Wang Fan, Peng Shu-Quan, Chen Zai, Fan Ling, Li Yang
School of Civil Engineering, Central South University, Changsha 410075, China.
School of Resource Security Engineering, Central South University, Changsha 410083, China.
Sci Total Environ. 2023 Oct 10;894:165036. doi: 10.1016/j.scitotenv.2023.165036. Epub 2023 Jun 22.
Sulfate heave caused by salt swelling behavior poses a threat to engineering safety. The salt vertical distribution has a significant impact on the salt swelling behavior of sulfate-affected soils. A series of laboratory tests were conducted to explore the law of salt swelling and deformation of sulfate-affected soils under different salt vertical distributions. The results indicated that the salt swelling deformation mainly occurred in the initial rising and falling temperature stage. Residual accumulation formed as the salt swelling deformation increased over cyclic times. Salt swelling deformation increased with the increase in water content and salt-water ratio. The salt swelling deformation of sulfate-affected soils with a decreasing salt vertical distribution was larger than the other two forms. The maximum salt swelling also decreased as the water content and salt-water ratio reduced. In the 15 % water content samples with the vertical distribution of salt decreasing with depth, the maximum decrements were 34.78 %, 70.43 %, and 85.10 % as the salt-water ratio reduced, respectively. The sulfate-affected soils with the gradually decreasing salt distribution formed a great radial expansible strain. However, the soil with uniform salt distribution had a larger contractive strain. While the contractible strain increased with the reduction in water content, the expansible strain dropped. This work reveals the law of salt swelling deformation under the effect of salt vertical distribution, providing an important reference for subgrade engineering in sulfate-affected soils.
由盐胀行为引起的硫酸盐胀起对工程安全构成威胁。盐分的垂直分布对受硫酸盐影响土壤的盐胀行为有显著影响。开展了一系列室内试验，以探究不同盐分垂直分布情况下受硫酸盐影响土壤的盐胀及变形规律。结果表明，盐胀变形主要发生在温度升降的初始阶段。随着盐胀变形在循环次数中增加，形成了残余累积。盐胀变形随含水量和盐水比的增加而增大。盐分垂直分布递减的受硫酸盐影响土壤的盐胀变形大于其他两种形式。最大盐胀也随着含水量和盐水比的降低而减小。在含水量为15%且盐分垂直分布随深度递减的试样中，随着盐水比降低，最大减量分别为34.78%、70.43%和85.10%。盐分分布逐渐递减的受硫酸盐影响土壤形成了较大的径向膨胀应变。然而，盐分分布均匀的土壤具有较大的收缩应变。虽然收缩应变随着含水量的降低而增加，但膨胀应变却下降。本研究揭示了盐分垂直分布影响下的盐胀变形规律，为受硫酸盐影响土壤地区的路基工程提供了重要参考。
