铁路隧道钻爆法施工废水治理关键技术研究

为进一步提高隧道施工废水处理技术水平,围绕其水质、设计水量以及处理工艺等关键技术开展了研究。对西南、华南及西北地区典型铁路隧道开展了广泛调研和水质检测,结果显示:施工废水中悬浮物是主要污染物,且pH值>7呈碱性,COD、石油类则为非主要污染物。据此将废水处理工艺优化为沉砂、调节pH、混凝、沉淀、过滤,不再保留气浮处理流程,经现场试验验证,经该工艺处理后的隧道施工废水出水水质能够符合《污水综合排放标准》(GB8978—1996)规定的一级排放标准。明确了隧道施工废水由施工作业废水和隧道施工涌水组成、且以后者为主的观点,较为系统地阐述了隧道衬砌、注浆等对涌水量的影响,推荐以水文地质预测正常涌水量为基准,并根据隧道防排水设计、隧道正洞施工分段划分、辅助坑道设置和工期等条件,提出隧道施工废水水量计算方法。

Study on Key Technology of Sewage Treatment for Railway Tunneling by Drilling and Blasting

In order to improve the technological level of railway tunnel construction waste water treatment projects in China, investigations and surveys are conducted focusing on water quality, quantity and treatment processes throughout Southwest, Northwest, South and North China. The results show that SS and pH are the two main pollutant factors, while COD, HN~(4+)-N, TP and petroleum are not. According to the survey, an optimization technical"grit removal+pH adjusting+coagulation+precipitation+filtration" is proposed, and the"air flotation" process is canceled. As verified by the engineering practices, the effluents after the treatment meet the demand of first level specified in Integrated Wastewater Discharge Standard(GB8978-1996). It is believed that the tunnel construction sewage consists of operation waste water and polluted gushing groundwater, and the latter is the main source of construction sewage. In this article, a detailed and systematic analysis is presented of the influence of tunnel lining and grouting on the water inflow. Taking into consideration of the effects of construction measures like drainage hole, tunnel lining and grouting, segmentation, auxiliary tunnel setting and the construction period, a calculation method of tunnel construction sewage is put forward.