Artificial Ground Freezing to excavate a tunnel in sandy soil. Measurements and back analysis

Russo, Gianpiero; Corbo, Andrea; Cavuoto, F.; Autuori, Silvia

doi:10.1016/j.tust.2015.07.008

Cited by 116 publications

(35 citation statements)

References 8 publications

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“…Nowadays, this method is regularly used for construction works in urban areas. For example, it was applied during underground construction in New York [6], Nanjing [7], Napoli [8], Moscow [9] etc.…”

Section: Agf In Urban Constructionmentioning

confidence: 99%

Low-temperature ground freezing methods for underground construction in urban areas

Nikolaev

Shuplik

2019

MATEC Web Conf.

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Artificial ground freezing (AGF) is a commonly used ground improvement technique. It can be applied in diverse construction projects in dense populated urban areas where other methods are inapplicable. In this article are discussed several methods of ground freezing, such as: “brine” freezing, liquid nitrogen freezing, solid carbon dioxide freezing. Their advantages and disadvantages are indicated. For solid carbon dioxide freezing, several approaches are presented. One of them is a brine “aftercooling” freezing method. They can significantly increase efficiency of ground freezing and reduce its cost.

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Section: Agf In Urban Constructionmentioning

confidence: 99%

Low-temperature ground freezing methods for underground construction in urban areas

Nikolaev

Shuplik

2019

MATEC Web Conf.

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“…Figure 20 shows the outside view of the freezingcemented soil column, including the cement-mixed soil column and freezing pipe. e idea came from the artificial ground freezing method, which was adopted in this study to create a watertight connection between the tunnel and the shaft for conducting the tunnel boring [21,22]. e freezing pipe is made of seamless low-carbon steel or other pipes, such as PVC, PPR, ABS, and PE pipes.…”

Section: (4)mentioning

confidence: 99%

Engineering Characteristics and Reinforcement Approaches of Organic Sandy Soil

Jia

Wang

et al. 2018

Advances in Civil Engineering

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Organic sandy soil is widely distributed throughout Hainan Island. This study aimed at addressing the distribution, composition, and formation of organic sandy soil. The engineering properties of organic sandy soil were examined. The experimental results showed that the coefficient of uniformity and coefficient of curvature were 2.07 and 1.25, respectively. The maximum dry density and optimum water content were 1.723 g/cm3 and 12.23%, respectively. The undrained shear strength of organic sandy soil was around 37.5 kPa. The effective stress parameters c and φ were around 4 kPa and 23°, respectively. The compound tangent-exponential model was adopted for capturing the stress-strain behavior of organic sandy soil. As the unconfined compressive strength of the cement-admixed organic sandy soil was much lower than that of ordinary sand, some innovative ground improvement technologies were proposed for stabilizing organic sandy soil, such as thermal pile, fiber, and steel-, bamboo-, and freezing-cemented soil columns. The main purpose of these technologies is to enhance the bearing capacity of organic sandy soil but reduce the usage of cement, as the latter is not an eco-friendly material.

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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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Artificial Ground Freezing to excavate a tunnel in sandy soil. Measurements and back analysis

Cited by 116 publications

References 8 publications

Low-temperature ground freezing methods for underground construction in urban areas

Low-temperature ground freezing methods for underground construction in urban areas

Engineering Characteristics and Reinforcement Approaches of Organic Sandy Soil

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

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