Tunnel ventilation during construction and diffusion of hazardous gases studied by numerical simulations

Chang, Xiaoke; Jaturapitakkul, Chai; Luo, Jia; Qin, Yuan; Xu, Zengguang; Cao, Jing

doi:10.1016/j.buildenv.2020.106902

Cited by 35 publications

(16 citation statements)

References 40 publications

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“…We can learn from the Niu et al 9 that the influence of the distance between the air duct outlet and the tunnel face on the ventilation field is studied. In the Chang et al, 10 the forced ventilation system used in tunnels was studied in terms of the position of the air duct and other factors. At the same time, according to the characteristics of the construction tunnel with the step method, the step size also changes with the different conditions of tunnel surrounding rock.…”

Section: Orthogonal Experimental Designmentioning

confidence: 99%

“…Niu et al 9 studied the influence of the distance between the air duct and the tunnel face and the diameter of the air duct on the flow field through numerical simulation for a specific project, and obtained the optimal combination which is suitable for the project. Chang et al 10 researched the ventilation and diffusion of harmful gases during tunnel construction under the influence of factors such as cross-sectional area and air velocity through numerical simulation, and obtained the function of pollutant distribution and construction ventilation time.…”

Section: Introductionmentioning

confidence: 99%

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Optimization principle and application of forced ventilation in railway tunnels based on improved TOPSIS theory and CFD simulations

Chen

Huang

2021

Advances in Mechanical Engineering

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The optimization of forced ventilation in tunnel construction becomes the key problem to improve the construction environment and energy saving. The influence of main factors on the flow field is considered for orthogonal experimental design and optimization, which includes the distance between the air duct outlet and the tunnel face, the bench length, the bench height, and the position of the air duct. Thus, the TOPSIS theory was adopted for the optimization method and improvement, and a series of CFD simulations were applied to analyze optimal solutions. The results show that the improved TOPSIS theory with entropy weight method and analytic hierarchy process could effectively solve the optimization problem of forced ventilation in tunnel construction. Based on this optimization principle, a case was analyzed, and the optimized ventilation parameters are obtained to improve ventilation efficiency and save energy. In the optimization scheme, the flow field in the tunnel is stable and the wind is strong enough to ventilate. Besides, there is none huge vortex, which might disrupt the stable flow field and reduce energy efficiency. It could improve the ventilation efficiency and stability, save time and cost, and bring considerable economic and social benefits to the tunnel construction.

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Section: Orthogonal Experimental Designmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Optimization principle and application of forced ventilation in railway tunnels based on improved TOPSIS theory and CFD simulations

Chen

Huang

2021

Advances in Mechanical Engineering

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“…Tunnel ventilation facilities are used to capture vehicle exhaust emissions within a tunnel and released it into the atmosphere using a "smoke stack" (Chang et al, 2020). Longer tunnels require ventilation stacks to regulate the air quality within the tunnel and ensure that it is suitable for human health and are often situated as close as possible to the tunnel portals, usually at the start and the end (Liu et al, 2020).…”

Section: Tunnel Ventilation Facilitiesmentioning

confidence: 99%

Are green wall technologies suitable for major transport infrastructure construction projects?

Iligan

Irga

2021

Urban Forestry & Urban Greening

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Many city's current transport infrastructure is deemed to be inadequate for rapid population growth and projected urbanisation, driving an increase in the construction of more efficient and reliable transport infrastructure and networks. However, transport infrastructure projects have negative impacts on the environment, during both the construction and operational phases.Green wall technologies have become an increasing trend within urban areas to combat these impacts, however, their uptake has been limited. This study answers the question of whether green wall technologies are a suitable technology for instilling sustainability into major infrastructure projects. This was achieved by comparing available green wall systems, conducting interviews with leading industry professionals and developing a case study on the possible areas of implementation of green wall technologies within a major multi-billion dollar infrastructure project. The overall benefits and constraints are presented, with insights into how these systems may contribute to sustainability rating tools for infrastructure projects.

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“…Other researchers have also studied the migration characteristics of toxic gases during the excavation of underground infrastructures in high-altitude areas [ 23 , 24 ] and concluded that the time required to dilute the toxic gas concentration decreases at lower altitudes. Chang et al [ 25 ] investigated the forced ventilation system during the construction of a roadway tunnel by applying CFD modeling. Different configurations of duct position, air velocity in the duct and distance from the mouth of the air duct to the tunnel face were examined to determine the CO concentration.…”

Section: Introductionmentioning

confidence: 99%

Concentration, Propagation and Dilution of Toxic Gases in Underground Excavations under Different Ventilation Modes

Menéndez¹,

Merlé

Oro

et al. 2022

IJERPH

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The drill-and-blast method is widely used for the excavation of hard rock tunnels. Toxic gases such as carbon monoxide and nitrogen oxides are released immediately after blasting by the detonation of explosives. To provide a safe working environment, the concentration of noxious gases must be reduced below the threshold limit value according to health and safety regulations. In this paper, one-dimensional mathematical models and three-dimensional CFD numerical simulations were conducted to analyze the concentration, propagation and dilution of the blasting fumes under different operating conditions. Forced, exhaust and mixed ventilation modes were compared to determine the safe re-entry times after blasting in a 200 m-long tunnel excavated using the top-heading-and-benching method. Based on the numerical simulations, carbon monoxide was the most critical gas, as it required a longer ventilation time to reduce its concentration below the threshold limit value. The safe re-entry time reached 480 s under the typical forced ventilation mode, but was reduced to 155 s when a mixed ventilation system was used after blasting, reducing the operating costs. The reduction of the re-entry time represents a significant improvement in the excavation cycle. In addition, the results obtained show that 1D models can be used to preliminary analyze the migration of toxic gases. However, to reliably determine the safe re-entry times, 3D numerical models should be developed. Finally, to verify the accuracy of the CFD results, field measurements were carried out in a railway tunnel using gas sensors. In general, good agreements were obtained between the 3D numerical simulations and the measured values.

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Tunnel ventilation during construction and diffusion of hazardous gases studied by numerical simulations

Cited by 35 publications

References 40 publications

Optimization principle and application of forced ventilation in railway tunnels based on improved TOPSIS theory and CFD simulations

Optimization principle and application of forced ventilation in railway tunnels based on improved TOPSIS theory and CFD simulations

Are green wall technologies suitable for major transport infrastructure construction projects?

Concentration, Propagation and Dilution of Toxic Gases in Underground Excavations under Different Ventilation Modes

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