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依据多相渗流和非饱和土理论,提出在潜在滑坡区后缘进行充气形成非饱和区,截排斜坡后缘来水向潜在滑坡区入渗,以降低潜在滑坡区的地下水位,提高边坡稳定性。采用长边坡二维有限元数值模拟方法,研究充气过程中坡体非饱和区气–水两相流运动特征和地下水位变化规律,为充气截排水技术运用于实际工程提供理论指导。通过分析充气点下游边坡地下水位的变化规律,论证充气截排水方法具有可行性;基于充气过程中非饱和区的扩展过程分析,将充气截排水分为3个阶段,即充气点附近非饱和区形成与扩展阶段、充气形成的非饱和区局部越过地下水位线的不稳定两相流阶段和充气形成的非饱和区基本稳定的截排水工作阶段;发现了充气过程中非饱和区孔隙气压力、孔隙气流速度、孔隙水渗流速度和体积含水量会随时间发生波动性变化,且四者的变化具有良好的相关性,当孔隙气压力随时间增大时,孔隙气体流速也随时间增大,孔隙水渗流速度和体积含水量则随时间减小,反之亦然,此规律的形成主要是气-水的流动性差异和相互驱动作用的结果。
According to the theory of multiphase seepage and unsaturated soil, it is proposed to aerate the trailing edge of the potential landslide area to form a non-saturated area. The trailing edge water of the cut slope incurs infiltration into the potential landslide area to reduce the water table in the potential landslide area and increase the slope stability. The long-slope two-dimensional finite element method is used to study the movement characteristics of gas-water two-phase flow and the variation of groundwater level in the non-saturated zone during aeration, which provides theoretical guidance for the application of aerated cut-off and drainage technology in practical engineering. Based on the analysis of the variation law of groundwater level at the downstream slope of aeration point, it is feasible to demonstrate the method of aeration and drainage by aeration. Based on the analysis of the expansion process of unsaturated zone during aeration, the aerator is divided into three stages, namely unsaturated During the formation and expansion of the zone, the unstable two-phase flow in the non-saturated zone formed by aeration crossed the groundwater level line and the stable operation in the unsaturated zone formed by aeration. The pore-air pressure , Pore airflow velocity, pore water seepage velocity and volumetric water content will fluctuate with time, and the four changes have a good correlation. When the pore pressure increases with time, the pore gas velocity also increases with time , Pore water seepage velocity and volumetric water content decrease with time, and vice versa. The formation of this law is mainly the result of the gas-water mobility difference and mutual drive.