隧道開挖變形之二維分析

A 2-D Deformation Analysis of Tunnel Excavations

陳昭旭(Chao-Shi Chen) ； 楊威秋(Wei-Chiu Yang) ； 黃俊銘(Jun-Ming Huang)

《鑛冶：中國鑛冶工程學會會刊》 44卷3期 (2000/09) Pp. 139-148

https://doi.org/10.30069/MM.200009_44(3).0012

摘要

現今分析隧道開挖行為的數值方法中，對於地下岩體內的節理，一般有兩種處理方式；一是將岩體內節理視為岩體內的一部份，即利用降低岩體本身之強度，以模擬節理在岩體內之狀兄，即所謂『連續性分析方法』。另一方法是將岩體內的節理視為獨立個體，把節理的強度、方位和間距等因素均呈現在模擬分析上，即所謂的『不連續性分析方法』。本文利用目前隧道工程界最常用的兩套二維數值分析軟體－FLAC和UDEC，分別代表連續性和不連續性數值分析方法，來探討隧道開挖二維度變形行為。使用FLAC作隧道開挖變形模擬分析，並以鯉魚潭頭水隧道與新天輪引水隧道為研究案例，探討岩盤RMR值與隧道開挖面最終變形量之關係。在UDEC方面，利用假設一圓形斷面隧道，在固定其節理力學參數與節理組數條件下，來討論節理傾角及間距對隧道變形的影響。

關鍵字

隧道開挖 ； 變形 ； 數值分析

並列摘要

In the recent years, there are mainly two numerical approaches which have been used for modeling the deformability of rock tunnel excavations. The first is the continuous analysis which represents the jointed rock mass as an equivalent continuum by softening the mechanical properties of the rock. In the second approach, called discontinuous analysis, the rock mass is treated as a discontinuum due to joints, faults and bedding planes. A variety of discontinuity behaviors need to be considered in this approach, such as deformation and strength properties of rock joints, the orientation and spacing of joints, and seam properties, etc. In this study, we use two software packages called FLAC and UDEC which represent the continuous and discontinuous analysis methods respectively, to be the numerical analysis tools. The two dimensional deformability of rcok mass in tunnel excavations was determined by the two packages. The experimental results of two case studies on tunnel excavations, i.e. Liyutan headrace tunnel, and Hsintianlun hydraulic tunnel, are introduced to compare with those by the numerical analysis. A limitation about numerical analysis methods is also presented in this paper.

並列關鍵字

Tunneling ； Deformability ； Numerical Analysis