GROUND RESPONSE CURVES FOR ROCK EXCAVATIONS SUPPORTED BY UNGROUTED TENSIONED ROCKBOLTS

LABIOUSE V

V. Labiouse, GROUND RESPONSE CURVES FOR ROCK EXCAVATIONS SUPPORTED BY UNGROUTED TENSIONED ROCKBOLTS, Rock mechanics and rock engineering, 29(1), 1996, pp. 19-38

9

INGLESE

Article

Geosciences, Interdisciplinary","Engineering, Civil

Rock mechanics and rock engineering → ACNP

0723-2632

29

1

1996

19 - 38

ISI

0723-2632(1996)29:1<19:GRCFRE>2.0.ZU;2-2

A numerical analysis has been developed for the design of ungrouted te nsioned rockbolts as support of excavations under axisymmetric conditi ons. The bolts dimensions (length, cross-section, longitudinal and cir cumferential spacings), their stiffness, their pre-tension load and th e delay of installation are taken into account. Moreover, the method e ffects three main improvements in the usual theory, taking into consid eration: 1. the reaction force transferred to the rock mass in the bol ts anchoring zone, 2. the elastic recompression of the carrying ring s urrounding the excavation due to the bolts preload, and 3. the relativ e displacement of the bolts ends which has a repercussion on their ten sion. Since the usual rock-support interaction analysis is only availa ble when the rock mass and the support behave independently, an altern ative solution has been explored for the bolting system (since it cann ot be considered as an internal support). It consists to include the e ffect of the rockbolts into the ground reaction curve. In this paper, the principles of the analysis are explained and a numerical applicati on is taken.