Lessons learned from large failures: multiple causes include adverse design,geology,and support

摘要

Large tunnel and rock cavern spans that have failed for’geological’reasons,or because of design errors,are the main focus of this presentation.The effect of adverse and sometimes unexplored geology will be illustrated.We will need to recognize that pre-investigations might miss some important detail,despite an exceptional frequency of core drilling.Usually,this is of minor importance and does not mean that failure will occur.Being wise after an event,which is always much easier,one might generally question why cross-hole seismics is not performed more frequently to obtain between-borehole information.Prior to construction,the need for this in a particular,but at that time unknown location,cannot of course be foreseen.