Application Of Siphon Drainage Method In The Treatment Of Hengshan Road Landslide

The deformation and failure mechanism of landslide is the core content of landslide research.And it is also the basis for landslide treatment,prediction and risk assessment.The differences between individual landslides are large,and it is especially difficult and important to analyze the deformation and failure mechanism of landslides under complex geological conditions.Compared with the traditional slope drainage measures,the high-lift siphon drainage has the advantages of no power,long-term and fast construction.These advantages are especially prominent in the rainfall-induced landslide treatment under complex geological conditions.Hengshan road landslide is located in the mountainous area of western Zhejiang province.Due to local excavation during the construction of the road,several excavation slopes have been formed,and signs of deformation have slowly appeared.After the corresponding treatment measures are applied to the various deformation slopes,the deformation of slopes has not been eliminated.Therefore,it is necessary to conduct an in-depth study on the deformation mechanism and propose effective prevention measures.This paper uses the deformation monitoring data as well as geological data to correct the conclusion that the slope deformation is shallow and partial sliding in the early stage,and proves that Hengshan road landslide is an "Deep-seated and overall" landslide caused by the resurrection of ancient landslides.According to the landslide induction mechanism,high lift siphon drainage technology is proposed for landslide control.In order to ensure the reasonable and effective application of the method,it is necessary to solve the problem of sedimentation in the siphon.Therefore,a mathematical model for the initiation of particle sedimentation with a particle size of 0.5 to 1 mm in a slanted siphon is further established.The starting velocity of the larger particle sediment in the siphon oblique hole was calculated and analyzed by using the moment balance equation and the probability distribution of the geometric parameters.Two calculation formulas of the sediment starting velocity in a 4 mm siphon drain pipe related to the pipe inclination angle,the pipe inner diameter and the sediment particle size were obtained.These two formulas were further verified in comparison with the empirical formula and the physical model test results.According to the deformation mechanism of the "deep-integral" landslide and the high groundwater level and complex terrain,the siphon drainage treatment method of the slope is designed by using the derived sediment initiation equation,which can effectively discharge groundwater and Significantly reduce siltation in the pipeline and ensure the long-term sustainability of siphon drainage under complex geological conditions.