英文篇名
REVIEW ON UNDERGROUND EXCAVATION SUPPORT DESIGN
作者
張吉佐
摘要
台灣地窄人稠且地理上大部份為山岳及丘陵帶,隨看時代之進展,將必有大量地下岩石開挖工程。在地下如何順利且經濟的挖出空間,有賴吾人對岩盤之走向、弱面之分佈、地壓之大小與方向等之充分瞭解;同時選擇合適之開挖斷面形狀、施工方法以及合理之支撐。岩盤走向、弱面分佈及地壓等均屬大地既有之現象,對整體影響不易變更;開挖斷面與施工方法亦往往受外在因素之限制。因此,本文將回顧地下岩石開挖工程之支撐設計。
根據新近岩石力學之發展,地下岩石開挖工程支撐設計之基本原理為利用支撐激發及維持岩體與天具有之強度並協助岩體自立。
英文摘要
The paper points out that the potential failure modes in underground excavation consist of stress induced failure, structural type failure, excessive ground water inflow and unfavorable alteration. It is noted that appropriate design of support system is required to stabilize all failure modes, except for the excessive ground water inflow which needs drainage or grouting.
The principal objective in the design of underground excavation support is to help the rock mass to support itself. Rock reinforcement is the best solution.
Three approaches, i.e., empirical methods of design, analytical methods of design and observational methods of design, are currently widely applied as underground support design. However, the final support design should only be decided after excavation, i.e., once the true rock conditions are exposed. An example to illustrate how support design can be done using empirical method is given in the paper.