非补水条件下同心压实黄土的冻融特性

为揭示宁夏压实黄土在非补水条件下的冻融特性,结合当地地域特点,设计正交试验方案,采用封闭系统一维单向冻融试验方法,研究了宁夏压实黄土的冻胀融沉变形随压实度、饱和度和冻融循环次数变化的规律,建立了冻胀率、融沉系数与压实度、饱和度和冻融循环次数的关系模型。结果表明：非补水条件下,冻融循环对压实黄土的冻融变形有明显影响,饱和度越大,影响越明显；饱和度<40%时,试样表现为冻缩融胀现象,且压实度越大,冻缩融胀越明显；冻胀率与融沉系数均随压实度的增大而减小,随着饱和度的增大呈非线性增大；压实度和饱和度对冻融变形的影响非常显著,尤其是饱和度的影响,饱和度由40%增加至85%,冻胀率最大增量约5%；建立的冻胀率和融沉系数的模型显著性高,与各因素有很好的相关性,可用于预测封闭系统非补水条件下压实黄土的冻融变形。

Freezing and thawing characteristics of concentric compacted loess under non-hydration conditions

In order to reveal the freeze-thaw characteristics of compacted loess in Ningxia under non water supply conditions, combined with the characteristics of local area, the orthogonal experimental scheme was designed, and the one-dimensional unidirectional freeze-thaw test method used closed system, the variation of freeze-thaw deformation was studied, relation model between frost heaving ration, thawing settlement coefficient and saturation, compaction, freeze-thaw cycles was established. The results show that under non water supply conditions, the freeze-thaw cycle has a significant effect on the freeze-thaw deformation of compacted loess. When the saturation is less than 40%, the sample shows the phenomenon of freeze-shrinkage, the frost heave ratio and the thawing coefficient decrease with the increase of compaction degree, and increase nonlinearly with the increase of saturation, compactness and saturation the effect of degree on freeze-thaw deformation is very significant, especially the effect of saturation , the saturation increases from 40% to 85%, the maximum increase of frost heave rate is about 5%, The established model of frost heaving rate and melting coefficient is highly significant, which can be used to predict the freeze-thaw deformation of compacted loess under the condition of no water supply with closed system.