减压井化学淤堵试验研究

针对长江堤防典型的地层砂样，采用砂砾石和聚氨酯作为反滤料，利用葡萄糖溶液模拟地层中的还原条件，开展了反滤试验；并结合对实际减压井运行的观察，分析研究了化学淤堵的机理。地层中的含铁矿物处于还原条件，在减压井自流排水时，被溶解的铁离子向井内运移，在井口或水面附近形成高价铁化合物，吸附于井壁，或悬浮于水中。在减压井停止排水时，氧化作用进一步加剧， 高价铁化合物向井结构内运移和吸附沉淀，逐渐造成减压井的淤堵。这种铁离子来源于地层，氧化于水面，又吸附沉淀于井结构的过程，说明了化学淤堵具有溯源特性。

Experimental Study on Chemical Clogging of Relief Well

Seepage tests were performed for the sand sample from typical strata beneath Yangtze River dyke, with grit gravels and a polyaminoester as filter materials, and with dextrose liquor to simulate deoxidization in the stratum. On the basis of the test results and site investigation, the chemical clogging mechanism was analyzed. Ferric mineral in the stratum is deoxidized. While the relief well works as an artesian well in flood season, ferrous ions would be transported toward the well structure and are oxidized to ferric compound at outlet or near the water surface. The compound would be absorbed by the well wall or suspend in the water. While the well drainage stops, oxidization would speed up in the well, ferric compound would moves into the well structure and deposits inside it. So the well would be clogged gradually. This process that the ferrous ions come from the stratum, change to ferric compound and then move back to well structure reveals one of the characteristics of chemical clogging, namely, tracing to source.