关键词: 库水降, 红层岸坡, 稳定性, 响应关系, 浸润线, 滞后效应

Abstract: The bank slope always responds well to its stability when the Three Gorges Reservoir water level fluctuates. A research was done to gain the equation of saturation line when the reservoir water level declines from 156m to145m in a steady speed and from 156m to a height in a steady height. Multinomial fitting was introduced to work out the equation for the initial saturation line. As a typical example, the bank slope of red beds to the northeast of Qianjiangping slope was analyzed and the stability coefficient of the bank slope was calculated when the reservoir water level declines. The results show that when the reservoir water level declines in a steady speed, the higher the speed is, the bigger the deducing rate of the stability coefficient is; the higher the declining speed is, the more remarkable the hysteresis of the groundwater is, but the hysteresis will reach to a peak as the water level declines; when the reservoir water level declines in a steady height, the relation curve between the height and the stability coefficient presents three segments with different declining ratios. As to the slope northeast to Qianjiangping landslide, the critical declining velocity is 1.2 meter per day while the reservoir water declines in a steady speed. When the reservoir water declines in steady height, the critical condition is that the single declining height must not beyond 6 meters. It is significant to guide the prewarning and forecasting of geologital disaster which is similar to the bank slope in the Three Gorges Reservoir.

Key words: decline of reservoir water level, red beds bank slope, stability, response, saturation line, hysteresis