敞开式TBM施工隧道粉尘扩散及除尘系统研究

TBM掘进过程中产生大量粉尘,为了掌握粉尘的分布规律并优化除尘系统,以敞开式TBM为例,采用数值计算方法研究不同除尘风管位置,不同除尘风速和不同掘进面产尘量下的洞内粉尘浓度分布规律。研究结果表明:敞开式TBM隧道施工过程中,掘进面至除尘风管区域质量粉尘浓度较高,在除尘风管口后方区域下降到 2 mg/m^3 以下;除尘风管布置在距掘进面30 m位置处时,洞内沿程粉尘含量相对较大,除尘风管布置在距掘进面20 m位置处时洞内沿程及TBM支护区域粉尘含量相对较小;排风风速为15 m/s时,敞开式TBM支护区域粉尘质量浓度最小,排风风速为30 m/s时,该区域粉尘质量浓度最大;掘进面产尘量越大,洞内沿程及敞开式TBM支护区域粉尘质量浓度越大,不同产尘量下洞内粉尘浓度均在除尘风管后方达到规范限值以下。

Study on dust diffusion and dust removal system of open type TBM construction tunnel

A large amount of dust is generated during the TBM excavation process. In order to grasp the distribution laws of dust and optimize the dust removal system, taking the open type TBM as an example, the distribution laws of dust concentration in the cavern under different positions of dust removing air duct, different wind speeds of dust removal and different dust generation amounts at the heading face were studied by using the numerical calculation method. The results showed that during the construction process of open type TBM tunnel, the mass concentration of dust in the area from the heading face to the dust removing air duct was higher, and it reduced to below 2 mg/m3 in the area behind the inlet of dust removing air duct. When the dust removing air duct was arranged at the position of 30 m away from the heading face, the dust content along the tunnel was relatively large. When the dust removing air duct was arranged at the position of 20 m away from the heading face, the dust contents along the tunnel and in the TBM supporting area were relatively small. When the dust removal wind speed was 15 m/s, the mass concentration of dust in the open type TBM supporting area was the smallest, and the mass concentration of dust in this area was the largest when the dust removal wind speed was 30 m/s. The greater the amount of dust generated at the heading face, the greater the mass concentration of dust along the tunnel and in the open type TBM support area. The dust concentrations in the cavern under different amounts of dust generation were all below the specification limit behind the dust removing air duct.