【企画講演／募集型企画】 YARO15 −コロナ禍での岩盤工学に関する研究−

[3K0109-13-01] （学生発表：修士課程） 露天掘り石灰石鉱山の残壁の変形挙動に与える断層と弱層の影響

○張 誠¹、アマグ　クレメント アマグ¹、児玉 淳一¹、才ノ木 敦士²、小川 智史³、梅田 知佳³、藤井 義明¹、福田 大祐¹ (1. 北海道大学、2. 熊本大学、3. 菱光石灰工業株式会社)

司会：佐藤 晃（熊本大学）

キーワード：石灰石鉱山、残壁、安定性評価、個別要素法、断層

This study takes an open-cut limestone quarry in Japan as an example to discuss the mechanical interaction between two specific geological structures. In this quarry, below the mining area is a vertical fault intersecting with a weak rock formation almost parallel to the slope surface. Based on the unique geological structures, numerical simulations are conducted using discrete element method to elucidate the impact of two geological structures. The analysis results show that the vertical fault and weak rock formation significantly impact the rock slope deformation in mining progression. In the cases of an excavation-only model without geological structure, the slope surface deforms backward direction. However, in the fault and weak rock formation model, as the mining face crosses the fault, apparent forward slip occurs along with the weak rock formation. In this model, although the vertical fault constrains the sliding of the upper discontinuities at the early stage, the normal stress of the weak rock formation decreases gradually as the mining progresses, and local shear failure occurs at the intersection of the weak rock formation and fault, which leads to the slip. Furthermore, rock slope displacement due to the slip gradually decreases and eventually stabilizes as the working face gets away from the vertical fault, which means the slope eventually stabilizes. This study provides new insight into the deformation mechanism of the rock slope and serves as a reference for future mining and slope prevention work.