ABSTRACT

In this paper, the stability evaluation and bifurcation criteria are presented for the Jinping arch dam structure. The bifurcation models in failure status of the arch dam are derived from the uniqueness of the controlling equation of dam behaviours, and the relative phenomena between positive definition of dam structural tangent stiffness and bifurcation are given in the paper. Then the structural collapse criteria for arch dam are discussed based on the energy mode. A stability criterion of dam based on the connection of yield zones is proposed according to the implementation of elasto-plastic FEM (finite element method) numerical analysis. In accordance with this judging method, nonlinear FEM analysis is used for Jinping arch dam. The failure process of the Jinping dam was simulated and yield zones were found under the overloading condition.

ZUSAMMENFASSUNG

In der Verliegenden Arbeit wird ein integrater geomechanisch Modellversuch fuer Jinping Bogenstaumauer Vorgesstellt. Die Bogenstaumauer liegt aut der komplizerten felsformationen. Der Zerstoerungsmechanismus, die Stabilitaetsfaktoren und die Interaktion zwischen der Bogenstaumauer und den Seiltichen. In der Vorliegenden Arbeit wird eine dreidimensionale finite element analyse fuer die seitlichen. Gestein sauflager mittels dem Bruchmodell Vorgestellt, da fuer Jiniping Bogenstaumauer angewandet wird. Ein Bruch mechanismus model einschliesslich der statistischen parameter der Gesteinfes tigkeit wird entauckeit.

RÉSUMÉ

Das ce documènt a ete faite une analyse d'elemt limite de trois dimensions dn fondement de construction de roche faisant appel au modele de l'endommagemnet à fracture, analyse appliquee an fondement du bar ragevoute de Jinping. Ce documènt decrit le test de modele geomecanique integral pour le barrage-voûte de Jinping L'ampleur du modele en question constitute l'une de plus importantes en China. Ils correspondent par faitement anx calculs des resultats.

Introduction

Overloading safety factors of arch dam are considered in engineering science. Therefore, in overloading calculation, judgment of failure behaviours for arch dams is worth researching. In this paper, bifurcation and collapse criteria of overall stability of arch dam are studied by using the uniqueness of bifurcation, and stability of equilibrium and bifurcation criteria are discussed based on the energy mode. Jinping arch dam is presented as an engineering sample on yielding zone development of arch dam structure.

Bifurcation criteria of localization failure

Expression of elasto-plastic constitutive relation under plastic loading is given below

(Equation in full paper)

Evaluation of overall stability of dam structures in numerical calculation

Evaluation of stability in civil engineering, which may be influenced by many external factors, is quite complex and difficult, even undependable. Judgment of overall stability can be realized through the method given below.

Evaluation of iteration convergence in numerical calculation

If the qualification satisfies ΔF > 0, Δδ →∞, elastoplastic iteration appears divergence, and the structure is considered as failure. In other words, an equilibrium status cannot be achieved in the iterative process.

Evaluation of overall stiffness singularity based on energy criterion

If external work Π R is not larger than increment of internal energy P, civil engineering system is regarded as stable.

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