荆江大堤观音寺堤段减压井灌淤现场试验研究

In-situ Investigation on Colmatage in Relief-wells at Guanyinsi Section of Jingjiang Dike

本文阐述在荆江大堤观音寺堤段进行的现场灌淤试验。通过对地下水动态的分析,阐明减压井中氧化还原电位和溶解氧含量随江水位的变化规律,由于荆江大堤的特定工程地质、水文地质条件以及长江水流动态决定了荆江大堤堤基减压井灌淤的发生和发展。由此提出在汛期高水位时流向井的水只来自江水,汛期减压井应全部投入运行。文中列举渗流量的变化,氧化还原电位的分布以及试样各部位铁含量的变化等,论证所提电化学方法是一种防治减压井灌淤的有效方法。文中还提出,为防止减压井失效,应选择适应荆江大堤特定水文地质条件的材料以及尺寸等。

This paper reveals the in-situ colmatage testing performed at Suanyinsi section of Jingjiang Dike. Through analysis of seepage flow regime, the variation of oxido-reduction potential and dissolved oxygen content in relief-well with river level are clarified. From this we come to the conclusion that the occurence and development of Colmatage in relief-well on dike footing depend on the special hydrogeo-logical condition and the river regime. Then, it is proposed that as water flowing into the well is only from the river at high water level, the relief-wells should be fully put into operation during flood season. In this paper, the variation in seepage flux, the distribution of oxido-reduction potential and the ferrite content of test sample at each position have been dealt with. These results prove that the electro-chemical method proposed is efficient in controlling colmatage in relief-well. In order to avoid relief-well out of operation, it is suqqested that the materials and size suited to the special hydrogeologi-cal condition of Jingjiang Dike should be selected.