Abstract:

High groundwater level is a most essential factor that threatens the safety of linings in large-scale, long-distance water diversion channels. Particularly when such channels traverse foothill plains, the lining stability is highly influenced by groundwater fluctuations in the foothill transition zone. A typical excavation channel section from the middle route of the South-to-North Water Diversion Project was taken as a case study. By utilizing groundwater monitoring data and a three-dimensional seepage model, we examined how groundwater changes affect the stability of the channel lining in line with the geological characteristics of foothill plain. For the first time, we elucidated the feedback relationship between water supply channel and groundwater in foothill plain and proposed relevant countermeasures. Our findings reveal that the channel intersects the surface permeable layer of foothill plain, creating a water-blocking effect. Rainfall and runoff from the foothill elevate the groundwater level between the foothill and the channel, directly resulting in uplift and damage of lining plate. The results offer theoretical foundation and technical support for designing, operating, and maintaining water diversion channels in similar foothill plain regions and for managing associated risks.

Key words: water diversion channels, foothill plain, high groundwater level, lining damage, seepage analysis