Numerical interpretation of temperature distributions from three ground freezing applications in urban tunnelling

Pimentel, Erich; Papakonstantinou, Spyridon; Anagnostou, Georg

doi:10.1016/j.tust.2011.09.005

Cited by 137 publications

(35 citation statements)

References 2 publications

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“…Artificial ground freezing is currently the main method for the construction of shafts in water-rich soft soil layers. is method involves the construction of one or more loops of freezing pipes around a shaft wellbore; through continuous heat exchange between the low-temperature refrigerant in the freezing pipe and the frozen soil, the circulation of fluids results in a frozen wall with a certain strength and good sealing performance, providing a stable environment for the construction of the wellbore [1][2][3][4]. However, the increase of the groundwater flow velocity in the soil layer when the traditional freezing pipe arrangement scheme is adopted can lead to increased closure times or even failure to close.…”

Section: Introductionmentioning

confidence: 99%

Study on the Formation Law of the Freezing Temperature Field of Freezing Shaft Sinking under the Action of Large-Flow-Rate Groundwater

Wang

Rong

Lin

et al. 2019

Advances in Materials Science and Engineering

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Taking into account moisture migration and heat change during the soil freezing process, as well as the influence of absolute porosity reduction on seepage during the freezing process, we construct a numerical model of hydrothermal coupling using laws of conservation of energy and mass. The model is verified by the results of large-scale laboratory tests. By applying the numerical calculation model to the formation of artificial shaft freezing temperature fields under the action of large-flow groundwater, we conclude that groundwater with flow rates of less than 5 m/d will not have a significant impact on the artificial freezing temperature field. The maximum flow rates that can be handled by single-row freezing pipes and double-row freezing pipes are 10 m/d and 20 m/d, respectively, during the process of freezing shaft sinking. By analyzing the variation of groundwater flow rate during freezing process, we find that the groundwater flow velocity can reach 5–7 times the initial flow velocity near the closure moment of the frozen wall. Finally, in light of the action characteristics of groundwater on the freezing temperature field, we make suggestions for optimal pipe and row spacing in freezing pipe arrangement.

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Section: Introductionmentioning

confidence: 99%

Study on the Formation Law of the Freezing Temperature Field of Freezing Shaft Sinking under the Action of Large-Flow-Rate Groundwater

Wang

Rong

Lin

et al. 2019

Advances in Materials Science and Engineering

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“…The coolant enters into the freeze pipe and after reaching the deepest point of the inner pipe it returns and passes through the gap between the two pipes ( Figure 1). During the movement of the coolant in the gap, the refrigerant extracts heat from the surrounding ground [16]. [16] Understanding the mechanical behavior of the frozen soil is essential in the application of AGF and the construction project that follows.…”

Section: Introductionmentioning

confidence: 99%

“…During the movement of the coolant in the gap, the refrigerant extracts heat from the surrounding ground [16]. [16] Understanding the mechanical behavior of the frozen soil is essential in the application of AGF and the construction project that follows. Initial comprehensive studies on frozen soils [17][18][19] (Sayles 1968, Sayles and Haines 1974, Ting 1981) mainly focused on the creep behavior of frozen soils such as sand, silt and clay.…”

Section: Introductionmentioning

confidence: 99%

Experimental Study of the Mechanical Behavior of Frozen Soils - A Case Study of Tabriz Subway

Esmaeili‐Falak

Katebi

2017

Period. Polytech. Civil Eng.

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The mechanical properties of frozen ground are key parameters in design and implementation of artificial ground freezing (AGF) in underground projects. Soil samples were obtained from the urban underground railway project site in Tabriz, Iran. The specimens were classified as SP and CL according to the USCS. The specimens were remolded in accordance with the site conditions. Over 120 triaxial compression tests were conducted on the frozen samples at different temperatures, confining pressures and strain rates. The results show that the frozen SP and CL soils exhibit strain-softening and strain-hardening behaviour, respectively. In all cases, Young's modulus increases with decreasing temperature and increasing strain rate and confining pressure. Also, the shear strength increases with decreasing temperature and increasing strain rate. In all tests, the Young's modulus and shear strength of the SP soil are greater than the CL soil. Based on the results of this research, the application of artificial ground freezing was recommended for coarse-grained and non-cohesive soils like SP in the Tabriz underground railway project.

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“…e measured data from the temperature-measuring holes only reflect the temperature development at a certain location with time, so the analysis and prediction of the development of the whole freezing temperature field can be realized by means of finite element numerical simulation [18][19][20].…”

Section: Mathematical Models and Boundary Conditionsmentioning

confidence: 99%

Research and Application of the Local Differential Freezing Technology in Deep Alluvium

Wang

Rong

Cheng

et al. 2020

Advances in Civil Engineering

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Aiming at the complicated engineering conditions of the auxiliary shaft repair in the Banji coal mine, it was proposed to seal the water around the shaft lining by differential control freezing technology using double rows of holes. The outer row of holes is completely frozen, and the inner row of holes is local differential frozen according to the degree of destruction of the shaft lining. The local differential freezing pipe was successfully developed according to engineering requirements. Numeral simulations were used to predict the development of the freezing temperature field; the results showed that the inward expansion range of the frozen wall formed by the inner row freezing holes was effectively limited and the temperature drop rate of the shaft lining was significantly reduced after the local differential freezing technique was adopted. The on-site monitoring data showed that the temperature of the limited freezing layer was about 5°C higher than that of the conventional freezing layer. During the drainage work and the construction of the new shaft lining, the thickness and average temperature of the frozen wall remained stable, indicating that the implementation of the local differential freezing technology achieved the expected results. Further analysis showed that when the temperature of the limited freezing part of freezing pipes in the inner row was controlled within the range of −15 to −10°C, not only could the frozen wall reach the design thickness and strength but the frost heaving pressure on the existing shaft lining could be effectively eliminated.

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Numerical interpretation of temperature distributions from three ground freezing applications in urban tunnelling

Cited by 137 publications

References 2 publications

Study on the Formation Law of the Freezing Temperature Field of Freezing Shaft Sinking under the Action of Large-Flow-Rate Groundwater

Study on the Formation Law of the Freezing Temperature Field of Freezing Shaft Sinking under the Action of Large-Flow-Rate Groundwater

Experimental Study of the Mechanical Behavior of Frozen Soils - A Case Study of Tabriz Subway

Research and Application of the Local Differential Freezing Technology in Deep Alluvium

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