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Titolo:
EFFECTS OF HEAT ON THE MECHANICAL-BEHAVIO R OF CONCRETE LININGS FOR TUNNELS
Autore:
AGGOUN S; TORRENTI JM; PROST J; LEGRAND M;
Indirizzi:
LAB REG PONTS & CHAUSSEES,OUVRAGE ART GRP LYON FRANCE LAB CENT PONTS & CHAUSSEES CELLULE MECAN & STRUCT,BETONS BETONS ARMES& PRECONTRAINTS SECT PARIS FRANCE DEPT TUNNELS & TRAVAUX SOUTERRAINS ANNECY FRANCE
Titolo Testata:
Materials and structures
fascicolo: 167, volume: 27, anno: 1994,
pagine: 138 - 147
SICI:
1359-5997(1994)27:167<138:EOHOTM>2.0.ZU;2-C
Fonte:
ISI
Lingua:
FRE
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
24
Recensione:
Indirizzi per estratti:
Citazione:
S. Aggoun et al., "EFFECTS OF HEAT ON THE MECHANICAL-BEHAVIO R OF CONCRETE LININGS FOR TUNNELS", Materials and structures, 27(167), 1994, pp. 138-147

Abstract

The use of an unreinforced sectional concrete lining in rock excavated tunnels presently appears to be technically and economically appropriate for ensuring good stability and effective operation. However, this type of structure suffers from systematic crack formation. In the absence of external loads, cracking in this type of lining is closely related to the physico-chemical characteristics of the material and to the environment in which this material is ageing. The phenomenon is worsened by conditions particular to tunnels, viz., on the one hand, the strains hindered by the surrounding ground, and on the other the pre-cast invert; also, the presence of geometric overbreaks can lead to variations in the lining thickness. The importance of the heat and hydration gradients resulting from the above phenomena is demonstrated by field tests. Numerical simulations based on laboratory tests let us assess the resulting stresses, (i) Practically unavoidable transverse crack formation can result from the effects of heat. The width of this type of crack and the frequency depend especially on the outer shape and on the proportion of cement in the concrete, (ii) Surface skin cracking can occur, resulting from the effects of hydration. Checks made in the tunnels investigated revealed the cracks expected from our computations. However, these results, in terms of thermal stresses, should notbe overestimated especially bearing in mind the numerical model currently used, which does not consider creep effects during the setting and initial hardening of the concrete.

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Documento generato il 28/03/20 alle ore 21:14:24