ABSTRACT:

In this paper, the analytical method and its computer program to consider the influence of dispersion of the mechanical properties were developed, and in order to clarify the influence of its dispersion, the numerical simulation of in-situ rock shear test and the analysis of rock foundation of a large structure were performed. The results are as follows:

  1. The applicability of the developed program was confirmed by the comparison between the calculated values and the measured values.

  2. The influence of the dispersion of the mechanical properties of rock mass used to the stability analysis does not appear notably to the settlement and sliding safety factor of the structure foundation.

  3. The design considered the dispersion of mechanical properties can carry out sufficiently by the method using the deterministic values from the results of analytical parameter survey.

In this case, the values of mechanical properties should be evaluated as [X (mean value) ± K (coefficient) × σx (standard deviation)].

RESUME:

Pour eclaircir les influences de la dispersion des valeurs physiques du sol sur la stabilite du sol, nous examinons les methodes d'evaluation sur la dispersion des valeurs avec le developpement d'une methode analytique et son logiciel, l'essai in situ tenant compte de la dispersion des valeurs et l'analyse de la stabilite du rocher de fondation support ant des ouvrages importants. En consequence:

  1. nous avons pu verifier l'aptitude du logiciel mis au point "RASRM" par la simulation numerique de l'essai in situ de cisaillement des roches;

  2. les influences de la dispersion des valeurs physiques du sol sur les paramètres d'evaluation tels que le glissement et le tassement ne sont pas importants par rapport à la largeur de la dispersion et à la forme de distribution des valeurs physiques utilisees pour l'evaluation;

  3. nous avons qu'une des methodes de theorie de certitude peut être appliquee comme methode de conception tenant compte de la dispersion des valeurs physiques qui presentent seulement des caracteristiques de dispersion; {(valeur moyenne) ± (coefficient) × (deviation standard)}.

ZUSAMMENFASSUNG:

Es wurden die Entwicklung einer analytischen Methode and derer Programms, einen Baustellenversuch mit Rūcksicht auf die Dispersion sowie eine Stabilitàtsanalyse des Grundfelsbodens fuer die wichtigen Bauwerke u.a. durchgefuert, um die Beeinflussung der Dispersion von den Bodenmaterialwerten auf die Bodenstabilitatabzuklaren. Daraus ergaben sich die folgenden Punkten:

  1. Die Gueltigkeit des entwickelten Programms "RASRM" wurde durch eine nummerishe Verstellung des Baustel enfelsschubversuchs festgestelit.

  2. Die Beeinflussung der Dispersion von den Bodenmaterialwerten auf die Schatzungsstuecke z.B. Gleiten und Setzung des Bodens ist klein im Vergleich zu der groβen Dispersion und Abweichung der zur Schatzungverwendeten Materialwerten und Vertellungsformen.

  3. Auf den Entwurf kann die Wahrscheinlichkeitsrechnung gut angewendet werden. Dabei sind die einzusetzenden Materialwerte in der folgenden Form auszudruecken, damit das Verhalten der Dispersion beruecksichtigt wird: Materialwert = (Mittelwert) ± (Koeffizient) × (Normalabwelchung).

1 INTRODUCTION

The values representing the physical and mechanical properties of rock mass are usually obtained with some dispersion even on the same type and quality of a rock at the same point. Accordingly, it is necessary to naturally consider the influence of the dispersion of the values of mechanical properties in investigating the stability of the rock foundation in important structures or large slope. To consider the influence of the dispersion of mechanical properties, there appears the following two methods;

  1. the method treating the individual value of mechanical properties as a random variable (referred to hereafter as the probabilistic method).

  2. the method using the representative value of the data as mechanical properties (referred to hereafter as the deterministic method).

That is, the former method considers the distribution properties as being directly incorporated into the estimating method, while treating the individual value of mechanical properties as the random variable following the probability distribution. The latter is the method analyzing the representative value (mean value or the most frequent value) or the allowable constant value used, while considering the fluctuation latitude of the dispersion of the individual value of mechanical properties. However, the relation between both methods concerning the influences exerted on the results of the stability analysis by the dispersion of the mechanical properties of rock mass has not been made clear. Therefore, we developed in this study a finite element method program describing the non-linear mechanical properties while treating the mechanical properties as a random variable, to quantitatively clarify the influence of the dispersion of mechanical properties exerted on the stability analysis of rock mass. Moreover, a case study is performed to examine the influence which is exerted on the settlement and sliding safety factor of an important structures, according to both the probabilistic and deterministic methods along with parameters of the distribution properties of the spatial dispersion of mechanical properties by using the developed program.

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