近年来,国外主要工业国家在地下建筑工程中使用了液氮冻结,显示了这种新冻结方法的工艺设备简单和低温快速的特点。我国于79年4月进行了首次试验,基本达到预期效果。 液氮冻结在工艺设备,冻土温度,扩展速度等方面都与一般盐水冻结不同。本文除扼要分析上述问题外,着重探讨液氮冻结的冻结时间。 In recent years, major industrial countries in foreign countries in the underground construction of the use of liquid nitrogen freezing, showing the new freezing method of the process equipment is simple and low temperature fast features. Our first trial in April 1979 basically achieved the desired results. Liquid nitrogen freezing in the process equipment, frozen soil temperature, expansion speed and other aspects of the general freezing of salt is different. In addition to a brief analysis of the above problems, this paper focuses on freezing time of liquid nitrogen freezing.