冻胀融沉试验方法及粘土冻胀特性研究

发布时间：2018-04-08 15:11

本文选题：一维冻胀试验　切入点：等压冻胀试验　出处：《北京交通大学》2014年硕士论文

【摘要】：冻土区域在我国广泛分布,冻土病害问题突出,已经严重影响到了我国冻土地区的基础工程建设速度和地区发展。冻胀融沉是众多冻害中最为常见的,也较难处理的一种。目前有关冻土冻胀特性方面的研究不够成熟,在试验方法,冻胀机理,冻胀模型等多方面都有待深入和完善。本文针对土体冻胀特性的试验方法和冻胀机理,冻胀规律进行研究。本文的主要研究内容包括：1)建立土体冻胀的一维侧限和三维等压试验方法；2)开展一维侧限冻胀试验,通过正交试验研究土体成分、含盐量、土体含水量、土体初始干密度、冻融循环对土体体积变形的影响；3)开展三维等压冻胀试验,研究膨润土的冻胀机理；4)总结土样冻胀规律,建立了土体冻结过程中体积变化预测理论模型。通过研究,本文取得了以下成果和发现：1)建立了一维侧限冻胀试验的试验方法,并针对侧壁约束效应,提出了体积变形修正公式；2)设计并加工了温控体变仪,能够用于等压条件下的冻胀曲线测量；3)在冻胀试验中,发现粘土在冻结过程中,随饱和度增高,土体体变规律从收缩过度为膨胀。其机理可能在于孔隙水结晶胶结引起的收缩变形,和孔隙水结晶体体积膨胀引起的土体结构膨胀共同作用。基于此机理,本文给出了关于土样体积变化的简化预测模型。
[Abstract]:The frozen soil region is widely distributed in our country, and the problem of frozen soil disease is prominent, which has seriously affected the construction speed and regional development of the foundation engineering in the frozen soil region of our country.Frost heaving and thawing is one of the most common and difficult to deal with.At present, the research on frost heaving characteristics of frozen soil is not mature enough, and many aspects such as test method, frost heave mechanism and frost heave model need to be further improved.In this paper, the test method and mechanism of soil frost heaving are studied.The influence of freezing and thawing cycle on the volume deformation of soil mass. (3) the three-dimensional isobaric frost heave test was carried out, and the frost heave mechanism of bentonite was studied. 4) the frost heave law of soil sample was summarized, and the prediction model of volume change in soil freezing process was established.It can be used to measure the frost heave curve under isobaric condition. In the frost heave test, it is found that in the freezing process of clay, with the increase of saturation, the soil body changes from excessive shrinkage to expansion.The mechanism may lie in the shrinkage and deformation caused by pore water crystalline cementation and the expansion of soil structure caused by volume expansion of pore water crystals.Based on this mechanism, a simplified prediction model of soil sample volume variation is presented.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TU442

【参考文献】