Sostenimiento Minas

AFTES
RECOMMENDATIONS FOR THE

DESIGN OF SPRAYED CONCRETE
FOR UNDERGROUND SUPPORT
AFTES welcomes comments on this paper

Version 1 - Approved by Technical Committee 9 november 2000
Document presented by
Eric LECA (SCETAUROUTE) - Chairman Work Group 20
with the participation of :
Jean LAUNAY (GTM-DUMEZ) co-chairman - Philippe AUTUORI (BOUYGUES) Claude BASCOULERGUE (CAMPENON-BERNARD) -Alain BERNARDET (EEG - SIMECSOL) Daniel DUPUCH (SIKA) - Gilles GASPAR (SNCF) - Alain GUILLOUX (TERRASOL) - Jean PIRAUD (ANTEA) Michel PRE (SETEC) - Adrien SAITTA (CETU) - Laurent SAMAMA (SCETAUROUTE) - Joël SOLARD (RATP) Christophe VIBERT (COYNE & BELLIER) - Jacques WILLOCQ (LAFARGE)
Technical committee reviewers:
Guy COLOMBET (COYNE & BELLIER) - Pascal DUBOIS (CETU) Bernard GODINOT (GTM) andYann LEBLAIS (EEG - SIMECSOL)

PREFACE

T

his document presents the recommendations prepared by AFTES Work Group #20 for the design of sprayed concrete used in tunnels and underground openings. The proposed approach accounts for the different categories of sprayed concrete used in tunneling and underground works. The document presents the state-of-the-art and practice at the moment of itspublication. It shall be
revised in time to reflect the evolution of technologies and design concepts.
The following three types of sprayed concrete support are considered in this recommendation: protective layer, structural layer, and structural
ring. Cases where a structural layer is used in association with other support elements (mesh, ribs, bolts,…) are also addressed, but solely from
asprayed concrete design perspective; design procedures for support systems primarily consisting of bolts, whether these are associated
with a protective layer of shotcrete or not, will be dealt with in a forthcoming specific recommendation.
This document is based, amongst other things, on material published in literature or derived from experimental works on the characterization
of the mechanicalproperties of concrete, as well as in situ monitoring and design case histories. This material is documented in articles published in the present issue of the AFTES magazine, “Tunnels et Ouvrages Souterrains”.

CONTENTS
Pages

Pages

1 - INTRODUCTION - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 1.1 - THE THREE PRINCIPAL ACTION MODES OF SPRAYED
CONCRETE - - - - - - - - -- - - - - - - - - - - - - - - - - - - - - - - - - - 1.2 - PRESENTATION OF THE RECOMMANDATIONS - - - - - - - - -

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2 - THE THREE TYPES OF SPRAYED CONCRETE SUPPORT- - - 2.1 - TYPE 1 : SPRAYED CONCRETE AS A PROTECTIVE LAYER - 2.2 - TYPE 2 : SPRAYED CONCRETE AS A STRUCTURAL LAYER
ASSOCIATED TO REINFORCEMENT - - - - - - - - - - - - - - - - 2.3 - TYPE 3 : SPRAYED CONCRETE AS A STRUCTURAL RING -2.3.1 - Limitation of the ground’s elasto-plastic deformations- 2.3.2 - Confinement in grounds that cannot be bolted- - - - - - 2.3.3 - Confinement of swelling grounds (clays anhydrites) - - 2.3.4 - Repair of older tunnels- - - - - - - - - - - - - - - - - - - - - - - - -

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3 - RHEOLOGY OF SPRAYED CONCRETE - - - - - - - - - - - - - - - - 3.1 - SPRAYCONCRETE: REQUIRED COMPOSITION - - - - - - - - 3.1.1 - Aggregates - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3.1.2 - Cement- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3.1.3 - Water - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3.1.4 - Fibres - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3.1.5 - Admixtures -- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3.1.6 - Additives- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - 3.2 - REQUIRED MECHANICAL CHARACTERISTICS FOR THE
DIFFERENT TYPES OF SPRAYED CONCRETE - - - - - - - - - - 3.2.1 - Type 1 sprayed concrete (protective layer) - - - - - - - - - 3.2.2 - Type 2 sprayed concrete (structural layer) - - - - - - - - - -...