工地扬尘管控措施效果量化研究

Quantitative effect evaluation on dust control measures of construction sites

  • 摘要: 随着城市规划建设,大规模建筑工程在地基开挖、主体建设、外墙装修过程中,会产生以粗颗粒物(PM10)为代表的众多大气污染物。为尽量减少建筑工地扬尘产生PM10,相关部门要求建筑工地采取裸土覆盖、立体喷淋、围挡隔离等抑尘措施。基于现场抑尘措施控制试验和高精度数值风洞试验对各措施的抑尘效果进行逐一探究。结果表明:只开围挡喷淋时PM10浓度下降5.1%,只开施工喷淋时浓度下降12.3%,二者全开时浓度下降11.4%。风速较大时,裸土覆盖的抑尘效果比小风天气显著,在三级风(大于2 m/s)下裸土覆盖的PM10浓度均值相比裸土不覆盖时平均下降10.7%。裸土喷淋后的PM10浓度比不喷淋时下降21.3%。整体上基坑阶段在围挡2、3、4和5 m时的扬尘削减率分别为3.6%、10.5%、18.4%和29.0%。在主体阶段,随着排放源的升高,扬尘扩散的影响距离逐渐降低。当源高10 m时,最大影响距离为工地外75 m;当源高30 m时,最大影响距离为工地外50 m;当源高50和90 m时,刚出工地的扬尘逸散率便在10%以内,即对工地外的影响可以忽略。

     

    Abstract: With the urban planning and construction, large-scale construction projects have produced amounts of atmospheric pollutants represented by coarse particulate matter (PM10) in the process of foundation excavation, main construction and exterior wall decoration. In order to minimize PM10 caused by dust at construction sites, relevant departments require to take dust suppression measures at construction sites such as bare soil covering, stereoscopic spraying and enclosure isolation. The dust suppression effect of each measure was explored based on the on-site dust suppression measure controlled experiments and high-precision numerical wind tunnel experiments. The results showed that PM10 concentration decreased by 5.1% when only using enclosure spraying, the concentration decreased by 12.3% when only using construction spraying, and when both measures were used, the concentration decreased by 11.4%. When the wind speed was high, the dust suppression effect of bare soil cover was more significant than that of low wind, and the mean PM10 concentration of bare soil cover under third-level wind (>2 m/s) was 10.7% lower than that without bare soil cover. PM10 concentration of bare soil spray decreased by 21.3% compared with that of no spray. On the whole, the dust reduction rates during the foundation excavation stage were 3.6%, 10.5%, 18.4% and 29.0% for enclosure heights of 2, 3, 4 and 5 m, respectively. In the main construction stage, the influence distance of dust diffusion gradually decreased with the increase of emission source. When the source height was 10 m, the maximum influence distance was 75 m outside the construction site; when the source height was 30m, the maximum influence distance was 50 m. When the source height was 50 and 90 m, the dust dissipation rate was less than 10% as soon as the dust source left the site, which means that the impact outside the site could be ignored.

     

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