Experimental Study On Salt-frost Heave And Microstructure Of Crude Saline Soil In Xin Jiang

In order to research the salt-frost heave laws under different cooling mode and internal microstructure in Xinjiang area of natural saline soil, the natural saline soil of Lop Nur and Ai Dinghu area were selected for the experiment of freezing- thawing cycles in open system, the effects of the microstructure of natural Saline Soil after freezing- thawing cycles by using SEM. The results showed that: The temperature of the area's low liquid-limit silt is 5?-0?, soil have obvious expansion, the temperature is start salt expansion. During the cooling process, the expansion of the soil can be divided into 3 stages. First stage of the start salt expansion,the second stage of salt expansion growth stage, the third stage of salt- frost heave common growth stage. The temperature variation of the area's sulfurous saline soil is a parabolic function, first layers of soil temperature change range-5.0 degrees Celsius to 17.5 degrees Celsius, 2, 3, 4, 5 layer of soil temperature change range in the range of 0 degrees, Soil has good salt accumulation.In the process of freezing-thawing cycles Ai Dinghu area both saline soil has good salt frost heave a cumulative. Because the two big difference on saline soil containing salt, and a variety of salt content is not the same, of two kinds of saline soil is a bigger difference, the salt frost heaving of soil when the salinity is long to the salt frost heaving tends to stable for a long period of time. The Ai Dinghu area in salty soil area of single factor study shows that soil salt frost heave in a certain range will be with the water content, dry density increases gradually increased, but when the water cut is more than the optimum water salt frost heave but will reduce the, when the soil is too dense will offset some of the salt heaving.By electron microscope scanning of saline soil after freezing-thawing cycle microstructure observation, the sulfate content in saline soil is more different shape change and volume of the salt crystals larger, the formation of salt crystals easily wrap soil particles, particles of soil between is filled with salt crystals, is given priority to with chlorine salt soil, the soil salt crystals shape relative sulfate are more rules, most of the attached on the surface of soil particle.