关键词: 道路工程, V型冲沟, 超高路堤稳定性, 安全系数, 渗流场, 饱和浸润线

Abstract: Natural fluctuation of water level has a great effect on the stability of super high fill in the Three Gorges Reservoir. With continuous rising of water levels, the water will actively infiltrate into the slope under the effect of pore water pressure and seepage flow in unsaturated soils. Firstly, based on seepage calculation theory, FLAC was applied to simulate the seepage field change of the Vshaped gully super high fill in the Three Gorges reservoir when the water level had been rising from 145m up to 155, 165, 175 m. Then, variation rules of important parameters including saturation, pore water pressure, horizontal displacement and maximum shear strain increment were analyzed. The relation between safety factors and different heights (150, 155, 160, 165, 170, 175 m) of rising of water level were researched in three working conditions, including rising of water level, rising of water level under 3D effect condition, rising of water level under 3D effect and two times as much as normal loads conditions. Eventually, calculation results show that: with water level continuously rising, the saturation of the fill increases, which will result in more concave saturated seepage line and higher pore water pressure; the safety factors of three kinds of working conditions are increased, up to the max level (175m), the stability safety factors reach the maximum. The change rate of safety factors decreases first and then increases. The water level rises up by each 5 m; the average safety factors increase about 5% in three working conditions.

Key words: road engineering, V-shaped gully, stability of super high fill, safety factor, seepage field, saturated seepage line