含钙质胶结地层某地铁联络通道冻结施工温度场变化与地面变形规律
叶青1郜新军2何况3苏庆辉2张庆欣4周凤印3
Variation of Temperature Field and Ground Deformation Law during A Metro Link Passage Freezing Construction in Calcareous Cemented Stratum
YE Qing1GAO Xinjun2HE Kuang3SU Qinghui2ZHANG Qingxin4ZHOU Fengyin3
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作者信息:1.中铁十一局集团有限公司， 430061， 武汉；
2.郑州大学土木工程学院， 450001， 郑州；
3.郑州地铁集团有限公司， 450047， 郑州；
4.新疆昆仑工程咨询管理集团有限公司， 830063， 乌鲁木齐
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Affiliation:1.China Railway 11th Bureau Group Co., Ltd., 430061, Wuhan, China;
2.School of Civil Engineering, Zhengzhou University, 450001, Zhengzhou, China;
3.Zhengzhou Metro Group Co., Ltd., 450047, Zhengzhou, China;
4.Xinjiang Kunlun Engineering Consulting Management Group Co., Ltd., 830063, Urumqi, China
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关键词:
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Key words:
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DOI:10.16037/j.1007-869x.20246190
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中图分类号/CLCN:TU433； TU472.9
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栏目/Col:土建工程
摘要:
［目的］不同富水地层采用冻结法施工时，冻结土体表现出的冻结特性各不相同。有必要基于郑州某地铁联络通道冻结法施工过程，研究典型含钙质胶结地层冻结施工温度场变化及地面变形的规律。［方法］基于郑州某地铁联络通道冻结施工项目，阐述伞骨状冻结孔及测温孔布置方案，对冻结开挖及融溶期间盐水温度、测温孔温度，以及联络通道正上方及邻近位置地面监测点竖向位移进行了现场实测，基于实测数据分析了冻结施工温度场变化及地面变形的规律。［结果及结论］冻结期间，各测温孔在冻结期间温度下降趋势基本相同，分为急速降温阶段、相变阶段、二次降温阶段、冻结稳定阶段4个阶段。在急速降温阶段，入土较浅的测点降温比较深测点快；但在二次降温阶段则与之相反。在释放潜热时，入土较深测点用时是入土较浅测点用时的30倍。在含钙质胶结地层，不同入土深度测点的土体温差较小，但粉质黏土地层不同深度测点温差较大。开挖期间，联络通道正上方及邻近位置地面监测点竖向位移变化较大；融沉期间，联络通道中轴线断面及上方邻近土体融沉较大，需加强此处的融沉注浆。
Abstracts:
［Objective］ When the AGF (artificial ground freezing) method is applied in different water-rich strata, the freezing characteristics of the frozen soil vary significantly. It is therefore necessary to study the variation of the temperature field and ground deformation law during the freezing construction process in a typical calcareous cemented stratum, for a metro line link passage freezing project in Zhengzhou City. ［Method］ Based on the above project in Zhengzhou, the arrangement plan of umbrella-shaped freezing holes and temperature measurement holes is described. Field measurements are conducted for brine temperature, measuring point temperature, and vertical displacement at ground monitoring points directly above and adjacent to the link passage during freezing excavation and thawing periods. The variation of the temperature field and the ground deformation law during freezing construction are analyzed based on the measured data. ［Result & Conclusion］ During the freezing period, all temperature measurement holes exhibit a similar temperature drop trend, which can be divided into four stages: rapid cooling stage, phase transition stage, secondary cooling stage, and stable freezing stage. In the rapid cooling stage, shallowly embedded measuring points will cool faster than deeper ones, whereas the opposite is observed during the secondary cooling stage. During latent heat release, the time required for deeper measuring points is three times that of shallower ones. In calcareous cemented strata, the temperature difference between different depth measurement points in soil is relatively small, while in silty clay strata, the temperature difference is significantly larger across depths. During excavation, vertical displacement at monitoring points above and adjacent to the link passage varies considerably. During thaw settlement, substantial settlement occurred in the soil near the link passage central axis and its overlying region, indicating the need to reinforce grouting in this area to control thaw-induced settlement.
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