It is of great importance to prevent a leakage of hazardous substances from underground storage plants, because this certainly leads to a fatal disaster for human societies. Therefore, effective grouting system needs to be developed, which can inject cement grout into low-permeable rock masses. Authors have carried out a series of laboratory injection tests using a fracture model and field tests in low-permeable rock masses. In these tests, not only was the superiority of dynamic grouting confirmed, but also the relationship between grouting-efficiency and injection parameters was investigated. In this paper, the results of laboratory injection tests and field tests together with theoretical approaches to them are mentioned.

L'empêchement de la fuite des substances dangereuses des galeries de stockage est un traitement très important pour proteger la societe humaine contre la comtamination catastrophique. Par consequent, un procede d'injection efficace doit être mis au point, qui peut injecter du coulis de ciment dans le rocher ayant une permeabilite basse. Les auteurs ont effectue une serie d'essais d'injection en laboratoire en utilisant un modèle de rupture et d'essais sur le terrain dans le rocher ayant une permeabilite basse. Dans ces essais, etait non seulement la superiorite du l'injection dynamique confirmee, mais aussi le rapport entre l'efficacite de l'injection et les paramètres d'injection a ete etudie. Dans cet article, les resultats des essais d'injection en laboratoire et des essais sur le terrain ainsi que les methodes theoriques pour les essais sont mentionnes.

Es ist wichtig, Durchsickerns gefahrlicher Substanzen aus unterirdischen Lagerstellen zu verhindern, weil dies fuer die menschliche Gesellschaft unter Umstanden zu verheerenden Unfallen fuehren kann. Daher muß ein effizientes VerfugesSystem entwickelt werden, welches erlaubt den Mörtelschlamm in wenig durchlassige Felsenmassen einzuspritzen. Die Autoren haben eine Serie von Laboreinspritzungsversuchen mit einem Bruchmodell und Feldversuche an wenig durchlassigen Felsenmassen durchgefuehrt. Diese Versuche zeigten nicht nur die Überlegenheit des dynamischen Verfugens, sondern wurde dabei auch das Verhaltnis zwischen Verfugen und Leistungsfahigkeit sowie den Einspritzungparametern untersucht. In dieser Studie werden die Ergebnisse der Laboreinspritzungtests und die Feldversuche zusammen mit den entsprechenden theoretischen Ansatzen erlautert.

Introduction

The materials stored in underground rock storage facility have been gradually diversified as the time changes (e.g. high-pressure gas storage, high level radioactive waste repository, etc.). In order to store these materials, higher reliable storage function is required and permeability of rock masses around the cavern must be improved sufficiently. Therefore, it is important to develop the effective grouting technique for low-permeable rock masses. The authors have developed the dynamic grouting system, which is characterized by adding the oscillating pressure to a fixed underlying pressure (Date et al., 20021). Since oscillating pressure reduces flow resistance of suspension,

  1. the increase of flow rate and total grout take, and/or

  2. the adoption of stable suspension with low w/c ratio can be expected.

Due to such effects, a larger quantity of cement would be injected into fine fractures, which are difficult to seal sufficiently, than by the conventional static system.

In this study, several cases of laboratory and field tests have been carried out in order to confirm the effect of dynamic grouting. In these tests, the relationship between the effect of dynamic grouting and the injection parameters, type of grout material, w/c ratio of suspension, amplitude and frequency of oscillating pressure, is also investigated.

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