A novel electroosmosis-heating method for heaving reduction of sulfate saline soil during cooling process

Abstract

The salt heaving of sulfate saline soil seriously affects the safety and service lives of various facilities in saline soil areas worldwide. Electrosmosis-heating (EOH) can theoretically mitigate the serious influence, but its mechanism is unclear. A series of salt heaving and microscopic experiments were conducted using EOH and electron microscopy, respectively. Soil temperature, relative humidity (RH), salt heaving and microstructure in the experiment were monitored and analyzed at different electric potential gradients and electrode sizes. The experimental results show that salt heaving can be effectively reduced by EOH. Soil temperature, RH, salt heaving and its reduction increase with increasing electric potential gradient and electrode size. The above variables increase with time at relatively high electric potential gradients while the first two variables are reduced under lower ones. The mechanism of EOH heaving reduction is the increase of soil temperature and RH caused by heating, the reduction of water and salt content induced by electroosmosis, and pore space is reduced. The effects of electroosmosis and heating on the reduction of salt heaving decrease and increase respectively with the rise of potential gradient. This research provides a theoretical basis for using the EOH method to prevent salt heaving in sulfate saline soils.