Working Group on Sliding Safety of Existing Gravity Dams
Co-ordinator: Giovanni Ruggeri (Italy)
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Sliding Safety of Existing Gravity Dams - Final Report
Giovanni Ruggeri, Chairman of the European Working Group
SYNOPSIS. The European Working Group on “Sliding safety of existing gravity dams” started its activities in 2001 to examine the problem of the safety re-assessment against sliding forexisting gravity dams. The attention of the Group was concentrated on conventional concrete gravity dams, in static loading conditions. This Final report illustrates the results of the activities carried out by the Group. FOREWORD The European Working Group on “Sliding safety of existing gravity dams” is composed by the following members, from 9 Countries: − Giovanni Ruggeri Italy (Chairman) − RitaPellegrini Italy Moises Rubin de Celix Spain − − Morten Berntsen Norway Paul Royet France − − Volker Bettzieche Germany − Walter Amberg Switzerland Anders Gustaffsson Sweden − − Tony Morison United Kingdom Gerald Zenz Austria − This Final Report illustrates the results of the activities carried out by the Working Group. It is composed of the following sections: • Regulatory Rules and/or “NormalPractice” Information about Regulatory Rules, Guidelines or Normal Practice adopted in different Countries for the sliding safety assessment were collected and examined. • Safety assessment using site specific data Standard approaches may not fit well to existing dams, and safety reassessments taking into account the peculiar characteristic of the dam under examination are called for.
2SLIDING SAFETY OF EXISTING GRAVITY DAMS
• Significant experimental experiences The Group decided to review significant studies relevant to experimental evidences, highlighting the findings judged of main interest. • Techniques for the safety assessment A summary of available numerical methods for the sliding safety assessment was prepared, highlighting capabilities and limits of the differentmethods, referring to both well-consolidated traditional methods and more recent methods able to study the dam response from service conditions to limiting states. • Three-dimensional effects The conclusion given by a 2D analysis of a single monolith is subject to caution if 3D load sharing mechanisms can be mobilised across adjacent monoliths. TABLE OF CONTENTS This Final Report is composed of fivechapters. The Table of Contents of is the following: INTRODUCTION 1. REGULATORY RULES – GUIDELINES - COMMON PRACTICE 2. SAFETY ASSESSMENT USING SITE SPEFIC DATA 2.1 Geometrical features 2.2 External loads 2.3 Uplift pressures 2.4 Strength parameters 2.5 Three-dimensional effects 2.6 Bibliographic References 3. SIGNIFICANT EXPERIMENTAL EXPERIENCES 3.1 Examined studies 3.2 Tensile strength 3.2.1Concrete lift joints 3.2.2 Concrete-to-rock contact surface 3.3 Shear strength 3.3.1 Concrete lift joints 3.3.2 Concrete-to-rock contact surface 3.4 Remarks / Comments 3.4.1 Concrete lift joints 3.4.2 Concrete-to-rock contact surface 3.5 Bibliographic References 4. TECHNIQUES FOR THE SAFETY ASSESSMENT 4.1 Limit equilibrium approach 4.1.1 Hoek -Brown’s strength criterion 4.1.2 Burton’s strength...