西二线盾构穿越工程施工浆液的净化

Tunneling slurry purification of shield-driven tunneling engineering in the Second West-to-East Gas Pipeline

针对西气东输二线北江盾构穿越工程盾构机在粉质粘土层掘进过程中产生大量废弃浆液,导致盾构机泥水循环系统排渣效率降低、高速旋流装置能耗高和不利于环境保护等问题,研究了在盾构机泥水循环系统中加入泥浆无害化处理系统,解决高速旋流装置净化降效问题的方案(方案1:膨润土+CMC+纯碱+水,方案2:膨润土+粘土+CMC+纯碱+水),最终确定方案2适用于当地地层条件。现场应用及当地环保部门的测试评估结果表明:加入泥浆无害化压滤处理系统,能够提高盾构机泥水循环系统对粉质粘土的净化效率,经过净化的液体能够满足直接排放的环保要求,泥水循环系统较未进行泥水循环系统工艺流程改造前节能效果显著,具有良好的社会和经济效益。

According to the problem that the shield machine, used in the Beijiang shield-driven tunneling engineering of the second West-to-East Gas Pipeline, produced a great amount of waste slurry during the tunneling process in the silt-like clay layer, and thus caused a low slag discharge efficiency of slurry circulation system of the shield machine, high energy consumption of high-speed cyclone device, which was not conducive to environmental protection, etc., the authors studied to add a mud processing system to the slurry circulating system of the shield machine to solve the problem of decreased efficiency of high-speed cyclone device （Scheme 1： bentonite＋CMC＋soda ash＋water, Scheme 2： bentonite＋clay＋CMC＋soda ash＋water）, and finally confirmed that Scheme 2 was more suitable for local formation conditions. The field applications and testing and evaluation results of local environmental protection department showed that adding a mud filter press processing system can improve the purification efficiency of the shield machine＇s mud circulating system for silt-like clay, meeting the environmental requirements of direct discharge after the liquids treatment, and the slurry circulation system had an increased energy saving effect compared to the non-improved slurry circulating system, with sound social and economic benefits.