Investigation on collapse mechanism of super-deep vertical shaft

Sakurai, Shunsuke*; Shimizu, Norikazu*; Akutagawa, Shinichi*; Yoshida, Hidenori*; Sato, Toshinori  ; Yamachi, Hiroshi*

Recent interests in the development of deep underground facilities have been drawing significant attention for the importance of vertical shafts at great depth. However, due to shrinkage of domestic coal production, any deep shafts in the order of 1000 m have not been constructed in more than 20 years. For the purposes of technical transfer and establishment of fundamentals for rational design method of vertical shafts, intensive literature review and interviews to engineers with relevant experiences were conducted. As the results, there are two distinctive modes of failure mechanism originated by the common cause, that is "takanuke" and lining failure due to unexpected earth pressure.