富水砂卵石层堵漏凝胶的研制及其机理

Development and mechanism of plugging gel for water-rich sand and gravel formations

摘要:

针对富水砂卵石层地下连续墙施工过程中槽壁发生垮塌，而常规堵漏材料（如水泥）并不十分适用的问题，通过单因素试验分析了成胶剂（阴离子聚丙烯酰胺）、交联剂（铬交联剂）、增强剂和粘土对浅层堵漏聚合物凝胶性能（成胶时间、粘度、强度、稳定性）的影响，并利用正交试验得到了最终的优化配方，同时分析了该凝胶材料的形成机理。结果表明：增强剂能够在凝胶内串联成胶剂，进一步增强凝胶强度和稳定性；而粘土同样能够缩短交联时间、增强凝胶体强度，但粘土不利于浆液的稳定性，稍微过量便导致浆液分层。最终的优化配方为：15%铬交联剂+5%成胶剂+8%增强剂+7.5%粘土，测试其性能能够满足地下连续墙浅层堵漏的要求。

关键词:富水砂卵石层;地下连续墙;浅层堵漏;堵漏凝胶;聚合物凝胶

Abstract:

In view of the collapse of the trench wall and the failure of conventional plugging materials such as cement in the construction of diaphragm walls in water-rich sand and gravel formations， single factor experiment was used to analyze the influence of the gel forming agent （anionic polyacrylamide）， the crosslinking agent （chromium crosslinking agent）， the reinforcing agent and clay on the properties of polymer gel （gelation time， viscosity， strength and stability） for shallow plugging； and the optimum formulation was obtained by orthogonal test. In addition， the formation mechanism of the gel material was also analyzed. The results show that the reinforcing agent can link the gel-forming agent in gel， and further enhance the strength and stability of gel. Clay can also shorten the cross-linking time and enhance the gel strength， but clay is not conducive to the stability of the slurry. The final optimized formula is： 15% chromium crosslinking agent+5% gelling agent+8% reinforcing agent+7.5% clay. Its performance can meet the plugging requirements of shallow diaphragm walls.

Key words:water-rich sand and gravel formations;diaphragm wall;shallow plugging;plugging gel;polymer gel