かみ合わせと固着を考慮した岩石不連続面の限界状態モデル

Abstract

岩盤の崩落や滑動を回避して地下開発を行うためには，岩盤の弱部となる不連続面のせん断特性を精緻に記述できるモデルに基づいた応答予測が必要である．そのためには不連続面の幾何学的形状やかみ合わせ，固着状態といった性質を適切に考慮する必要がある．そこで本研究では，土のモデルに適用されてきた限界状態論を応用して定式化された岩石不連続面の弾塑性モデルが不連続面のかみ合わせの違いを考慮できるか検証するために，初期のかみ合わせのみが異なるせん断試験の解析を行った．次に，このモデルを不連続面の固着特性も考慮できるように拡張し，せん断と保持を繰り返すせん断試験の解析により，提案モデルが固着の発達に伴う応力の回復を表現できることを明らかにした．

In order to develop underground structure without rock mass collapse or slippage, it is important to construct a constitutive model that can accurately predict the strength and deformation characteristics of rock joint, which are weak areas of the rock mass. For this purpose, it is necessary to consider the geometry of the rock joint's surface and their matching and adhesive conditions. Therefore, in this study, we conducted whether existing the elasto-plastic model of rock joint based on the critical state concept applied in the Cam-Clay model etc. can take into account differences in matching condition of rock joints, and demonstrated their applicability by analyzing shear tests in which only the initial matching differs. In addition, a new state variable was introduced into the model to take into account adhesion condition, and we conducted the analysis of shear tests with repeated shearing and holding to show that the model is capable of representing stress recovery associated with the development of adhesion.