双线冻结隧道下穿车站冻胀特性模型试验与工程实测

为保证双线隧道冻结下穿施工中上部结构安全,需对冻结下穿过程中的冻胀规律进行深入研究以得出最优施工方案。基于上海地铁18号线双线隧道冻结下穿地铁10号线国权路车站工程,开展模型试验和工程实测,研究了上覆车站底板在全长冻结和分段冻结两种模式下的冻胀规律。结果表明：分段冻结模式对上覆结构产生的最大抬升量为20.5 mm,其出现在第二条隧道冻结期间,小于全长冻结模式产生的最大抬升量30 mm。车站底板在分段冻结模式下产生整体抬升,第二条冻结隧道在积极冻结期间的抬升速度为0.12 mm/d,大于第一条隧道冻结时的抬升速度0.08 mm/d。实际工程中采用取土卸压等方法降低冻胀量,得出车站底板最大抬升量为25.41 mm。试验得出的车站底板抬升规律与施工数据呈现较好的一致性,有效的指导了工程施工。

Experiment and Engineering Measurement of Frost Heave Characteristics of the Frozen Double-track Tunnel Underpass an Operation Station

To ensure the construction safety in a project of the frozen double-track tunnel underpass an upper structure, it is necessary to research the frost heave law caused by different conditions in advance during the underpass construction processes. Taking the double-track tunnel of Shanghai metro line No. 18 passing down the existing station of No. 10 line as the research object, a similar simulation experiment is carried out. The results show that, the maximum lift value of the upper structure generated by the segmental freezing occurred during the freezing period of the second tunnel, and the lift value is 20.5 mm, which is less than the value of full-length freezing mode. The base slab of the station is lifted as a whole mode of the segmental freezing mode, and the lifting speed of the second frozen tunnel during active freezing is 0.12 mm/d, which is greater than that of the first tunnel when it is frozen by 0.08 mm/d. In the actual project, methods such as coring is used to reduce frost heave, and it is concluded that the maximum lift value of the base slab is 25.41 mm. The lift law of the base slab obtained from the similar simulation experiment is in good agreement with the construction project data, which guides the construction of the project effectively.