Research On The Effect And Influencing Factors Of Slope High-lift Siphon Drainage

With the rapid development of social economy, the governance and research task of slope engineering is becoming more and more important. In the process of various engineering project construction, it often forms slope, whose stability and governance are the key factors to affect the progress, quality and schedule of the projects. Landslide is a phenomenon that slope’s rock mass slides along the run-through shear slip crack surface, and is one of the main forms of geological disasters. Groundwater reduces the shear strength of slope body, increases the sliding force, is one of the main factors that induce landslide disaster. Slope engineerings are usually divided into two forms, one is the prevention and cure project that controls landslide, another is the project that directly governing landslide movement.The siphon drainage effect improves the stability of slope mainly by changing the shape and distribution of underground water level. Siphon drainage can realize unpowered and real-time drainage, which is a new technology collecting economy and timeliness in the integration. The siphon drainage is still in the stage of exploring application in side slope engineerings, therefore its persistence, effectiveness and influencing factors is yet to be studied.This paper explored the effect and influencing factors of the high-lift slope siphon drainage mainly through the finite element numerical calculation, taking generalized Darcy’s law and the basic principle of seepage field analysis as the theoretical basis.(1) Based on generalized Darcy’s law and the basic principle of seepage, combining the "pipe to represent hole" method and analytical element method, a numerical simulation method for siphon drainage system was proposed. In order to simulate the process of siphon drainage, we gave the drainage hole a equivalent permeability coefficient according to the equivalence principle of flow and head. Meanwhile the hydraulic boundary conditions according to the principle of the siphon drainage were determined. Finally, we confirmed the rationality of this method with the test data. (2) We established the assumptions, and set up a three dimensional seepage model of slope. Taking the model with a single drainage hole as an example, we calculated the underground water line and the change of seepage field distribution in the slope before and after siphon drainage, and analyzed the siphon drainage effect.(3) Based on the above three dimensional seepage model of slope, through varying the layout height of the siphon drainage system, we calculated and analyzed the corresponding drainage effect, and summed up the influence law of drainage hole’s layout height to slope seepage field and underground water level distribution, which provided the theory basis for choosing the best drainage layout position in practical slope engineering.(4) We discussed the influence law of drainage holes layout spacing to slope siphon drainage effect in the case of multiple drainage holes, through comparative analysis, we concluded the corresponding hole spacing when the drainage efficiency is highest, which provided the theory basis for choosing the best hole spacing in practical slope engineering.(5) The tilt Angle of drain hole is also an important factor to influence the siphon drainage effect. By calculating the corresponding slope seepage field distribution in conditions of different tilt Angle of drain hole, we summarized the relationship between the tilt Angle of drain hole and seepage discharge, ground water distribution, as well as the slope stability.