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冰川冻土 ›› 1995, Vol. 17 ›› Issue (3): 250-257.

• 研究论文 • 上一篇    下一篇

温度和压力条件对正冻土中成冰过程和冷生组构的影响

王家澄, 徐学祖, 张立新, 王玉杰   

  1. 中国科学院兰州冰川冻土研究所冻土工程国家重点实验室, 730000
  • 收稿日期:1994-04-21 修回日期:1994-08-07 出版日期:1995-08-25 发布日期:2012-04-26

Influence of Temperature and Pressure on Cryogenic structure of Freezing soil

Wang Jiacheng, Xu Xiaozu, Zhang Lixin, Wang Yujie   

  1. State Key Laboralory of Frozen Soil Engineering, LIGG, CAS 730000
  • Received:1994-04-21 Revised:1994-08-07 Online:1995-08-25 Published:2012-04-26

摘要: 对内蒙古粘土在两种温度和压力的边界条件下进行了开放系统室内受控冻结试验。结果表明,相同温度边界条件下,上部荷载使土体压密、入流滞后、冰点降低、入流量小,导致分凝冰层数量少、厚度薄、冷生组构不发育;相同上部荷载条件下,冷端面温度持续下降的土拄,由于冻土段温度梯度持续增大,具有稳定入流且形成微冰层组构,而端面温度恒定的土柱中,由于冻土段温度梯度逐渐衰减,形成韵律式冷生剖面;外界水侵入压力增大了入流量,促进了冷生组构的发育。两种热边界条件诱导了指数型和直线型冻胀过程,两种给压方式诱导了衰减型和增长型冻胀量。关于上部荷载增大到某值,中断压力后冻胀终止的概念是相对的,即取决于热边界条件。

关键词: 温度, 压力, 正冻土, 成冰过程, 冷生组构

Abstract: The controlled freezing tests were conducted on Neimong clay in open system under twodifferent temperatures and pressures, respectively. Results show that the boundary tempera-tures control the freezing rate, temperature gradient, direction and rate and amount of watermigration. Thus it influences the rate of phase change of soil water,location and amount ofice foimation. The direction and magnitude of pressure influence the direction and amount ofwater migration and temperature of phase change. Thus it influences the degree of ice foma-tion. If the temperature boundary condition is the same,the cryogenic structure isunderdeveloped in layers and thickness of segregative ice,because the overburden pressureresults in densification of soil body,hysteresis of water intake flow, freezing point depressionand decreasing of amount of water intake flow.If the overburden pressure is the same,themicfo-layered and thin-layered ice strips are developed better in the soll column with the temperature decreashg linearly at cold end than with constant temperature, because thetemperature gradient is increasing with time in the fonner and decreasing in the latter. The in-jection pressure promotes the development of cryogenic structure by increasing the amount ofwater intake flow. Phase change of water results in frost heaving of freezing soll. The two heatboundary conditions induce the process of fros theaving as power and linear function of time,respectively.The two pressures induce frostheaving decreasing and increasing respectively. The concept of suspend pressure only has relative meaning because it depends on the heatboundary condition.

Key words: cryogenic structure, freezing soil, ice formation, pressure, temperature