水溶性高聚物在盾构隧道注浆材料中的应用研究

研究了羧甲基纤维素、聚乙烯醇和聚丙烯酸钠三种高聚物对掺高效减水剂GCL1—3A的盾构隧道注浆材料泌水、流动度、凝结时间以及水泥净浆流变性的影响，结果表明，羧甲基纤维素和聚丙烯酸钠对注浆材料都具有良好的保水性，聚乙烯醇在6h后才显示出一定的保水效果。在3％（质量分数）掺量（相对于减水剂用量）下，羧甲基纤维素和聚丙烯酸钠可提高注浆材料的流动度和稳定性。此外，羧甲基纤维素和聚丙烯酸钠具有促凝作用，而聚乙烯醇具有缓凝作用。掺加羧甲基纤维素或聚丙烯酸钠的注浆材料初凝时间均为13h左右，比未掺加高聚物的注浆材料的初凝时间缩短了1h。

Study of Water-Soluble Polymers Used in the Grouting Material for Shield Tunnel

The effects of carboxymethycellulose (CMC), polyvinyl alcohol (PVA) and sodium polyacrylate (PNaAA) on the properties of the grouting material used in shield tunneling, such as the quantity of water seeping, the fluidity, the setting time and the rheology of cement paste, were investigated. In this investigation, a high-efficiency water reducer GCL1-3A was mixed into the grouting material. The results reveal that (1) CMC and PNaAA possess excellent water-retention property for the grouting material, while PVA does not display this property till six hours later; (2) with the usage of 3%(mass fraction) in the water reducer, CMC and PNaAA can enhance the fluidity and stability of the grouting material; (3) CMC and PNaAA can accelerate the concreting of the grouting material while PVA is of the opposite effect; and (4) the original setting time of the grouting material with CMC or PNaAA being added is about 13h, which is 1h shorter than that of the grouting material without any polymer being added.