Experimental study on water-heat-salt migration and deformation characteristics of sulfate saline soil under rainfall

To clarify the water-heat-salt migration and deformation characteristics of sulfate saline soil under rainfall，based on the climate characteristics and saline soil types of the Hexi region in Gansu Province，a geometric similarity ratio model(1∶6) of the natural site of sodium sulfate saline soil was made using the self-developed indoor baseplate-atmospheric dual-temperature control model box. Combined with the surface energy budget balance characteristics for the first time，this natural site model was used to study the multi-physical fields coupled changes within the sodium sulfate saline soil under no rainfall and rainfall. The results show that rainfall can lead to a decrease in reflected shortwave radiation，downward longwave radiation and surface temperature，an increase in surface net radiation and surface evaporation rate，and the increasing trend is related to rainfall. The rainfall leads to an increase in soil water content and conductivity，as well as a decrease in soil heat flux and temperature. Meanwhile，the rainfall leads to an increase in the heat release time of sulfate saline soil. In addition，the influence of rainfall on the water-heat-salt physical fields within the sulfate saline soil gradually weakens with increasing depth. During the transition of four seasons throughout the year，the sulfate saline soil undergoes a deformation process of first thawing settlement and then salt frost heave. Moreover，the thawing settlement and salt frost heave deformation of sulfate saline soil show varying degrees of increase under the influence of rainfall. The research results provide certain guidance for addressing environmental disasters and engineering issues in salted regions under the background of climate change. © 2024 Academia Sinica. All rights reserved.