ABSTRACT:

It is very important to predict the stability around openings in rock engineering. However, the input parameters and the results of present prediction methods mostly depend on the experiences of engineers. In this paper, considering these difficulties, a new prediction method is presented. First, a Grey system differential equation which can describe the deformation process of surrounding rock is set up, and a deformation forecasting model can be obtained. And then based on the forecasting displacements and probability back analysis, rock property parameters are back-analyzed. Thirdly, by use of these parameters in future, reliability analysis of finite element method can predict the stability in probability values. Lastly, a practical coal mine roadway example shows that the proposed method is a good one.

RÉSUMÉ:

En ingenierie des roches, la prevision des carasteristiques de stabilite des roches englobantes releve dúne importance capitale. Jusqu'à present, ces carasteristiques s'obtiennent essentiellement à partir de parametres de donnees empiriques et les resultats obtenus varient selon que l'imgenieur soit plus ou moins experimente. Nous proposons donc dans notre artiele une nouvelle methode plus sûr. D'abord nous representons Ie processus des deformations de la roche encaissante par un systeme gris d'equations differentielles, de là nous pouvons obtenir un modele des deformations previsibles. Emsuite, sur cette base mous feroms une analyse inver, se des probabilitites et des deplacements prevus et une analyse inverse des parametres carasteristiques de la roche. Puis nous utiliserons ces parametres à vemir pour prevoir, par la methode d'analyse du degrè de certitude des elements finis et compte tenu des valeurs de probabilite, les proprietes de stabilite. Enfin, nous allons donner un exemple dapplication de notre nouvelle methode dans le cas particulier des galeries d'un minerai de houille.

ZUSAMMENFASSUNG:

Es ist im felsenwesen sehr wichtig, die stabilitat des umgebenden felsea zu prophezeisen. Aber zur zeit sind die eingangsparameter und resultate der propherzeiungsmethode abhangig von den inginierserfahrungen. In dieser arbeit sind solche schwierigkeiten ueberlegt und wird eine neue propherzeiungsmethode gestellt. Zuerst, die differentialen gleichungen eines grausystem, das den deformierungsvongang des umgebnden felses beschreiben, werden gegrundet, daraug entsteht ein propherzeiungsmodell fur diesen deformierungsvongang, und dann werden die felseigenschaften durch die vorhengesagte verschiebung und die probabilitat ruckanalyse ruckanalysient. Drittens, mit solchen parametern in zukunft kann die zuverlassigkeitganalyse der finite elementsmethode durch den wahnscheinlichkeitwert die stabilitat propherzeien. Letzteng, ein beispiel eines kohelentunnels bestãitigt, dap die vorliegende methode sehn gut ist.

1 INTRODUCTION

It is very necessary to estimate the present and future stability condition of surrounding rock in rock engineering. Thus, the prediction theory of stability around openings comes into the field of rock mechanics. Up to now, many prediction methods have been proposed which can be categorized as follows:

  1. Experience analogy methods, such as J. Scki & M. Okada (1988), A. Guenot & M. Panet(1985), M. Matsuo & K. Kawmura(1980) have contributed to this field, moreover many in-situ engineers have proposed the regression methods and analogy predictions;

  2. Mechanics model methods, these methods are mostly used to investigate the evolution of the time-dependent deformation with the help of the rheology theory, such as M. Panet (1979), Wang Zhiyin (1988) et al;

  3. Numerical analysis methods, such as finite element method and boundary element methods, which are used to analyse present or future deformation evolution behavior, as I.G. Vardoulakis (1988), Huang Hongwei (1990) et al;

  4. Process model methods, which consider deformation evolution as a stochastic process or dynamic process to model it using these corresponding mathematics theories as D. B. Ashey (1980), Chen Zhiyin (1988), Liu Huaiheng (1900) et al;

  5. Combined prediction methods, which include expert system, fuzzy combined prediction, such as Huang Hongwei (1990) et al.

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