Fatigue failure characteristics and energy evolution mechanism of fractured rock under graded cyclic loading
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Affiliation:

1.School of Architecture and Civil Engineering, Shenyang University of Technology, Shenyang 110870, P. R. China;2.Fifth Engineering Co., Ltd., China Railway 19th Bureau Group, Dalian 116100, Liaoning, P. R. China

Clc Number:

TU458

Fund Project:

National Natural Science Foundation of China (Nos. 51974187, 51774066); Liaoning Natural Science Foundation (No. 2019-MS-242); Liaoning Provincial Education on Department Focuses on Tackling Key Problems (No. LZGD2020004); China Postdoctoral Science Foundation (No. 2018M630293); Key Scientific Research Foundation Project of Shenyang University of Technology (No. ZDZRGD2020005).

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    Abstract:

    The crack propagation mode, fatigue deformation characteristics and energy evolution pattern of cracked rock under graded cyclic loading are of great significance to the safe construction and operation of underground engineering. Conventional splitting test, graded cyclic load test and non-contact deformation measurement test were carried out considering the crack angle, crack number and distribution. The failure characteristics and dynamic elastic modulus were analyzed, and the relationship between axial irreversible deformation and fatigue life was studied. From the perspective of energy, the total absorbed energy, released strain energy and dissipated energy in the failure process were calculated, and the relationship between energy evolution and the response of crack propagation mode was analyzed. The results show that :(1) The fatigue deformation of rock can be divided into the initial deformation stage, stable stage and the accelerated failure stage, and the hysteretic loop curve presents the characteristics of “thin-dense-thinness”. The dynamic elastic modulus of every 200 cycles is analyzed and that of the second loading stage is strengthened. In addition, the dynamic elastic modulus decreases after the third loading stage. (2) The total absorbed energy, dissipated energy and elastic energy all showed an upward trend. The total absorbed energy increased slowly, and the growth rate gradually slowed down with the increase of cycles. The dissipated energy increases rapidly after entering the failure stage, but the elastic strain energy does not change obviously, and the dissipated energy is more in the middle dip angle. (3) During failure process, wing cracks and inclined secondary cracks are generated, and the interaction and merger of the cracks result in continuous plastic strain accumulation and small particle debris, which is different from the brittle failure mechanism under static load.

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王军祥,赵会敏,郭连军,李林,徐晨晖,孙港.分级循环荷载下裂隙岩石疲劳破坏特性与能量演化机制[J].土木与环境工程学报(中英文),2024,46(3):103~114

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History
  • Received:December 04,2021
  • Revised:
  • Adopted:
  • Online: May 20,2024
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