Failure and Triggering Mechanism Analysis of the Bitchu-Matsuyama Castle Rock Using Distinct Element Method

Abstract

岡山県中央部の高梁市にある備中松山城の大手門岩盤においては落石, クラックの進行, クリープ挙動が現れ, 対策工の必要性が指摘されている.この岩盤斜面について崩壊誘因と崩壊メカニズムについて検討した.風化の進行, 斜面末端の地すべり運動, および風によるクラックに貫入した樹根による揺さぶり等の諸要因による影響を解決するために離散要素法(DEM), 特にUDECプログラムを用い, 節理面に沿ったせん断変位に注目してシミュレーションを行った.さらに現在設置中の監視システムの最適化のための岩盤斜面の今後の挙動予測を行った.

In this paper a rock slope failure of Bitchu -Matsuyama castle rock located near Takahashi city in the central part of Okayama prefecture is presented. Rock mass creep movement, which mechanism and triggering factors are studied here, endangers the castle, which walls are suffering damage and need to be repaired.In order to find the reason of the damage various triggering factors such as weathering progress, slope -toe erosion (toe sliding) and a special phenomena for this site - wind tree action are simulated using distinct element method (DEM), namely UDEC (Universal Distinct Element Code) as one of the numerical modeling codes.The joint shear displacements of several points are observed in the model as key factors for result comparison. Further a failure analysis of rock slope is carried out in order to find out the future behavior of the rock slope and optimize the design of monitoring system, which is in process of installation.