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Journal of Engineering
Volume 2017 (2017), Article ID 4723017, 16 pages
https://doi.org/10.1155/2017/4723017
Research Article

Elastoplastic Modelling of an In Situ Concrete Spalling Experiment Using the Ottosen Failure Criterion

Aalto University, Rakentajanaukio 4 A, 02150 Espoo, Finland

Correspondence should be addressed to Lauri Kalle Tapio Uotinen; if.otlaa@nenitou.irual

Received 3 November 2016; Revised 26 December 2016; Accepted 27 December 2016; Published 31 January 2017

Academic Editor: İlker Bekir Topçu

Copyright © 2017 Lauri Kalle Tapio Uotinen and Topias Kalle Aleksi Siren. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

An in situ concrete spalling experiment will be carried out in the ONKALO rock characterization facility. The purpose is to establish the failure strength of a thin concrete liner on prestressed rock surface, when the stress states in both rock and concrete are increased by heating. A cylindrical hole 1.5 m in diameter and 7.2 m in depth is reinforced with a 40 mm thin concrete liner from level −3 m down. Eight 6 m long 4 kW electrical heaters are installed around the hole 1 m away. The experiment setup is described and results from predictive numerical modelling are shown. Elastoplastic modelling using the Ottosen failure criterion predicts damage initiation on week 5 and the concrete ultimate strain limit of 0.0035 is exceeded on week 10. The support pressure generated by the liner is 3.2 MPa and the tangential stress of rock is reduced by −33%. In 2D fracture mechanical simulations, the support pressure is 3 MPa and small localized damage occurs after week 3 and damage process slowly continues during week 9 of the heating period. In conclusion, external heating is a potent way of inducing damage and thin concrete liner significantly reduces the amount of damage.