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Experimental study on the characteristics of cryostructure and frost heave of
clay under one-dimensional freeze-thaw

3
1
1，2 ，YU Qihao ，WANG Jinguo ，
REN Xiuling
3 1，2 1
ZHANG Dongming ，ZHANG Zhenyu ，WANG Xinbin
（1. State Key Laboratory of Frozen Soil Engineering，Northwest Institute of Eco-Environment and Resources，
Chinese Academy of Sciences，Lanzhou 730000，China；
2. University of Chinese Academy of Sciences，Beijing 100049，China；
3. Yalong River Hydropower Development Company，Ltd，Chengdu 610065，China）

Abstract：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.
Keywords：clay；repeated freeze-thaw；water migration；initial moisture content；cooling temperature；num⁃
ber of freeze-thaw cycles

（责任编辑：耿庆斋）

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