Approaches for modelling transient unsaturated-saturated groundwater flow during and after construction

飽和-不飽和問題における非定常地下水流動解析について

White, M. J.*; Guimer, J.*; 大山 卓也 ; 小坂 寛; Robinson, P.*; 三枝 博光

White, M. J.*; Guimer, J.*; Oyama, Takuya; Kosaka, Hiroshi; Robinson, P.*; Saegusa, Hiromitsu

複雑な水理地質環境における地下水流動解析の効率的なモデル化・解析を実施するため、これらを一貫して行うことができるGEOMASSシステムを開発している。本システムを用いて、坑道掘削に伴う飽和-不飽和問題での地下水流動場の変化に関するデータに基づく水理地質構造モデルの更新及び今後の変化を予測するために、地下水流動解析コードの改良を実施するとともに、改良した解析コードの信頼性確認のために、検証済みの解析コードと同一条件下での解析を実施した。

JAEA has been developing modelling techniques to overcome these problems as part of the Mizunami Underground Research Laboratory. An integrated geological and hydrogeological modelling, and visualization system referred to as GEOMASS has been developed, which allows for transient unsaturated groundwater flow modelling in the presence of dynamic underground excavation models. The flow simulator in GEOMASS, FracAffinity, allows for such modelling by the application of sophisticated gridding techniques, allowing for modification of hydraulic conductivity in key zones, and by suitable modification of water retention models. The approaches that have been developed in GEOMASS have been tested through a series of models of increasing complexity, and the testing has demonstrated that there is no significant impact on estimates of regional groundwater flows or local estimates of flow into underground excavations.