冻融作用下水泥改良软黏土的性能演化过程
发布时间：2018-11-26 12:29
【摘要】：以天津滨海新区的软黏土为研究对象,制备了4种初始含水率的水泥改良软黏土试样,并对其进行了不同冻融循环次数下的无侧限抗压强度(UCS)试验和孔隙分析.结果表明:随着冻融循环次数的增大,试样的无侧限抗压强度逐渐减小,强度衰减主要集中在前期1~3次冻融循环过程中;相同冻融循环次数作用下,试样初始含水率越大,其强度损失率越大;试样的孔隙分布特征受冻融循环次数和初始含水率影响,随初始含水率增大,其孔隙分布逐渐由小孔隙分布区向较大孔隙分布区演变;低饱和度状态下,冻融会引起土体局部孔隙收缩,但同时诱发裂隙产生;高饱和度状态下,冻融会引起土体结构疏松.总体而言,冻融循环作用会引起水泥改良软黏土细观结构发生明显损伤,最终导致其宏观力学强度逐渐衰减.因此,在工程实践中需要进一步关注水泥改良软黏土的后期强度,并严格控制其初始填筑时的湿度状态.
[Abstract]:Taking the soft clay in Tianjin Binhai New area as the research object, four kinds of cement modified soft clay samples with initial moisture content were prepared, and their unconfined compressive strength (UCS) test and pore analysis were carried out under different freeze-thaw cycles. The results show that with the increase of freeze-thaw cycles, the unconfined compressive strength of the samples decreases gradually, and the strength attenuation is mainly concentrated in the early stage of 1 ~ 3 freeze-thaw cycles. Under the same freeze-thaw cycles, the higher the initial moisture content, the greater the strength loss rate. The pore distribution of the sample is affected by the number of freeze-thaw cycles and the initial water content. With the increase of the initial water content, the pore distribution evolves from the small pore distribution area to the larger pore distribution area. Under the condition of low saturation, freezing and thawing will cause shrinkage of local pores in soil, but at the same time, it will induce cracks, and at high saturation, freezing and thawing will lead to loose structure of soil. In general, the freezing and thawing cycle will cause obvious damage to the microstructure of the cement modified soft clay, and eventually lead to the gradual decline of the macroscopic mechanical strength of the soft clay. Therefore, in engineering practice, it is necessary to pay more attention to the later strength of cement modified soft clay, and strictly control the humidity state of its initial filling.
【作者单位】： 三峡大学三峡库区地质灾害教育部重点实验室;宜昌朗天新型建材有限公司;
【基金】：湖北省自然科学基金资助项目(2014CFB664) 国家自然科学基金资助项目(51579137)
【分类号】：TU43
本文编号：2358562
[Abstract]:Taking the soft clay in Tianjin Binhai New area as the research object, four kinds of cement modified soft clay samples with initial moisture content were prepared, and their unconfined compressive strength (UCS) test and pore analysis were carried out under different freeze-thaw cycles. The results show that with the increase of freeze-thaw cycles, the unconfined compressive strength of the samples decreases gradually, and the strength attenuation is mainly concentrated in the early stage of 1 ~ 3 freeze-thaw cycles. Under the same freeze-thaw cycles, the higher the initial moisture content, the greater the strength loss rate. The pore distribution of the sample is affected by the number of freeze-thaw cycles and the initial water content. With the increase of the initial water content, the pore distribution evolves from the small pore distribution area to the larger pore distribution area. Under the condition of low saturation, freezing and thawing will cause shrinkage of local pores in soil, but at the same time, it will induce cracks, and at high saturation, freezing and thawing will lead to loose structure of soil. In general, the freezing and thawing cycle will cause obvious damage to the microstructure of the cement modified soft clay, and eventually lead to the gradual decline of the macroscopic mechanical strength of the soft clay. Therefore, in engineering practice, it is necessary to pay more attention to the later strength of cement modified soft clay, and strictly control the humidity state of its initial filling.
【作者单位】： 三峡大学三峡库区地质灾害教育部重点实验室;宜昌朗天新型建材有限公司;
【基金】：湖北省自然科学基金资助项目(2014CFB664) 国家自然科学基金资助项目(51579137)
【分类号】：TU43
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