Sliding Stability And Debris Flow Risk Assessment Of 07 Section No.5 Dump In He-da Expressway

With the rapid development of economy,our country has been strengthening highway construction while in the process of highway construction,a large number of abandoned soil and slag will be produced,especially in mountainous areas.Waste dump is a common project in highway construction,the lack of scientific and reasonable site selection always lead to the phenomenon of carelessly dumping.Without any risk assessment and control measures,the soil is easy to be affected by precipitation and dynamic load and will lose stability even develop debris flow when conditions are ready.He-da Highway 07 section No.5 waste dump is located in a south gully close to Songjianghe village,next to the national highway G201.The total dump is 2.1×105 m3,covering an area of 5.867 hectares.There are a large number of loose stones in the abandoned soil.Both sides of hillside are steep and the catchment condition of gully is good.In this paper,the sliding stability of the waste dump is analyzed and the risk of debris flow disaster is evaluated.Conclusions are as follows:1.Among three possible sliding modes of dump,the minimum stability coefficient of sliding along the original slope is 2.207(Janbu Method)and 1.908(Imbalance Thrust Force Method);minimum stability coefficient of internal partial sliding is 1.518 internal(Janbu Method)and 1.262(Imbalance Thrust Force Method);dumping will not cause bedrock internal sliding.Therefore,the stability of the soil mass is good and no sliding will occur.2.When using the first grade fuzzy evaluation,the debris flow danger degree before dumping is 0.507,which is no danger,indicating that debris flow cannot happen,and the debris flow danger degree after dumping is about 0.764,which is trifling danger.When using the secondary fuzzy comprehensive evaluation,the debris flow danger degree after dumping is 0.729,which is trifling danger.3.Geotechnical engineering can be used combining with biological engineering measures to control the dump debris flow,meanwhile,we should strengthen people's propaganda and education,if necessary,residents in the danger region should be relocated,so as to ensure the production and daily life of local residents and property security.