为更快速有效地清除隧道钻爆施工所产生的粉尘,提出“辅助降尘注水孔方案”、“差异水袋布置方案”、“降尘注水孔+差异水袋布置” 3种新的水封爆破除尘技术方案。依托轿顶隧道进行现场试验,得到初始状态下掌子面区域纵、横向特征位置的粉尘质量浓度,CO、CO2、O2、NO2体积分数分布情况,通风条件下纵向特征位置的粉尘质量浓度、CO体积分数随时间的变化规律,3种新型水封爆破方案下掌子面区域纵、横向特征测试位置的粉尘质量浓度、CO体积分数分布规律。经研究得出如下结论: 1)通风10 min内是粉尘质量浓度、CO体积分数下降最快的阶段; 2)新型水封爆破除尘方案的降尘效果明显,3种方案最大降尘比例依次为36.84%、40.85%、65.74%; 3)降尘注水孔对爆破粉尘可起到良好的“封闭”作用; 4)新型水封爆破方案可起到明显降低CO体积分数的作用。
In order to
remove the dust produced by the tunnel drilling and blasting construction more
quickly and effectively, three new dust removal technical schemes, i.e.
auxiliary dust reduction water injection hole, differential water bag
arrangement, and dust reduction water injection hole + differential water bag
arrangement, are proposed, and field test is carried out on Jiaoding Tunnel.
The test results obtained are as follows: the concentration distribution of
dust, CO, CO2, O2 and NO2 in
the longitudinal and transverse characteristic positions of the tunnel face
area in the initial state, the variation rules of dust and CO concentration in
the longitudinal characteristic positions with time under ventilation
conditions, and the concentration distribution of dust and CO in the
longitudinal and transverse characteristic test positions of the tunnel face
area under three new hydraulic blasting schemes. Some conclusions are drawn as
follows: (1) The concentration of dust and CO decreases fastest within 10
minutes of ventilation. (2) The dust reduction effect of the new scheme of
hydraulic blasting is obvious, and the maximum dust reduction ratios of the
three schemes are 36.84%,
40.85% and 65.74%, respectively. (3) The dust reduction water injection hole
can play a good role in "sealing" the blasting dust. (4) The new
scheme of hydraulic blasting can significantly reduce the CO concentration.