A new rheological model and its application in mountain tunnelling

• Published in: Tunnelling and underground space technology Vol. 23; no. 3; pp. 292 - 299
• Main Authors: Guan, Zhenchang, Jiang, Yujing, Tanabashi, Yoshihiko, Huang, Hongwei
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.05.2008; Elsevier
• Subjects: Applied sciences; Buildings. Public works; Burger-deterioration model; Computation methods. Tables. Charts; Delayed deformation; Exact sciences and technology; NATM; Rheology; Structural analysis. Stresses; Tunnels, galleries; NATM; Delayed deformation; Rheology; Burger-deterioration model; Rheological model; Deformation; Mountain; Deterioration; NATM method; Tunnel driving; Application
• ISSN: 0886-7798; 1878-4364
• DOI: 10.1016/j.tust.2007.06.003

The time-dependent features of soft rock, named rheology generally, should be taken into account in the long-term design and maintenance of mountain tunnels. Based on the classic Burger-MC rheological model, a Burger-deterioration rheological model is proposed in this paper and is implemented in the numerical codes FLAC 3D. A deterioration threshold and two deterioration ratios are introduced in this model to consider the time-dependent strength deterioration aspect of the rock mass. The proposed model is applied to an engineering instance (Ureshino Tunnel Line I, Nagasaki, Japan) to account for the delayed deformations that occurred after its completion since November 1992. The delayed crown settlement and invert upheaval computed from simulations are featured by an exponential characteristic and a stair-typed characteristic, respectively, which agree well with the in-site monitoring data qualitatively. In addition, the realistic rheological parameters involved in the proposed model can be back-analyzed from the in-site monitoring data.