成層岩盤の内部崩壊に関する基礎的研究

Abstract

In order to investigate the internal failure in various stratified rock due to the localyield such as the local failure caused around the excavated tunnel, a model test wascarried out by using a pile of blocks made of vinyl chloride. In the model test, theblocks was piled up in the horizontal, inclined and vertical strata and the internal failurein the stratified pile was simulated by gradually lowering a panel which forms a part ofthe horizontal base under the pile of blocks.From the test results, it is observed that the failure zone may be classified into theprimary failure zone which usually accompanies the lowering of the panel and the secon-dary failure zone which appears around it under a certain condition. Then the relationto determine the condition is studied. This condition is influenced by D/B (D: depthof the blocks, B: width of the lowering panel) and the critical values of D/B belowwhich the secondary failure zone appears are obtained from the consideration of thefailure mechanism. Furthermore the stability for the development of the failure zonecaused by a litte disturbance is discussed.