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Low Amplitude Fatigue Performance of Sandstone, Marble, and Granite under High Static Stress
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  • Kun Du,
  • Rui Su,
  • Jian Zhou,
  • Ming Tao,
  • Cheng Yang,
  • A. A. Momeni
Kun Du
Central South University
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Rui Su
Central South University
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Jian Zhou
Central South University
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Ming Tao
Central South University
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Cheng Yang
Central South University
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A. A. Momeni
Shahrood University of Technology
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Abstract

Fatigue tests under high static pre-stress loads can provide meaningful results to better understand the time-dependent failure characteristics of rock and rock-like materials. However, fatigue tests under high static pre-stress loads are rarely reported in precious literatures. In this study, the rock specimens were loaded with a high static pre-stress representing 70% and 80% of the UCS, and cyclic fatigue loads with a low amplitude (i.e., 5%, 7.5% and 10% of the UCS) were applied. The results demonstrate that the fatigue life decreased as the static pre-stress level or amplitude of fatigue loads increased for all rock types, and the high static pre-stress affected the fatigue life greatly when the static pre-stress was larger than the damage stress of rocks in uniaxial compression test. The accumulative fatigue damage exhibited three stages during the fatigue failure process: crack initiation, uniform velocity, and acceleration, and so the fatigue modulus showed an “S-type” change trend. The lateral strain and volumetric strain had a much higher sensitivity to the cyclic loading and could be used to predict fatigue failure characteristics, and it was found that volumetric strain “ε” _“v” = 0 is a threshold for microcracks coalescence and is an important value for estimating the fatigue life.

Peer review status:Published

Aug 2021Published in Geomechanics and Geophysics for Geo-Energy and Geo-Resources volume 7 issue 3. 10.1007/s40948-021-00266-1