The coupled moisture-heat process of a water-conveyance tunnel constructed by artificial ground freezing method

2021 ◽  
Vol 182 ◽  
pp. 103197
Author(s):  
Ming Li ◽  
Qinguo Ma ◽  
Xiaoxiao Luo ◽  
Haiqiang Jiang ◽  
Yongdong Li
Keyword(s):  
Heat Process ◽  
Freezing Method ◽  
Ground Freezing ◽  
Water Conveyance ◽  
Artificial Ground Freezing ◽  
Water Conveyance Tunnel

scholarly journals In situ monitoring of frost heave pressure during cross passage construction using ground-freezing method

2016 ◽  
Vol 53 (3) ◽  
pp. 530-539 ◽  
Author(s):  
Lei Han ◽  
Guan-lin Ye ◽  
Yuan-hai Li ◽  
Xiao-he Xia ◽  
Jian-hua Wang
Keyword(s):  
Pressure Gauge ◽  
Earth Pressure ◽  
In Situ Monitoring ◽  
Frost Heave ◽  
Freezing Process ◽  
Groundwater Levels ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

The artificial ground-freezing method has the dual effect of ground reinforcement and waterproof sealing, and the frozen curtain can be designed flexibly. It is widely used in the construction of cross passages for shield tunnels in soft ground with high groundwater levels. However, due to the lack of in situ monitoring data, it remains difficult to determine the frost heave pressure acting upon a tunnel. In this study, based on the use of an anti-freezing pad-type earth pressure gauge, in situ monitoring was carried out to measure the frost heave pressure acting upon tunnel segments during the construction of cross passages for the Shanghai Yangtze River Tunnel. The monitoring results show that the earth pressure acting upon the tunnel could decrease dramatically during freezing, and this kind of decrease can take place suddenly and unpredictably, which can be illustrated using the finite element method. The maximum measured frost heave pressure during freezing and cross passage excavation was approximately 0.2 MPa, which was much smaller than the predicted value. Combining the distribution of temperature in the ground and construction countermeasures, the observed phenomena are mainly related to three factors: water migration during the freezing process, the tunnel–ground interaction, and the countermeasure of pressure release holes. The tunnel showed a horizontal extension–deformation, which was consistent with the releasing frost heave pressure acting upon it.

Properties of Frozen Soils for Cross Passage Construction in Line 1 and 2 of Wuxi Metro

2013 ◽  
Vol 353-356 ◽  
pp. 1662-1665 ◽  
Author(s):  
Xiang Dong Hu ◽  
Yan Guang Han
Keyword(s):  
Mechanical Properties ◽  
Laboratory Tests ◽  
Freezing Point ◽  
Frozen Soil ◽  
Frost Heave ◽  
Soil Test ◽  
Frozen Soils ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

Artificial ground freezing method (AGF) was applied in cross passage constructing of line 1 and 2 of Wuxi Metro. Mechanical properties of frozen soils such as uniaxial compressive strength, modulus of elasticity, Poissons Ratio, frost heave rate and freezing point are prerequisite for design and construction of AGF. In order to obtain the parameters mentioned, laboratory tests were conducted. One was the basic geotechnical test. Another was the frozen soil test.

scholarly journals Advanced ground freezing method and its applications in underground construction

2019 ◽  
Vol 265 ◽  
pp. 04021
Author(s):  
Mikhail Shuplik ◽  
Petr Nikolaev
Keyword(s):  
Urban Areas ◽  
Ground Improvement ◽  
Solid Carbon ◽  
Underground Construction ◽  
Solid Carbon Dioxide ◽  
Freezing Method ◽  
Ground Freezing ◽  
Improvement Method ◽  
Artificial Ground Freezing ◽  
Construction Works

During underground construction works in complex geological environment, special ground improvement techniques have to be used. One of them is artificial ground freezing (AGF). It can be applied in diverse projects in dense populated urban areas that place constraints on an application of other ground improvement methods. In Russia in the late 1980th was developed one new method of ground freezing. It uses solid carbon dioxide (SCD) that is loaded directly into freeze pipes, where it sublimates. As the result, the quite low temperature of freezing can be achieved easily. In this article are discussed several first application cases of this method. The results of these projects allow SCD freezing became widely used ground improvement method in Russia.

scholarly journals Application of Artificial Ground Freezing Technology in Modern Urban Underground Engineering

2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Yi Qi ◽  
Jinxun Zhang ◽  
Hao Yang ◽  
Yongwei Song
Keyword(s):  
Water Surface ◽  
Large Scale ◽  
Freezing Process ◽  
Physical Model Test ◽  
Group Effect ◽  
Underground Engineering ◽  
Sandy Gravel ◽  
Freezing Method ◽  
Ground Freezing ◽  
Artificial Ground Freezing

Based on typical water-rich sandy gravel strata in Beijing, in order to explore the application of the artificial ground freezing method (AGF) in urban large-scale underground engineering, the formation and development of freezing body were analyzed when multirow freezing pipes were working together, and the group effect exhibited during the freezing process was also revealed in this paper. On this basis, the basin-shaped freezing method (BFM) is put forward as an application of AGF used in underground engineering. BFM structure consists of two parts: the frozen curtain (basin wall) around the excavation scope and the horizontal frozen body (basin bottom) at the bottom of the station. Physical model test and numerical simulation were conducted to study temperature field expansion of BFM under two different conditions. The results show the following: (1) The group effect refers to the cooling effect of different freezing pipes influencing each other during freezing process. Under the condition of still water, the group effect expands the freezing area, and it shows the gradual development of freezing from back water surface to front water surface under seepage condition. (2) BFM can effectively play the role of water proofing, and although different parts of basin structure show different frozen order under different conditions, both basin wall and basin bottom can form an effective thickness during the freezing process.

scholarly journals Influence of Different Freezing Modes on the Base Slab Displacement of an Upper Structure

2019 ◽  
Vol 10 (1) ◽  
pp. 27
Author(s):  
Lei Wang ◽  
Yanting Wang ◽  
Fangzheng Li ◽  
Zhiqiang Liu ◽  
Chunsheng Lu
Keyword(s):  
High Risk ◽  
Simple Formula ◽  
Frost Heave ◽  
Engineering Project ◽  
Simulation Experiments ◽  
Freezing Method ◽  
Ground Freezing ◽  
Similarity Ratio ◽  
Artificial Ground Freezing ◽  
Zigzag Shape

The high risk of metro tunnels that are underneath buildings in a water-rich layer has received much attention. The base slab of an upper structure deforms due to frost heave and settlement, which needs to be predicted before freezing and excavation. In this paper, simulation experiments with a similarity ratio of 1/25 were performed based on an engineering project where two tunnels underpass a running station through an artificial ground freezing method. The displacement of upper structures was analyzed under simultaneous and sequential freezing modes, with a simple formula proposed to estimate the frost heave in closely underpassing projects. It is shown that, under freezing and excavation stages, the base slab displacement displays a zigzag shape. These results are instructive to the construction of underpassing projects in a water-rich layer.

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