为了研究地铁隧道冻结工程中的冻结管形式选择和地表冻胀量控制问题,依托广州市轨道交通13号线北延线机场区间隧道冻结工程,采用了室内试验、现场实测、数值计算的方法,对保温工艺、形式和冻结孔间距、保温段长度、冻结时间对地表冻胀量的影响进行了研究。研究结果表明:冻结管采用保温材料隔热方式可有效实现局部冻结,但施工时保温材料需进行防水处理,防止因地下水进入保温材料造成导热系数增加;地表冻胀量与保温长度呈线性反比关系,且随孔间距的增大比例系数逐步减小,随冻结时间延长增大。根据实测数据、计算得到了适用于本工程工况的冻胀量预测公式;结合工程现场条件,分析了制冷能耗和冻胀量与孔间距的关系,提出了在保证地表冻胀量的前提下,尽量减少冻结孔间距达到缩减工期、能耗的目的。

Indoor test, on-site measurement, and simulation calculation are performed to investigate the effects of heat preservation process and form, freezing hole spacing, length of unfreezing section, and freezing time on surface frost heaving in the aim of researching the form of freezing pipes and surface frost heaving in subway tunnel freezing project. The freezing process of the airport segment tunnel of the north extension line of Guangzhou Rail Transit Line 13 is taken as the research background. Results show that partial freezing can be effectively achieved by using thermal insulation materials for freezing pipes, and the insulation materials should be waterproofed to prevent the thermal conductivity from increasing induced by groundwater. The frost heave on the surface is inversely proportional to the length of the insulation, and the proportional coefficient decreases with the increase of the hole spacing but increases with the extension of the active freezing time. The predictive equation of frost heave is presented. In addition, the distance of the freezing pipe can be reduced to cut the construction period and energy consumption under the premise of ensuring the surface frost heave.