摘要
钱塘江底地层富含气及动水,会明显影响江底联络通道冻结施工的温度场演变过程和分布特征。为解决该问题,通过对位于钱塘江底的杭州地铁6号线某联络通道冻结工程进行现场监测,研究冻结施工中不同位置地层温度的演变过程,分析停冻后冻结管内的温度变化特征,获得地层中含气及地下水流动对联络通道冻结温度场的影响规律。1)双侧发散布孔时,冻土向内平均发展速度是向外的1.47倍,而停冻6 h后外排和内排冻结管内的温度分别回升5℃和10℃;2)地层中囊状气泡削弱了冻结管向周围土体的冷量传递过程,从而明显影响冻结效果,冻结过程中气泡位置的温度比冻结管终端位置偏高8~18.4℃;3)地下水流动也会影响地层中的冷量分布,冻结57 d时冻结壁上、下游对应位置冻结管内温度相差8℃,而停冻6 h后相应位置的冻结管内温度分别回升了5℃和2℃。研究结果表明:双侧隧道内发散布孔方式可以有效解决含气及动水地层中影响联络通道冻结施工的问题,而地层中囊状气泡和地下水流动都会明显影响冻结温度场的分布特征。
The complex geological conditions of rich gas and dynamic water in the Qiantang river considerably affect the evolution and distribution characteristics of the temperature field during the freezing process of the connecting gallery.A case study is conducted on the in-situ monitoring of a freezing project at the connecting gallery of the Hangzhou metro line 6 in the Qiantang river.The process of formation temperature variation at different positions during the freezing process is investigated,and the temperature variation characteristics of the freezing pipe after freezing are analyzed to determine the influence of gas and groundwater flow on the freezing-temperature field of the connecting gallery.The main results are summarized as follows.(1)Under bilateral hole distribution,the average speed of frozen soil inward development is 1.47 times that of outward development.When the freezing is stopped for 6 h,the temperature in the outer and inner tubes increase by 5℃and 10℃,respectively.(2)The presence of bubbles hinders the cold transfer process of the freezing tube to the surrounding soil,thereby significantly affecting the freezing effect.The formation temperature at which bubbles exist during the freezing process is 8–18.4℃higher than that at end position of freezing tube.(3)Groundwater flow also affects the distribution of cooling capacity in the formation.After a frozen period of 57 d,the temperature difference between the upper and downstream positions in the freezing tube reaches 8℃.When the freezing is stopped for 6 h,the temperature in the freezing tube at the corresponding position increased by 5℃and 2℃,respectively.The results show that the bilateral divergently-arranged freezing tubes in tunnel can effectively mitigate the influence of gas and dynamic water on the formation of the freezing of the connecting gallery.Additionally,the bubbles in the formation and the flow of groundwater affect the distribution characteristics of the freezing-temperature field.
作者
孙枫
SUN Feng(Hangzhou Metro Group Co.,Ltd.,Hangzhou 310019,Zhejiang,China)
出处
《隧道建设（中英文）》
CSCD
北大核心
2024年第6期1214-1222,共9页
Tunnel Construction
关键词
人工冻结法
含气与动水地层
地铁联络通道
双侧发散布孔
冻结温度场
现场实测
artificial freezing method
gas-and water-bearing strata
metro connecting gallery
double-side divergently-arranged freezing pipes
freezing-temperature field
field test
