A new rheological model and its application in mountain tunnelling

Abstract

Abstract: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, aBurger-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 Nov.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.

Predicting Tunnel Squeezing Using Multiclass Support Vector Machines

“…Numerical studies and solutions to time-dependent (or creep) deformations (e.g., [7][8][9]) are not reviewed herein because they are beyond the scope of this study.…”

Predicting tunnel squeezing with incomplete data using Bayesian networks

“…Analytical or numerical solutions to time-dependent (or creep) deformations (see, e.g. Guan et al, 2008;Phienwej et al, 2007;Sterpi and Gioda, 2009) are outside the scope of our analysis and, therefore, they are not reviewed herein. This paper uses Bayesian networks (BNs) to predict the occurrence of squeezing.…”

Rheological parameter estimation for the prediction of long-term deformations in conventional tunnelling

“…From a long-term perspective, however, the long-term deformation mechanism for this mountain tunnel should be clarified. Through numerical simulations, Guan et al (2008) …”

“…The constitutive laws of Burger-MC deterioration rheological model are introduced briefly in this appendix, which is based on Guan et al (2008). The deviatoric behavior can be schematically illustrated In the above equations, e ij and s ij are the deviatoric strain and stress tensors; ε kk and σ kk are the volumetric strain and stress.…”

“…These time-dependent features, named rheology in general, have been studied carefully through a great deal of specified creep, relaxation and quasistatic compression tests (Maranini and Brignol, 1999;Nawrocki et al, 1999;Li and Xia, 2000;Shin et al, 2005;Fabre and Pellet, 2006). According to the results from laboratory (or in-situ) tests and the experience from engineering practice, many rheological models have been proposed to account for the time-dependent features of rock mass from manifolds (Hudson and Harrison, 1997;Jin and Cristescu, 1998;Pellet et al, 2005;Shao et al, 2006;Guan et al, 2008). For a certain engineering instance, however, it is not easy to determine an appropriate rheological model and its corresponding rheological parameters due to the high cost and the long duration of rheological tests.…”