摘要
试验结果表明,土柱端面温度周期变化,导致土柱中冻融界面上下移动,这是成冰的必要条件。由于真空渗透机制,水分被抽吸到冻融界面附近并在那里成冰。有外界水源补给是成冰的充分条件。它导致反复冻融循环时冰层厚度不断增加。冰层的位置和厚度取决于冻融界面的位置和冻融循环的次数。如果每次冻融循环后,冻融界面的位置保持不变,则形成较厚的冰层。在每次冻融循环中,如果融化深度大于冻结深度,则只能形成一层薄冰层。反之,如果融化深度小于冻结深度,则经多次冻融循环后,可以形成多层薄冰层。
To study the conditions of ice formation during soil freezing and thawing, the controlled freezing and thawing test on the saturated sand was conducted in the laboratory. The results have shown that the temperatue at the end of the soil column changing periodically, which induces the freezing-thawing surface in the soil column moving up and down, is the necessary condition for ice formation. By the mechanism of vacuum and permeableness water is adsorbed to the place nearby the freezing-thawing surface and ice formed. Having water supply from the outside of the soil column is the ample condition for ice formation. It results the thickness of ice layer continuously increasing in freezing and thawing cycles. The location and the thickness of ice layer depend on the location of freezing-thawing surface and the times of freezing and thawing cycles. If the freezing-thawing surface keeps constant after each freezing and thawing cycle, then the thicker ice layer will be formed. In each freezing and thawing cycle, if the thaw depth is greater than the frost depth, then only one thin ice layer can be formed and contrarily, if the thaw depth is less than the frost depth, then multiple thin ice layers will be formed after many times of freezing and thawing cycles.
出处
《冰川冻土》
CSCD
北大核心
1992年第2期101-106,共6页
Journal of Glaciology and Geocryology
基金
国家自然科学基金资助项目
关键词
砂土
饱水
冻融
成冰
freezing and thawing cycle, freezing-thawing surface, ice formation, mechanism of vacuum and permeableness
