冻融循环作用下粉砂质硫酸盐渍土变形特性研究OACSTPCD

[Objective]In order to explore the deformation characteristics of silty sulfate soil in southern Xinjiang,[Methods]The freeze-thaw cycle test of silty soil was carried out under closed system conditions,and the soil structure was characterized and analyzed by scanning electron microscopy.[Results]The result showed that the deformation was mainly melt and precipitation when the sodium sulfate content of silty sulfate soil was 0 and 1.0％,and the deformation was-1.30 mm and-1.02 mm after five cycles,respectively.When the sodium sulfate content was 2.0％,5.0％and 8.0％,the deformation was salt expansion-frost heave deformation,and the deformation after five cycles was 2.46 mm,8.53 mm and 3.43 mm,respectively.[Conclu-sion]The result show that the temperature and sodium sulfate content of silty sulfate soil under freeze-thaw cycle are the main fac-tors affecting the freeze-thaw deformation of soil.The deformation of soil in the low temperature interval is manifested as salt expansion-frost heave with the decrease of temperature,and ice melting and salt dissolution deformation occur successively in the process of heating.When the sodium sulfate content is 5.0％,the salt-frost heave rate of the soil reaches a maximum of 2.5％.Using scanning electron microscopy,it can be found that silty sulfate soils will settle under their own weight after freeze-thaw cycles,and internal salt re-crystallization is the main reason for inhibiting settlement and even causing soil expansion.