An account of tunnel support systems for soft rock mass conditions

摘要

Subsurface works such as tunneling especially in soft rock require support, often immediately upon excavation. Support systems usually comprise of several individual components provided to suit the specific site's soft rock mass conditions. Rock mass conditions are classified according to strength, degree of weathering and discontinuities; based on empirical method applications for hard rock. The rock mass conditions hence rock class and hydrogeology are key inputs to tunneling and tunnel support systems. From the design process appropriate parameters of the support components, comprising a support system, are suggested. Research on tunneling in soft rock is evolving. Existing research and information highlight the need for further research on soft rock, including establishing its own rock mass classification system. It is upon this ground that this study discusses soft rock rather than hard rock. This paper reports on tunnel support systems in soft rock from related experiences and research. In summary, the need for further research on the subject of soft rock and constructing in it is apparent.