Analysis of calculation of fresh-air demand for road tunnel ventilation design in China

Wang, Xu; Wang, Mingnian; Cai, Jia; Yan, Tao; Bao, Yifan; Chen, Jinyu; Qin, Pengcheng; Li, Kunjie; Deng, Tao; Yan, Guanfeng

doi:10.1016/j.tust.2020.103469

Cited by 16 publications

(3 citation statements)

References 42 publications

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“…Theoretical solutions 41 are expressed as Eqs. ( 5 ), ( 6 ), ( 7 ) and ( 8 ), where , and are the radial stress, tangential stress and shear stress at any point in the surrounding rock respectively, and the shear stress is positive when the normal outside the plane of action is consistent with the coordinate axis and the stress direction is opposite to the coordinate axis; is equivalent to SPC; r and is the polar coordinate of any point in the surrounding rock; is the initial ground stress; r 0 is the tunnel radius.…”

Section: Stability Differences Of Rock Pillar Between Left–right Tunn...mentioning

confidence: 99%

Stability evaluation of rock pillar between twin tunnels using the YAI

Zhang

Liu

et al. 2023

Sci Rep

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The stability of rock pillar is crucial for ensuring the construction safety of twin tunnels with small clearance, especially when transitioning from the traditional left–right tunnel layouts to the up-down configurations due to complex and variable site constraints. However, there are limited researches on the evaluation and comparative study of the stability of these two types of rock pillars in twin tunnels. This paper introduces the yield approach index (YAI) as a measure to assess the stability of rock pillar in twin tunnels with small clearance, and various influencing factors including side pressure coefficient (SPC), stress release rate (SRR), and the thickness of rock pillar (characterised by the ratio of rock pillar thickness to tunnel diameter, RPT/TD) are considered in the analysis. The study compares and analyzes the stability differences of the rock pillar in different situations. It is observed that the two sides of up-down tunnels pose a higher risk while the rock pillar in the left–right configuration being the most vulnerable. The stability of the rock pillar between the up-down tunnels is significantly higher than that of the left–right tunnels under similar conditions. Moreover, the up-down tunnels exhibit greater sensitivity to SPC, whereas the left–right tunnels are more sensitive to SRR. Additionally, the study reveals that increasing the RPT/TD can effectively improve the stability of the rock pillar within a specific range (1/4 to 2/3). The research method and obtained results of this paper can provide some important references for the stability evaluation and design of twin tunnels with small clearance.

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Section: Stability Differences Of Rock Pillar Between Left–right Tunn...mentioning

confidence: 99%

Stability evaluation of rock pillar between twin tunnels using the YAI

Zhang

Liu

et al. 2023

Sci Rep

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“…Utility tunnels address the issue of repetitive road surface excavation caused by pipeline maintenance and effectively utilize the urban underground space [2,3]. The first utility tunnel in China was built under Tiananmen Square in 1959, stretching 1076 m, and transported district heating, electric power, water, and other utilities to Beijing citizens [4]. Since then, the construction of utility tunnels in China has experienced significant growth, resulting in utility tunnels spanning nearly 6000 km being built between 2015 and 2022 [5].…”

Section: Introductionmentioning

confidence: 99%

Pseudo-Static Tests on Top Joints of Hybrid Precast Utility Tunnel

Xue,

Chen,

Bai

2023

Buildings

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This paper introduces a new type of hybrid precast MUT, consisting of precast composite top slab and double-skin sidewalls with reserved rebar. The seismic behavior of the top joints was examined through pseudo-static tests. Four full-scale specimens, including both exterior and interior precast joints, in addition to two corresponding cast-in-place (CIP) joints, were fabricated and subjected to reversed cyclic loading. The results showed that both the precast and CIP joints exhibited flexure failure, characterized by the formation of a plastic hinge at the end of the sidewall. The hysteresis curves of both precast and CIP joints exhibited comparable shapes and quantities of hysteresis loops. The load-carrying capacities for exterior precast joints and corresponding CIP joints were 141.25 kN and 143.5 kN, exhibiting a difference of less than 1.6%. The load-carrying capacities for interior precast and corresponding CIP joints were 60.5 kN and 62.75 kN, displaying a variance of less than 3.6%. The precast specimens demonstrated comparable levels of ductility, energy dissipation, and structural integrity as the CIP specimens. These findings provide validation for designing and analyzing the hybrid precast utility tunnel using identical principles and models as applied CIP structures.

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“…They have pointed out that both ventilation velocity and time are crucial parameters that determine the air temperatures in the tunnel and surrounding rocks. Wang et al [31] have investigated domestic and foreign tunnel ventilation design standards and have analyzed the impact of emission generation formula, base emission rates, and time factors on ventilation system design through a calculation example. Their research shows that the 2017 Shanghai Code and 2019 PIARC Ventilation Report consider the impact of NO2 and non-emission particles on the demand for fresh air in tunnels, whereas the 2014 China Guidelines do not.…”

Section: Introductionmentioning

confidence: 99%

Study on Temperature Distribution along the Ultra-Long Underwater Tunnel: Based on the Long-Term Measured Results of the Shanghai Yangtze River Tunnel

Gao

Guo

et al. 2023

Buildings

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Tunnels play a vital role in enhancing traffic flow and supporting public transportation systems. However, the discharge of polluted air and waste heat from vehicles passing through tunnels significantly raises the temperature inside, presenting challenges in terms of occupant comfort, tunnel safety, and infrastructure integrity. Therefore, ensuring proper temperature control is essential for their efficient operation. This study aims to investigate the phenomenon of temperature rise in ultra-long tunnels during normal operations, as limited research has been conducted in this area. The Shanghai Yangtze River Tunnel serves as a case study, utilizing temperature and air velocity data collected throughout the year (2021) from the management company. The analysis reveals that the temperature distribution near the tunnel exit is influenced by outdoor temperature fluctuations and traffic volume. The highest temperatures occur on 25 August (39.74 °C) during peak traffic hours. On-site measurements of tunnel temperature, humidity, and air velocity during winter and summer seasons yield the following results. During winter, the air temperature and wall temperature inside the tunnel experience significant increases along its length. The air temperature rises by approximately 11 °C from the entrance to the exit, while the wall temperature increases by about 15 °C. In contrast, during summer, the air temperature only rises by 2.7 °C, and the wall temperature increases by around 3 °C. Consequently, the humidity decreases along the tunnel, and this decrease is correlated with the magnitude of temperature increase. Furthermore, measurements of air velocity indicate that natural and traffic-induced winds contribute to the overall airflow inside the tunnel. A temperature data logger installed in the tunnel recorded temperature changes during the period of pandemic lockdown and subsequent recovery, spanning the spring and summer seasons. During the lockdown period, there was a relatively small increase in temperature along the tunnel, suggesting that vehicle heat dissipation is the primary factor contributing to temperature rise inside. Additionally, a method is proposed to predict the cross-sectional temperature of the tunnel using measured air velocities.

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Analysis of calculation of fresh-air demand for road tunnel ventilation design in China

Cited by 16 publications

References 42 publications

Stability evaluation of rock pillar between twin tunnels using the YAI

Stability evaluation of rock pillar between twin tunnels using the YAI

Pseudo-Static Tests on Top Joints of Hybrid Precast Utility Tunnel

Study on Temperature Distribution along the Ultra-Long Underwater Tunnel: Based on the Long-Term Measured Results of the Shanghai Yangtze River Tunnel

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