Influence of surrounding rock temperature on fracture parameters of concrete for shotcrete use in the hot-dry tunnel environments

摘要

The objective of this study was to explore the influence of the surrounding rock temperature on fracture parameters of concrete. Four different surrounding rock temperatures were adopted and the three-point bending test on notched beams was conducted in this paper. Based on this test, the fracture energy, initial fracture toughness, unstable fracture toughness, and crack extension resistance of concrete were calculated via the double-K fracture model the KR curve crack propagation criterion. The results are summarized as follows: (1) The fracture energy of concrete beams increased first then decreased with the increment of the hot-dry environment temperature, and reached the peak at 60 degrees C. (2) The initial fracture toughness, unstable fracture toughness, and crack extension resistance of concrete decreased with the increment of the hot-dry temperature. (3) The length of the fracture process zone increased first then decreased with the increment of the effective crack length. (C) 2021 Elsevier Ltd. All rights reserved.