Parametric modeling study for blown-dust secondary pollution and optimal ventilation velocity during tunnel construction
Parametric modeling study for blown-dust secondary pollution and optimal ventilation velocity during tunnel construction
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DOI：
10.1016/j.envpol.2023.122239
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发表时间：
2023-08-02
影响因子：
8.9
通讯作者：
Hu, Jing
中科院分区：
文献类型：
--
作者：
Guo, Jinnan;Li, Angui;Hu, Jing
隧道施工通常依赖于钻孔和爆破。粉尘污染严重是钻爆施工的主要问题之一。通风引起的二次扬尘污染水平与钻井施工引起的扬尘污染水平相当。通过受力分析，建立了沉积粉尘的临界流动模型和扬尘率模型，并与试验数据进行了验证。研究结果表明，当隧道直径为10 m时，对直径为100 μ m的粉尘颗粒的特征风速可达0.42 m/s左右，通风Re值在光滑和粗糙条件下分别为2.3 × 105和1.4 × 105。此外，当通风Re达到4 × 105时，在平稳条件下通风引起的扬尘污染率约为1.8 × 10-2 kg/s。当粉尘粒径大于或小于临界粉尘粒径时，特征气流速度增大。此外，在隧道施工过程中，沉积的灰尘不流动或移动的最佳速度与隧道的尺寸和粗糙度有关。对于直径为10 m的光滑隧道，最佳通风速度为3.5 m/s。当隧道粗糙度从0.005增加到0.5 m时，最佳通风速度从3.3 m/s降低到1.6 m/s。研究建立的积尘临界流模型和扬尘污染率模型为隧道通风最佳风速的选择和通风二次扬尘污染风险的识别提供了理论依据。
Tunnel construction often relies on drilling and blasting. High dust pollution is one of the primary problems of drilling and blasting construction. The level of secondary blown dust pollution caused by ventilation matches that of dust pollution caused by drilling construction. In this study, a critical flow model and blown dust rate model for deposited dust were established via force analysis, which was validated against the test data. The research results showed that the characteristic airflow velocity for blowing dust particles with a 100 & mu;m diameter reached approximately 0.42 m/s for tunnel diameter is 10 m, and the ventilation Re values under smooth and rough conditions were 2.3 x 105 and 1.4 x 105, respectively. Furthermore, when ventilation Re reached 4 x 105, the blown dust pollution rate caused by ventilation under smooth conditions was approximately 1.8 x 10-2 kg/s. If dust particle size is more or less the critical dust particle size, the characteristic airflow velocity was increased. Moreover, the optimal velocity at which the deposited dust does not flow or move during tunnel construction was related to the tunnel size and roughness. For the smooth tunnel with a diameter of 10 m, the optimal ventilation velocity was 3.5 m/s. When the tunnel roughness was increased from 0.005 to 0.5 m, the optimal ventilation velocity decreased from 3.3 to 1.6 m/s. The deposited dust critical flow model and blown dust pollution rate model established in this study provide a sound theoretical basis for selecting the optimal velocity of tunnel ventilation and recognizing the risks of secondary blown dust pollution due to ventilation.