Abstract

Study on nonlinear damage localization process of rocks under water chemical corrosion is a more interesting topic in rock mechanics research world widely. It is very important in estimating long term stability of rock engineering, design of nuclear waste repository and its performance estimation, geothermal and petroleum development. This paper reports that new development of study on the topic, including methodology, results of meso-mechanical test, real-time CT scan test and acoustic emission test, temporal fractal behaviors, neural dynamic modeling and chemical-induced damage law, etc. This paper also discusses the research directions of the topic in the near future.

Zusammenfassung

Untersuchung zum durch die chemische Corrosion induzierten Schaedigungsprozess ist einer der Trends im Gebiet der Felsmechanik. Sie ist zugleich ein sehr wichtiges Forschungsprojekt u.a. fuer geotechnische Langzeitstabilitaetsanalyse, Langzeitsicherheit eines Endlagers, Erdwaerme- und Erdoelfoerderung. Dieser Aufsatz stellt die neusten Entwicklungen in den folgenden Teilgebieten zusammen: Untersuchungsmethoden, Laborversuchsergebnisse der Mikromechanik, der Computer-Tomographie und der akustischen Emission, zeitabhaengige Fraktaleigenschaften, Modelle fuer die Nervendynamik sowie Modelle fuer chemie-induzierte Schaedigungen. Zum Schluss werden kuenftige Forschungsschwerpunkte bzw. -richtungen diskutiert.

Resume

L'etude du processus de la localisation de l'endommagement du à l'erosion chimique est un thème d'actualite pour la mecanique des roches. Elle est egalement un sujet de recherche d'importance dans l'evaluation de la stabilite à long terme des ouvrages rocheux, l'analyse du system de stockage des dechets nucleaires et l'evaluation de son comportement, l'exploitation de l'energie thermique et petrolifère, etc. Cet article presente le developpement actuel dans ce domaine, incluant la methodologie d'etude sur le processus de la localisation de l'endommagement dû à l'erosion chimique, l'analyse des essais mecaniques avec l'observation microscopique, du balayage en temps reel (CT), et de l'emission acoustique. On aborde ainsi modèle des caracteristiques fractural du temps, le modèle de la mecanique dynamique neural, ainsi que la loi de comportement d'endommagement dû à l'effet chimique. Enfin, les perspectives relatives à ces etudes sont presentees et discutees.

Introduction

Study of nonlinear damage localization process of rocks under water chemical corrosion is very important in estimating long term stability of rock engineering, design of nuclear waste repository and its performance estimation, geothermal and petroleum development. Rock engineering is almost existent in underground/surface water environment. Ionic concentration and pH values in water solution may change strength of rock/rockmass or surface energy needed due to chemical reaction for cracking and its propagation. The experimental study has shown that when the x potential is zero the tensile strength of rock will reduce to minimum (Seto et al. 1998:13). This can be used to increase cracking of rock/rock mass by adding some special chemical solution to make zero × potential of drilling solution. In fact, deformation, damage, and fracturing of rock/rockmass under water chemical corrosion is a nonlinear localization process.

This paper reports research progress of the topic conducted by the authors' research group. The results of meso-mechanical experiment, real-time CT scan test and acoustic emission test to study nonlinear damage localization process of rocks under water chemical corrosion are introduced briefly in the first time.

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