Study on groundwater recovery experiment in Mizunami Underground Research Laboratory, 1; Groundwater pressure change in the water recovery process of the underground gallery

Takayasu, Kentaro; Keya, Hiromichi; Onoe, Hironori ; Takeuchi, Ryuji  

The reflood test which fills the part of the tunnel of depth 500m with groundwater is being put into effect for the purpose of exemplification of the recovery ability of the geological environment in the bedrock which was disturbed by construction and operation of large-scale underground facilities, and development of observation and evaluation technique of geological environment recovery at The Mizunami Underground Research Laboratory (MIU). Water pressure observation devices were installed in the tunnel and in each observation section in the surrounding bedrock, and groundwater pressure change in this test was observed. Similarity of water pressure change between the tunnel and each observation section was considered by arranging observed water pressure change data as derivative plots and focusing their shapes.