盾构隧道废弃泥浆絮凝沉淀试验及处理效果评价

Flocculation and Sedimentation Test of Abandoned Slurry in Shield Tunnel and Evaluation of Treatment Effect

为明确盾构隧道废弃泥浆的固液分离性能,提高分离效率,试验选取非离子型聚丙烯酰胺、阴离子型聚丙烯酰胺以及聚合氯化铝作为研究对象,研究三者在不同分子量、浓度及添加量下的絮凝沉淀效果。基于单一絮凝剂的试验结果,进一步选取复合絮凝剂进行试验研究。结果表明,絮凝效果由强到弱的排序为阴离子型聚丙烯酰胺>非离子型聚丙烯酰胺>聚合氯化铝,其中阴离子型聚丙烯酰胺的絮凝沉淀效果远远好于非离子型聚丙烯酰胺及聚合氯化铝,有机絮凝剂聚合氯化铝的泥水分离速度比其他两种絮凝剂慢,但上清液浊度远远低于无机高分子絮凝剂。对比分析发现,复合絮凝剂阴离子型聚丙烯酰胺添加量为70 mL,聚合氯化铝添加量为10 mL时,底泥体积相对较小,同时上清液浊度大大降低,达到绿色高效的处理要求。

In order to clarify the solid-liquid separation performance of abandoned slurry in shield tunnels and improve separation efficiency,non-ionic polyacrylamide,anionic polyacrylamide,and polyaluminum chloride are selected to study the flocculation and precipitation effects of different molecular weights,concentrations,and addition amounts in this experiment.Based on the experimental results of a single flocculant,a composite flocculant is further selected for experimental research.The results show that the order of flocculation effect from strong to weak is anionic polyacrylamide>nonionic polyacrylamide>polyaluminum chloride,among them,the flocculation and precipitation effect of anionic polyacrylamide is much better than that of nonionic polyacrylamide and polyaluminum chloride,and the mud-water separation speed of organic flocculant polyaluminum chloride is slower than the other two coagulants,but the turbidity of the supernatant is much lower than that of inorganic polymer flocculants.Comparative analysis finds that when the addition of composite flocculant anionic polyacrylamide is 70 mL and the addition of polyaluminum chloride is 10 mL,the sediment volume is relatively small,and the turbidity of the supernatant is greatly reduced,meeting the requirements of green and efficient treatment.