关键词: 人工冻结, 冻胀效应, 盾构对接, 地层压缩, 模型试验

Abstract: In general, uneven frost heave deformation was generated in upper soil strata during the freezing reinforcement process of shield junction, which was caused by the frost heave effect of the irregular frozen wall. Hence, this study was to obtain the influence law of strata deformation caused by the frost heave effect. Based on the similarity theory, a model test was carried out according to the prototype of the freezing reinforcement project of shield junction in Shanghai, and then the deformation data were analyzed. The results show that the upper strata deformation caused by the frost heave increases linearly with increasing the frozen wall thickness in the freezing process. When the development of the freezing wall exceeded the measuring point, the stratum deformation at the corresponding position no longer changed. It is found that the frost heaving force caused by the frost heave extrudes the upper strata in the freezing process, which increases both the strata deformation and its average strain with increasing the depth of measuring points. When the frost heave force exceeds the cohesion of soil, the growth of the average strain terminates due to the slide occurrence in upper soil layers. Moreover, the strata are no longer subjected to compress, and the deformation of the bottom stratum transfers directly to the upper strata. The results indicate that the frozen wall thickness is the primary factor and the formation depth is a secondary factor, which both affect the upper strata deformation .

Key words: artificial ground freezing, frost heave deformation, shield junction, formation compress, model test