基于遇水膨胀橡胶的分层抽水管外止水新方法及其优化

分层抽水试验是水文地质勘探的重要技术内容。针对传统分层抽水管外止水方法效率低、可靠性及可控性差等难题，利用聚丙烯酸钠树脂的高吸水特性，开发了遇水膨胀橡胶，提出一种基于遇水膨胀橡胶的管外止水新方法，并采用响应面法对该新方法进行了优化研究。以吸水膨胀率为响应指标，通过Box-Behnken试验设计构建代理模型，探究不同工艺、工况参数及其交互作用对橡胶吸水膨胀性能的影响，达到优化工艺、预测工况的双重目的。结果表明:遇水膨胀橡胶的最佳工况和工艺参数组合为水溶液pH值7.0、吸水时间136 h、聚丙烯酸钠添加量61份、改性芳纶短纤维添加量4.5份。最后，研制了基于遇水膨胀橡胶的管外止水装置，经试验验证了所提方法的可行性，对地下水资源勘探利用具有工程应用价值。 

New method and optimization research on water sealing outside casing based on water-swelling rubber for stratified pumping

Stratified pumping test is a key technique for hydrogeological exploration. To solve the problems of low efficiency and poor reliability and controllability of the traditional water-sealing methods outside casing for stratified pumping, a water-swelling rubber was developed based on high water absorption of the sodium polyacrylate resin, and a new approach based on water-swelling rubber was proposed and optimized by the response surface methodology in this paper. With the water swelling ratio of the rubber as response index, a surrogate model was constructed by the Box-Behnken experimental design to study the influence of different process parameters, working condition parameters, and their interaction on the water-swelling performance. Furthermore, the preparation process of water-swelling rubber was optimized and its working condition was predicted. Optimization results indicate that the optimum combination of working conditions and preparation process parameters of water-swelling rubber includes aqueous solution at pH 7.0, water absorption time of 136 h, sodium polyacrylate 61 phr, and modified aramid short fiber 4.5 phr. Finally, the water-sealing device outside casing was developed, and the feasibility of the proposed method was verified through experiments, which has engineering value for the exploration and utilization of groundwater resources.