The Loess Along The River Subgrade Slope Treatment Methods Research In Haidong Ping'an County Convention Road

With the deepening of the process of west development the Haidong city of Qinghai province Ping'an county proposed the Exhibition road, communicated with Haidong and Xining City from east to west, and improved economy in related areas. Since the site of this road widespread collapsible loess and the loess sinkhole prone to collapse deformation under the water situation; and affected by terrain and environment the proposed road will wiring along the river, road slope is easily deformed by water erosion and infiltration in the process of changes in the river along the coast.The focus of this paper is to analyze the impact of changes in river level on the river embankment slope stability and study the reinforcement of the slope of the Exhibition Road in order to provide a theoretical basis for the design and guide the construction smoothly.In this paper, takes the object of study by along the loess embankment slope, the main work and conclusions are as follows:1.Based on the detailed analysis of the environmental and engineering geological conditions in the Exhibition Road preliminary explore the slope destabilization causes and qualitatively identify the main factors affecting slope stability.2. Based on the theory of unsaturated seepage and the fundamental of the limit equilibrium method and finite element strength reduction and the flow-solid coupling principle, combined discrimination method of the three kinds of water down mode, analyzed the slope stability by the software of Midas GTS.3.Considering the factor of the changing speed level, the water level drop ratio, the permeability of the filling material, matrix suction, natural vertical cracks of the loess slope impact on the Exhibition Road safety factor. Contrast the results of limit equilibrium method and finite element strength reduction, study of the impact of each factor on the seepage field of the Exhibition Road slope in-depth and the variation of the displacement field, strain field and the safety factor under the action of the flow-solid coupling.4.Studied of the characteristics of the foam light soil in depth, combined the resulting response of the different factors under the Exhibition Road slope stability, proposed design of the Exhibition Road Slope Reinforcement Project and conducted research on the construction technology.The study concluded that:the most important factor to Exhibition Road slope stability is water level change in coastal rivers and the adverse geological conditions of the loess in proposed site. The main mechanical mechanism which the cause of the slope failure is the pore water pressure difference between inside and outside slope. Safety factor of slope reduces with the increases of the drawdown rate and ratio; the rate of change of the safety factor increases with the reduces of the permeability coefficient of the slope embankment material; consider matric suction can increase the soil shear strength of the slope; consider loess vertical fracture to the surface, the water rapid infiltration along the cracks will accelerate the formation of the unstable flow field. Application the method of the foam light soil replacement to reinforce the loess slope along the river can effectively reduce the phenomenon of slope instability due to seepage of water on loess erosion.