Experimental Study on the Influence of Temperature on Salt Expansion of Sodium Sulfate Saline Soil

Abstract

To find the rule on the effect of different temperatures on salt expansion of sodium sulfate saline soil and ensure the safety of road engineering in areas with sulfate saline soil, we tested saline soil samples in a laboratory. By analyzing the variation in soil samples before and after cooling and the variation in water content under different temperatures, we determined the influence of salt expansion on soil components under different temperatures by using computed tomography. Results show that salt expansion intensifies and tends to stabilize under decreasing temperature. Salt expands mainly from 0°C to the initial precipitation temperature of salt crystals, and very slight precipitation occurs at a negative temperature; thus, salt expansion is very low at temperatures below 0°C. Moisture content decreases as temperature decreases, and the diminishing trend decreases and gradually stabilizes at 0°C. Damage in soil structure increases as temperature decreases. Change in porosity occupied by air is mainly determined by change in water content. Porosity changes acutely with acute changes in water content, and these parameters show an inverse relationship.