文章摘要
任秀玲,俞祁浩,王金国,张东明,张振宇,王新斌.黏土单向冻融作用下冷生构造及冻胀特性试验研究[J].水利学报,2021,52(1):81-92
黏土单向冻融作用下冷生构造及冻胀特性试验研究
Experimental study on the characteristics of cryostructure and frost heave of clay under one-dimensional freeze-thaw
投稿时间:2020-04-08  修订日期:2020-10-29
DOI:10.13243/j.cnki.slxb.20200234
中文关键词: 黏土  反复冻融  水分迁移  初始含水率  冷冻温度  冻融次数
英文关键词: clay  repeated freeze-thaw  water migration  initial moisture content  cooling temperature  num- ber of freeze-thaw cycles
基金项目:国家自然科学基金项目(41772325,41801039);雅砻江流域水电开发有限公司科学技术项目(LHKA-G2019006);青藏高原二次科考项目(2019QZKK0905)
作者单位E-mail
任秀玲 中国科学院 西北生态资源环境研究院, 甘肃 兰州 730000
中国科学院大学, 北京 100049 
 
俞祁浩 中国科学院 西北生态资源环境研究院, 甘肃 兰州 730000 yuqh@lzb.ac.cn 
王金国 雅砻江流域水电开发有限公司, 四川 成都 610065  
张东明 雅砻江流域水电开发有限公司, 四川 成都 610065  
张振宇 中国科学院 西北生态资源环境研究院, 甘肃 兰州 730000
中国科学院大学, 北京 100049 
 
王新斌 中国科学院 西北生态资源环境研究院, 甘肃 兰州 730000  
摘要点击次数: 563
全文下载次数: 693
中文摘要:
      研究黏土的水分迁移特性,对评估冻融作用对填筑土料的工程影响意义重要。以两河口水电站大坝心墙的填筑土料黏土为研究对象,针对冬季施工现场日循环冻融作用的环境特点,在室内模拟开展封闭系统下短时、高频、浅冻结条件下的单向冻融试验,研究了反复冻融作用下试样的冷生构造、水分迁移和冻胀特性。结果表明:黏土在日变化冻融作用下,试样受影响区域会有分凝冰快速发育,并随冻融条件的变化形成垂直于冻结方向、形态和厚度各异的薄层状冷生构造,并与以往研究存在显著区别。其中,与以往研究相比,受冻融影响区域分凝冰层厚相对较薄、且较为均匀,空间分布差异性表现为下部区域分凝冰的平均层厚相对上部略厚,但分凝冰层的数量增多。该种特性受初始含水率、冷冻温度、冻融次数等影响较大。其中,初始含水率对分凝冰厚度的变化影响最大。冷冻温度对层状冷生构造的发育和分布影响较大,-5℃冷冻温度下,冷生构造的发育程度最为突显;而在-10℃冷冻温度下,分凝冰层厚度和层状冷生构造的分布都较为均匀。冻融作用对层状冷生构造的影响表现为累积过程,冻融次数的增加使分凝冰层数量增多。另外,试样冻胀量较小,受冻融影响区域下部分凝冰起主要贡献作用。研究结果为季节冻土区大坝冬季施工过程的冻融防控具有重要指导作用。
英文摘要:
      Studying the water migration characteristics of clay is of great significance for assessing the engi- neering impact of freeze-thaw on the filling soil. Taking clay which is the important filling soil of the dam core wall of the Lianghekou Hydropower Station in China as the research object,and according to the envi- ronmental characteristics of daily cycle freezing-thawing effect on the construction site in winter, a series of repeated one-dimensional freeze-thaw experiments with short-time, high-frequency and shallow freezing conditions under a closed system are carried out indoor, and the characteristics of ice lens, water migra- tion and frost heave of soil under repeated freeze-thaw effect are studied. The results indicate that under the diurnal freeze-thaw effect, ice lens will be quickly formed in the affected part of soil, and with the change of freeze-thaw conditions,thin-layered ice lens which are obviously perpendicular to the freezing di- rection and with different morphology and thickness are formed, which are significantly different from previ- ous studies. Among them, compared with the previous research, the thickness of ice lens is relatively thin and uniform in the part where is affected by freeze-thaw. The difference in spatial distribution is that the average thickness of ice lens in the lower part is thicker than that in the upper part, but the number of ice lens increases. This characteristics are greatly affected by the initial moisture content, cooling tempera- ture and the number of freeze-thaw cycles. Among them,the initial moisture content has the greatest influ- ence on the change of the thickness of ice lens. Cooling temperature has a great influence on the develop- ment and distribution of the layered cryostructure. The development degree of cryostructure is most promi- nent at a cooling temperature of -5℃,while both the thickness of ice lens and the distribution of the lay- ered cryostructure are more uniform at the cooling temperature of -10℃. The effect of freeze-thaw on the layered cryostructure is a cumulative process, and the number of ice lens increases with the increase of the number of freeze-thaw cycles. In addition,the amount of frost heave of soil is small,and the ice lens in the lower part of soil where is affected by freeze-thaw plays a major role. The research results have im- portant guiding effects on the prevention and control of freeze-thaw process in the winter construction of dams in seasonally frozen soil areas.
查看全文   查看/发表评论  下载PDF阅读器
关闭