冬灌区粉砂的反复冻融效应  

Effects of Repeated Freeze-thaw on Silt in Winter Irrigation District

作　　者：李剑[1] 潘鹏[1] 崔自治[1] 郝佳兴[1] LI Jian PAN Peng CUI Zi- zhi HAOJia-xing(College of Civil and H y d r a u l i c E n g i n e e r i n g , N i n g x i a Uni v e r s i t y , Yinchuan 750021, P. R . China)

机构地区：[1]宁夏大学土木与水利工程学院,银川750021

出　　处：《科学技术与工程》2017年第14期268-272,共5页Science Technology and Engineering

基　　金：教育部"长江学者和创新团队发展计划"创新团队项目(IRT1067)资助

摘　　要：结合宁夏当地气候和冬灌区粉砂的区域特点,以含水率和冻融循环次数为因素,应用封闭系统一维冻融试验方法,研究了粉砂冻胀、融沉和压缩性的冻融效应,分析了压缩性的冻融效应与冻融变形的相关性。结果表明:粉砂的冻胀率、融沉系数和压缩系数增量均随冻融循环次数的增加而增大,在前几次冻融循环内变化剧烈,随后趋于平缓,一定冻融循环后达到稳定。其达到稳定的冻融循环次数与含水率有关,随含水率的增大而增大。含水率使冻融循环效应增大,冻融循环使含水率效应提高。压缩系数增量与冻融变形率间存在非常好的线性相关性,且与理论分析吻合。研究结果对宁夏冬灌区砂土地基工程冻害评价与防治具有重要的指导意义。Combined witli the regional characteristics of the local climate and silt in Ningxia winter irrigationdistrict, witli factors such as water content and freeze-tiiaw cycles, effects of freeze-thaw thawing settlement and compression of silt were studied by one-dimensional freeze-thaw test method, and thecorrelation between freeze-thaw effect on compression and the freeze-thaw deformation of saturated loess wasanalyzed. Results show that the frost heaving ratio, thawing settlement coefficient and increment of compression coefficient of silt increase with the increase of freeze-thawcycle, change dramatically in the previous several times of freeze-thaw cycles, and then tend to be gentle, after a certain freeze-thaw cycle achieve stability. T h e number offreeze-tiiaw cycles for t hem to achieve stability is related to the water content, and it increases witii the increase ofthe water content. Wa t e r content makes the effect of freeze- tliaw cycle increase, and freeze-thawcycle m a k e s theeffect of water content improve. There is a perfect linear correlation between increment of and freeze-thaw deformation rate, which is coincided with the theoretical analysis. T h e results have importantguiding significance for the evaluation and prevention of frost damage of engineering on sand soil foundation inNingxia winter irrigation district.

关 键 词：岩土工程 粉砂 反复冻融 压缩性 

分 类 号：TU443[建筑科学—岩土工程]