ANALYSIS OF POTENTIAL CAVE-IN FROM FAULT ZONES IN HARD-ROCK SUBSEA TUNNELS

Authors
Citation
B. Nilsen, ANALYSIS OF POTENTIAL CAVE-IN FROM FAULT ZONES IN HARD-ROCK SUBSEA TUNNELS, Rock mechanics and rock engineering, 27(2), 1994, pp. 63-75
Citations number
9
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Geosciences, Interdisciplinary","Engineering, Civil
ISSN journal
0723-2632
Volume
27
Issue
2
Year of publication
1994
Pages
63 - 75
Database
ISI
SICI code
0723-2632(1994)27:2<63:AOPCFF>2.0.ZU;2-I
Abstract
As a part of a research program on the rock engineering aspects of har d rock subsea tunnelling, analyses of potential cave-in from fault zon es have been carried out at the Norwegian Institute of Technology. Thi s is a topic of great importance for the planning of future subsea tun nels, and particularly for the selection of the minimum rock cover of such projects. The paper is divided into three main parts: a) review o f cases of instability in Norwegian subsea tunnels, b) evaluation of t heoretical maximum sliding, and c) discussion of cases of cave-in in t unnels under land. In theory, a cave-in during subsea tunnelling may p ropagate far higher than the normal minimum rock cover. Taking into co nsideration the comprehensive geo-investigations that are always carri ed out for subsea tunnel projects today, it would, however, be unreali stic to base the dimensioning of rock cover for future projects on wor st-case scenarios. Consequently, the main result of this study is to e mphasize the importance of comprehensive geo-investigations, detailed tunnel mapping, a high degree of readiness during tunnelling and a tho rough quality control.