摘要
人工冻结技术可以短期提升地层稳定性并隔绝地下水,是在江底构建临时盾构检修环境的有效方法,而已有研究成果尚无法对冻结施工过程的评价提供参考。依托南京市新济洲越江供水廊道工程,研究了盾构泥水仓内形成冻土过程中温度分布特征及影响规律。结果表明:通过盾构工作面的接力换热装置,可将地面低温盐水以较小循环压力输入冻结管,从而降低冻结管内盐水渗漏风险,在稳定冻结阶段工作面盐水温度较地面温度偏高约2.5℃;施工过程中冻结管端头温度的变化过程基本一致,但受到冻结管周围地层吸热能力差别的影响,间距较大位置的冻结管端头温度偏高约1℃;盾构结构钢材导热性能和散热系数的差别会影响冷量传递过程,造成盾构刀盘周围位置的冻土温度偏低3℃左右,而盾构面板的散热导致相应位置的冻土温度偏高约4℃;在水平冻结管最大布置间距3.12 m的条件下,冻结80 d时可将盾构泥水仓全部冻实,从而具备打开盾构泥水仓进行盾构应急检修的施工条件。
It is an effective method to construct a temporary shield maintenance environment at the bottom of rivers by isolating connection with the external groundwater after horizontal freezing in the shield mud tank.However,the existing research results cannot provide a reference for the evaluation of the freezing construction process.Based on the cross-river water supply corridor project of Xinjizhou in Nanjing,the temperature distribution characteristics and influence law in the process of forming frozen soil in shield mud tank were studied.The results show that through the relay heat exchanger of the shield working face,the ground low-temperature brine can be pumped into the freezing pipe with a small circulating pressure,thereby reducing the risk of brine leakage in the freezing pipe.During the stable freezing stage,the brine temperature of the working face was about 2.5℃higher than the ground temperature.The change process of the temperature at the end of the freezing pipe during the construction process is basically the same,but due to the difference in the heat absorption capacity of the strata around the freezing pipe,the temperature at the end of the freezing pipe with a large spacing was about 1℃higher.The difference between the thermal conductivity and the heat dissipation coefficient of the shield structure steel will affect the cold transfer process,resulting in the temperature of the frozen soil around the shield cutterhead about 3℃lower,while the heat dissipation of the shield panel causes the temperature of the frozen soil at the corresponding position about 4℃higher.Under the condition that the maximum spacing of the horizontal freezing pipe was 3.12 m,the shield mud tank can be frozen completely after 80 days of freezing,so that the construction conditions for opening the shield mud tank in emergency maintenance can be realized.
作者
石湛
章铁军
李美香
伯音
陈时光
石荣剑
SHI Zhan;ZHANG Tiejun;LI Meixiang;BO Yin;CHEN Shiguang;SHI Rongjian(Changjiang Survey,Planning and Design Research Co.,Ltd.,Wuhan 430014,China;Nanjing Jiangning District Embankment Reservoir Management Institute of Jiangning District,Nanjing 211103,China;China Construction Eighth Engineering Bureau Co.,Ltd.,Shanghai 200122,China;School of Mechanics and Civil Engineering,China University of Mining and Technology,Xuzhou 221116,China)
出处
《人民长江》
北大核心
2024年第10期157-165,共9页
Yangtze River
基金
国家自然科学基金项目(5210838)
湖北省青年自然科学基金项目(2024AFB518)。
关键词
富水地层
泥水平衡盾构
冻结温度场
越江供水廊道工程
water-rich stratum
mud-water balance shield
freezing temperature field
cross-river water supply corridor project
