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

Abstract

The long-term deformations of mountain tunnels, which attract more and more attentions, are closely related to the time-dependent features of the surrounding rock mass. However, it is not easy to determine an appropriate rheological model and its corresponding parameters for a certain engineering instance. This paper presents a rheological parameter estimation technique by using error backpropagation neural network (BN) and genetic algorithm (GA). The application of the proposed technique to an engineering instance, Ureshino Tunnel Line I on Nagasaki Expressway, is expatiated in detailed. The stochastic nature of the proposed technique is also discussed through case studies. It is proved that the proposed technique can provide the engineer with an optimal estimation of the rheological parameters, which can help the prediction of long-term deformations of mountain tunnels in the future.

Test on cyclic creep behavior of mucky clay in Shanghai under step cyclic loading

“…Boulanger and Idriss (2007) gave a kind of method to evaluation the potential for cyclic softening. Guan et al (2009) estimated the rheological parameter for the prediction of long-term deformations in tunneling. However, most of these researches are focused on the residual deformation prediction in the long-term cyclic loading, and little attention was paid to the essential characteristic and variation of clayey creep.…”

Estudio de la fluencia de una calcarenita: la Piedra de San Julián (Alicante)

“…La deformación instantánea se ha restado de la deformación axial total. El módulo de Young (E r ) y el coeficiente de Poisson (ν) han sido calculados con las ecuaciones [2] y [3].…”

“…This phenomenon has been studied and modelled by several authors, although the volume of existing literature on rocks is much lower than for concrete creep phenomena. Some studies are focused on developing techniques for the building and maintenance of tunnels, using rheological or constitutive models (1,2). Other researchers study the impact of creep on rock masses by measuring the deformations in excavations and proposing a model for reproducing their behaviour (3), or based on laboratory studies of intact rocks samples and rheological models for predicting the creep deformations (4).…”

“…Este fenómeno ha sido estudiado y modelado por varios autores, aunque el volumen de referencias existentes sobre rocas es mucho menor que para los fenómenos de fluencia en hormigón. Algunos estudios se centran en el desarrollo de técnicas para la construcción y mantenimiento de túneles, utilizando modelos reológicos o ecuaciones constitutivas (1,2). Otros investigadores estudian el impacto de la fluencia en macizos rocosos mediante la medición de las deformaciones en las excavaciones y proponen modelos para reproducir este comportamiento (3) o, basándose en estudios en laboratorio de muestras de rocas intactas, proponen modelos reológicos y predicen las deformaciones de fluencia (4).…”

A Simple Genetic Algorithm for Calibration of Stochastic Rock Discontinuity Networks

“…Guan et al 2009;Levasseur et al 2008Levasseur et al , 2010, identification of critical slip surfaces in slope stability (see e.g. Zolfaghari et al 2005;Xue and Gavin 2007;Fahd and Jimenez 2008) and the reliability of finite elements (FE) designs (Cui and Sheng 2005).…”