Abstract: In order to reinforce the loose, high moisture and unstable strata in the underground engineering artificial freezing method was commonly used, and vertical straight layout of the frozen pipes was used frequently. However, the distribution and changes of temperature, stress and displacement were completely different from vertical circular layout, thereby induced engineering stability problems were paid less attention, which need further investigation both at home and abroad. On the basis of an inclined shaft freezing construction, the similarity criteria in the vertical straight freezing process were derived, which contained temperature field, stress field and moisture field, etc. Specific experiment program during the total process of soil freezing was designed detailedly. In self-made three-dimensional simulation freezing experiment system, 20 vertical frozen pipes were layout as 4×5 form. Stress environment and seepage condition were simulated as possible as field conditions. The value and change rate of soil temperature and horizontal frost heaving force were measured during the process of soil freezing. On this basis, the distribution of soil temperature and horizontal frost heaving force in different depth were investigated. Experiment results show that in vertical straight freezing, the impact of soil depth on the horizontal frost heaving force is significantly. In the same depth and ignoring the impact of other conditions, the value of frost heaving force and soil temperature are closely related; the change rate of frost heaving force mainly depends on the location of freezing front, which reaches its peak gradually by the distance close to freezing front; while the horizontal frost heaving force in frozen soil has stabilized with the development of freezing front.

Key words: vertical straight freezing, simulating experiment, horizontal frost heaving force, freezing front