泥水盾构泥浆除砂的选择性絮凝剂应用研究

Application Research of Selective Flocculant Adopted in the Sand Removing from Shield Slurry

结合化学原理对盾构返排泥浆进行除砂是解决大量泥浆循环再用问题的一项重要技术,是促进盾构隧道工程高效、环保的积极措施。文章通过对部分水解聚丙烯酰胺(HPAM)分子结构特征的分析,揭示其电离基团与线性柔链可以选择性地捕捉、聚沉泥浆中的细微惰性岩屑,而保留泥浆中的造浆粘土。通过垂向容管压强测试等实验,验证了HPAM选择性絮凝的功效;并以分子量、水解度和添加浓度为3个主控因素对该类化学剂进行分析和遴选,为武汉地铁7号线过长江隧道盾构泥浆的使用提供了高效除砂的新方法。

It is an important technology for slurry recycling by sand removal in flowback slurry based on chemical principles and also an active measure to promote tunnelling efficiency and environmental protection.By analyzing the molecular structure characteristics of partially hydrolyzed polyacrylamide(HPAM),it reveals that the ionized group and linear soft chain can selectively capture and coagulate tiny inertia rock debris while the clay is still dis⁃persed in the slurry system.The effect of HPAM selective flocculation is verified by experiments like vertical tube pressure test.And analysis and selection are conducted to this kind of chemical agent by taking molecular weight,hy⁃drolysis degree and fortified concentration as the main controlling factors,providing a new method of sand removal for the slurry used in the Yangtze River-crossing shield tunnel of Wuhan metro line 7.