Elsevier

Transportation Geotechnics

Volume 30, September 2021, 100615
Transportation Geotechnics

Thermal characteristics investigation of a high-speed railway tunnel by field monitoring in Northeast of China

https://doi.org/10.1016/j.trgeo.2021.100615Get rights and content

Highlights

  • The change laws of temperature inside tunnel are discussed.

  • The influence factors of thermal characteristics inside the tunnel are analyzed.

  • The frost depth and frost index in different sections are revealed.

Abstract

Thermal characteristics of tunnel in cold regions determine whether it will be affected by frost damage. Within this context, a series of key environmental factors were recorded by filed monitoring, such as temperature, wind speed and wind direction at tunnel site. The results demonstrate that environmental factors, topography and tunnel orientation codetermine the thermal characteristics inside the tunnel. In the coldest day, the temperature of air and tunnel structure distributed in the asymmetric parabola curve except surrounding rock. Meanwhile, the temperature of surrounding rock is always positive in the whole monitoring period, which varied slightly with season. The wind speed inside the tunnel is directly affected by that outside the tunnel, especially at ends of tunnel. With the distance increasing from tunnel entrance to the exit, the frost depth and frost index first decreased and then increased. Additionally, the temperature of all monitoring points in the same section increased with the distance from the sidewall to surrounding rock. This study can provide some information about the thermal characteristics and references for design and maintenance of the cold-regional tunnels.

Graphical abstract

Comprehensive environmental factors at tunnel site, including air temperature, ground temperature, wind speed and wind direction, were monitored from 2018 to 2020. The effects of these factors and topography on thermal characteristics inside the tunnel were analyzed and discussed in details, especially in freezing period.

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Introduction

The cold regions is defined as the area that the annual mean air temperature is under 5 ℃ [1]. It accounts for 55% of the earth land area and mainly distributes in the United States, Canada, Russia, Japan as well as China [2]. Inevitably, cold regional tunnels are suffered from the threats induced by cold environment, and the frost damage of tunnels is observed in many countries, such as China, Germany, France, Russia, Norway, Japan and Italy [3], [4], [5], [6]. In China, cold regions mainly distribute in the Qinghai-Tibet Plateau and the Northeast area, which accounts for approximately 43.5% of land total territory [7], as shown in Fig. 1. And also, various types of frost damage occur in these areas, including icing on sidewall and vault, rail freezing, concrete peeling off and cracking [8], [9], [10]. As a result, the frost damage seriously interferes with the transportation and increases the maintenance costs of tunnels [11], [12]. Some of tunnels in China cannot be used for about 9 months in a year due to the frost damage [13].

Fig. 1. Annual mean air temperature and frost damage of the cold-regional tunnels (The data was downloaded from the China Meteorological Data Service Center (CMDC) (http://data.cma.cn/en)) (Unit: ℃): (a) Annual mean air temperature and railway net in China; (b) Dangjin Mountain tunnel [14]; (c) Kunlun Mountain tunnel [15]; (d) Lingding tunnel [16]; (e) Shuangmiaozi tunnel.

Low temperature [17], ground water [18] and frost heave force [19] are three extremely important inducements for the frost damage. The temperature decreases beneath 0 ℃ and the water freezes into ice in winter, resulting in that the lining and rock mass are increased in volume accompanied by the frost heave and water migration [20]. Subsequently, different forms of frost damage appears inside the tunnel. Therefore, in order to estimate the position and level of frost damage of tunnels, the investigation on the thermal characteristics is necessary.

Until now, some scholars have focused on the air temperature in the longitudinal direction of tunnel, and two common characteristics of temperature distribution are recognized. One of the characteristics is that the air temperature distribution is non-uniform and changes with season. Another is that the temperature at the tunnel port is lower than that at tunnel center in winter, but it is opposite in summer [21]. The amplitude variation of air temperature also decreases gradually with the increasing of the distance from tunnel entrance to exit [22]. But, it is not enough to effectively mitigate the frost damage by analyzing the temperature in the longitudinal direction of tunnel [23]. Meanwhile, some scholars have focused on the temperature distribution in the radial direction. The temperature increases gradually from vault to mountain surface and decreases from secondary lining surface to center for the permafrost tunnel [24]. Besides, the temperature of air is highest, then followed by that at shoulder and pavement [25]. Based on these researches, some anti-frost measures were proposed, such as layering insulation board, installing electric tracing and cold proof door. However, the frost damage is still occurring in some tunnels, especially for high-speed rail tunnel.

