细粒硫酸钠盐渍土盐冻胀特性试验研究

Experimental study of salt-frost heave characteristics of fine-grained sodium sulfate saline soil

为探究温度与硫酸钠含量对细粒硫酸钠盐渍土盐冻胀率及盐胀占比的影响,取兰州黄土作为素土人工配盐,用平衡公式进行理论推导,并设计了室内试验对其进行验证。结果表明:当压实度为92%、含水率为最优含水率16.8%时,细粒硫酸钠盐渍土的冻结温度随硫酸钠含量的增大而降低,且随着温度的降低,盐胀率与盐冻胀率的变化趋势基本一致。在冻结温度以下至-5℃盐胀发展速度最快,在-5℃以下盐胀率增长很小。在压实度为92%、含水率为最优含水率16.8%条件下,在硫酸钠含量不变时,温度越低,盐胀占比越大;温度不变时,硫酸钠含量越高,盐胀占比越大,在冻结温度以上盐胀占比为100%,但当温度降至-3^-4℃时盐胀占比降到50%,在-10℃以下盐胀占比基本保持不变。

In order to explore the influence of temperature and sodium sulfate content on the salt-frost heave ratio and proportion of salt heave in fine-grained sodium sulfate saline soil,Lanzhou loess was taken as plain soil to prepare specimens mixed salt artificially for testing.The results showed that when the compaction degree is 92%and the moisture content is the optimal moisture content of 16.8%,the freezing temperature of the fine-grained saline soil decreases with the increase of the sodium sulfate content,and with the decrease of the temperature,the change trend of salt heave ratio is basically consistent with the salt-frost heave ratio.From freezing point to-5℃,the salt heave ratio is significant,and below-5℃salt heave ratio less increases.When the compaction degree is 92%and the moisture content is 16.8%,the lower the temperature is,the larger the salt heave ratio will be when the sodium sulfate content is constant.At constant temperature,the higher the content of sodium sulfate,the more the salt heave ratio;above the freezing point,the salt heave ratio will be 100%.As the temperature drops to-3--4℃,the salt heave ratio will drop to 50%,and salt heave ratio will be constant as the temperature is lower than-10℃.