-slide piles have played a good role,reinforced soil enhanced the anti-sliding force.The treatment project provides a safe and smooth traffic order for highway operations.The stability of the landslide after the ancient landslide treatment plan is calculated is calculated.The stable safety factor is between 1.21 and 1.39.The situation is between 1.13 and 1.33,and the stability evaluation is stable,which verifies the effectiveness and scientificity of the governance plan.(5)With the rapid development of expressways in mountainous areas,the problem of controlling large-scale ancient landslides has become increasingly prominent.This study is helpful to provide references for large-scale or narrow-segment ancient landslides,including topographic features,hydrogeological conditions,and landslide occurrence mechanism.And,most importantly,this article provides a governance plan as a reference to achieve the goals of reasonable protection,reducing excavation,solving hidden dangers once and quickly restoring traffic order. |
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