Abstract:

In order to solve the problem of shield receiving in complex surrounding environment and soft waterrich condition, the combined method of Rodin jet pile (RPJ) method and freezing method are put forward based on end soil reinforcement of a metro station on Tianjin Metro Line No. 5. The reinforcement scheme and technological parameters are presented by combining theoretical calculation and engineering practice; and the frozen soil temperature and settlement of ground surface and pipelines are monitored and analyzed. The study results show that: (1) The center temperature of a thermometer hole is lower than surrounding one; the inner ring temperature is lower than outer one at same depth of thermometer hole; and the frozen soil wall develops from middle to both ends and from inner ring to outer ring. (2) Obvious displacement does not occur to pipelines during soil freezing and unfreezing period, which indicates that the soil improvement can effectively control freezinginduced thawing settlement. (3) The maximum settlements of ground surface and pipelines are 17.4 mm and 6.2 mm, respectively, which meet relevant requirements and illustrate the rationality and feasibility of the combined method of RPJ and freezing method.

Key words: shield receiving, end soil reinforcement, Rodin jet pile (RJP) method, freezing method, frost heave, thaw settlement