Abstract: In order to explore the law of change between seepage and deformation of soil mass while inflating air into a slope, a two-dimensional finite element model of a 12 m-thick and 100 m-long slope was established to perform a non-complete coupled simulation of seepage and deformation. The formation process of unsaturated zone in slope and the change of the vertical displacement of slope surface soil was obtained by using the intercepting water with compressed air method to reduce the underground water level of slope. The result shows that the formation process of a complete and stable unsaturated zone can be divided into initial inflating stage, unsaturated zone expanding and water level rising stage, unstable two-phase flow stage, and stable unsaturated zone stage. If the aerated pressure is too large or too small, a stable and complete unsaturated zone cannot be formed. When the aerated pressure is 100 kPa, the vertical displacement of surface soil increases at first and then reduces. There is a certain synergy with the development of soil unsaturated zone. Under different aerated pressures, the vertical displacement of surface soil upstream to the aerated point increases with the increase of the aerated pressure, and the vertical displacement of surface soil downstream to the aerated point is uncertain.

Key words: seepage, deformation, vertical displacement, aerated pressure, intercepting water with compressed air, numerical simulation