Evolution Law of Three-Dimensional Non-Uniform Temperature Field of Tunnel Construction Using Local Horizontal Freezing Technique

Pang, Changqiang; Cai, Haibing; Hong, Rongbao; Li, Mengkai; Yang, Zhe

doi:10.3390/app12168093

Cited by 3 publications

(1 citation statement)

References 17 publications

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“…The artificial ground freezing method is applicable to the construction of underground work in water rich areas. This construction method has been widely used in the construction of new coal mine shafts [6,7] and damaged shafts [8], the construction of highway tunnels in coastal cities [9,10], the reinforcement of urban subway tunnel shield tunnel entrances and exits [11], the construction of subway tunnel connecting passages [12][13][14], foundation pit works [15], underground restricted natural gas storage tanks [16], etc.…”

Section: Introductionmentioning

confidence: 99%

Mechanical Analysis of Frozen Wall with Trapezoidal Temperature Field Distribution Based on Unified Strength Theory

Shi

Long

et al. 2022

Applied Sciences

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In order to study the elastic–plastic stress field distribution of a double-row-pipe frozen wall, the temperature field of the double-row-pipe frozen wall is equivalent to a trapezoidal distribution, and the frozen wall is regarded as an elastic–plastic thick-walled cylinder with functionally gradient material (FGM) characteristics in the radial direction. Considering that the elastic modulus and cohesion of the frozen wall material change linearly with the radius, the elastic–plastic analysis of the frozen wall is carried out based on unified strength theory. The analytical solutions of the elastic–plastic stress field distribution, the elastic ultimate bearing capacity, the plastic ultimate bearing capacity, and the relative radius of the plastic zone of the frozen wall are derived. The analytical solution is calculated based on the engineering case and compared with the numerical solution obtained based on COMSOL. At the same time, the influence of strength theory parameters on the mechanical properties of heterogeneous and homogeneous frozen walls is analyzed. The results show that the analytical solution and the numerical solution are in good agreement, and their accuracy is mutually verified. The external load on the frozen wall of the selected layer is greater than its elastic ultimate bearing capacity and less than its plastic ultimate bearing capacity, which indicates that the frozen wall is in a safe state of stress. The radial stress increases with the increase in the strength theoretical parameter b and the relative radius r, the tangential stress increases with the increase in the strength theoretical parameter b, and first increases and then decreases with the increase in the relative radius r. The larger the strength theoretical parameter b, the smaller the relative radius of the plastic zone of the frozen wall. The strength theoretical parameter b increases from 0 to 1, the elastic ultimate bearing capacity and plastic ultimate bearing capacity of the heterogeneous frozen wall increase by 33.3% and 40.8%, respectively, and the elastic ultimate bearing capacity and plastic ultimate bearing capacity of the homogeneous frozen wall increase by 33.3% and 41.0%, respectively. Therefore, considering the influence of intermediate principal stress, the potential of materials can be fully exerted and the ultimate bearing capacity of frozen walls can be improved. This study can provide theoretical reference for the design and construction of frozen wall.

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Section: Introductionmentioning

confidence: 99%

Mechanical Analysis of Frozen Wall with Trapezoidal Temperature Field Distribution Based on Unified Strength Theory

Shi

Long

et al. 2022

Applied Sciences

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Research on Frost Heaving Distribution of Seepage Stratum in Tunnel Construction Using Horizontal Freezing Technique

Cai

Liu

et al. 2022

Applied Sciences

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During the horizontal freezing construction of a subway tunnel, the delay of the closure of the frozen wall occurs frequently due to the existence of groundwater seepage, which can be directly reflected by a freezing temperature field. Accordingly, the distribution of ground surface frost heaving displacement under seepage conditions will be different from that under hydrostatic conditions. In view of this, this paper uses COMSOL to realize the hydro–thermal coupling in frozen stratum under seepage conditions, then, the frost heaving distribution of seepage stratum in tunnel construction using horizontal freezing technique is researched considering the ice–water phase transition and orthotropic deformation characteristics of frozen–thawed soil by ABAQUS. The results show that the expansion speed of upstream frozen wall is obviously slower than that of the downstream frozen wall, and the freezing temperature field is symmetrical along the seepage direction. In addition, the ground frost heaving displacement field is asymmetrically distributed along the tunnel center line, which is manifested in that the vertical frost heaving displacement of the upstream stratum is less than that of the downstream stratum. The vertical frost heaving displacement of the ground surface decreases with the increase in tunnel buried depth, but the position of the maximum value remains unchanged as the tunnel buried depth increases. The numerical simulation method established in this paper can provide a theoretical basis and design reference for the construction of a subway tunnel in a water-rich stratum under different seepage using the artificial freezing technique.

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Temporal and Spatial Evolution Law of the Freezing Temperature Field of Water-Rich Sandy Soil under Groundwater Seepage: A Case Study

et al. 2022

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We aimed to assess the temporal and spatial evolution law of the freezing temperature field of water-rich sandy soil in underground freezing engineering, taking the newly built west ventilating shaft freezing engineering in the Yuandian No. 2 Mine of Huaibei Coalfield as the engineering background. The influence of groundwater seepage on the freezing temperature field was qualitatively analyzed using field measured data. Based on the mixture medium theory, a hydrothermal coupling numerical calculation model of the freezing temperature field was established. The temporal and spatial evolution law of the freezing temperature field of water-rich sandy soil was obtained via the analysis of field measured data and numerical calculation results. It was found that the proportion of water that froze into ice in the soil mass within the freezing pipe circle is more than that outside of the freezing pipe circle; thus, the phase change in the soil mass within the freezing pipe circle is highly obvious. Groundwater seepage has an “erosion” effect on the upstream and side frozen walls and a “cooling superposition” effect on the downstream frozen wall. Under the effect of groundwater seepage of 2.81 m/d, the average temperature of the effective frozen wall during excavation is below −15 °C, while the thickness is above 5 m for the selected sandy layer at the site, meeting the construction and design requirements. When the groundwater flow rate increases from 0 to 10 m/d, the closure time of the frozen wall increases from 27 to 49 days, an 81.48% increase; the upstream thickness of the effective frozen wall decreases from 5.635 to 4.65 m, which represents a 17.48% decrease, while the downstream thickness increases from 5.664 to 7.393 m, an increase of 30.60%. The numerical calculation model in this paper can be used to predict the development law of the freezing temperature field of the water-rich sandy layers in the Yuandian No. 2 mine and to adjust the on-site cooling plan in real time according to the construction progress. This study provides some theoretical basis and reference for the construction and designs of the freezing temperature fields of water-rich sandy soil layers.

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Evolution Law of Three-Dimensional Non-Uniform Temperature Field of Tunnel Construction Using Local Horizontal Freezing Technique

Cited by 3 publications

References 17 publications

Mechanical Analysis of Frozen Wall with Trapezoidal Temperature Field Distribution Based on Unified Strength Theory

Mechanical Analysis of Frozen Wall with Trapezoidal Temperature Field Distribution Based on Unified Strength Theory

Research on Frost Heaving Distribution of Seepage Stratum in Tunnel Construction Using Horizontal Freezing Technique

Temporal and Spatial Evolution Law of the Freezing Temperature Field of Water-Rich Sandy Soil under Groundwater Seepage: A Case Study

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