On the other hand, the abovementioned researches have focused on the tunnels that servicing for regular railways and have not considered the influence of environmental factors outside the tunnel. Until now, there is a lack of systematic research about thermal characteristics of cold-regional tunnels that servicing for the high speed railways by field monitoring with high frequency and long-terms.

In this study, the development process of the temperature in longitudinal and in radial direction of the tunnel that servicing for high-speed rail are analyzed based on the filed monitoring from 2018 to 2020. The relationship of environmental factors between outside and inside the tunnel is disclosed, especially in the cold season. The frost depth and frost index in different sections are discussed. This study can provide some information for the change process of air temperature inside the tunnel and the temperature of tunnel structure in cold regions, and also can provide reference for anti-frost design and construction of tunnels.

Section snippets

Basic information of project and tunnel site

The Jilin-Tumen-Hunchun Passenger Dedicated Line (JTHPDL) was opened for servicing in 2015, which connects the Jilin city and Hunchun city, with the total length of 361 km. The whole route is seasonally frozen ground and the frost depth ranges from 1.70 m to 1.80 m [26], as shown in Fig. 2(a). The studied tunnel (Gaotai tunnel) is located in Antu county (128.55 E, 43.07 N) with the length of 3706 m. The cross section of the studied tunnel is shown in Fig. 2(b).The width and the height of the

Air temperature and natural wind

The thermal characteristics inside the tunnel are highly influenced by environmental factors at tunnel site [29]. In this study, the change characteristics of air temperature and wind speed, wind direction and ground temperature outside the tunnel are analyzed and discussed.

From Fig. 7, it can be seen that the monthly mean air temperature varied in the sine curve, both at tunnel entrance and exit. The maximum temperature was about 11 °C and occurred in July. Meanwhile, the minimum temperature

Conclusions

In this study, the key environmental factors and temperature distribution inside and outside the tunnel were monitored. Subsequently, on the basis of the monitored results and analyses presented herein, the following conclusions can be drawn:

  • (1)

    The ground temperature at tunnel site is mainly influenced by air temperature, wind speed, elevation and topography. The temperature distribution inside the tunnel is mainly influenced by air temperature, wind speed, wind direction, topography and tunnel

CRediT authorship contribution statement

Haiqiang Jiang: Formal analysis, Methodology, Writing - review & editing. Fujun Niu: Resources, Funding acquisition, Supervision, Writing - review & editing. Qinguo Ma: Resources. Wangtao Jiang: Writing - review & editing. He Hu: Writing - review & editing. Enliang Wang: Writing - review & editing. Chenglong Jiao: Writing - review & editing. Zhiguo Li: Resources.

Declaration of Competing Interest

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Acknowledgements

This study was financially supported by the Strategic Priority Research Program of the Chinese Academy of Sciences (Grant No.XDA19070504), Natural Science Foundation of Guangdong Province (Grant No. 2020A1515010745). The authors would like to thank the anonymous reviewers of this paper for their constructive comments.

References (31)

  • R. Xing et al.

    Long-term temperature monitoring of tunnel in high-cold and high-altitude area using distributed temperature monitoring system

    Measurement

    (2016)
  • S. Inokuma

    Inano. Road tunnels in Japan: deterioration and countermeasures

    Tunn Undergr Space Technol

    (1996)
  • X. Wang et al.

    Analysis of freeze-thaw characteristics of Kunlun mountains tunnel

    Rock Soil Mech

    (2006)
  • J. Feng et al.

    Study of defect distribution regularity in existing tunnels and the classification of tunnel environments

    Mod Tunnel Technol

    (2013)
  • R. Chen et al.

    Cold regions in China

    J Glaciol Geocryol

    (2005)
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