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BULLETIN OF THE CHINESE CERAMIC SOCIETY ›› 2026, Vol. 45 ›› Issue (2): 712-724.DOI: 10.16552/j.cnki.issn1001-1625.2025.0773

• Road Materials • Previous Articles     Next Articles

Characteristics of Deformation and Energy Evolution of Roadbed Medium-Grained Sandstone under Differential Fatigue Loading

LIU Gaoxi1(), WU Yunfeng2(), LIU Yongliang3, LIU Yong2   

  1. 1. School of Intelligent Construction and Design,Henan Technical Institute,Zhengzhou 450042,China
    2. School of Resources and Safety Engineering,University of Science and Technology Beijing,Beijing 100083,China
    3. School of Civil Engineering,Henan University of Technology,Zhengzhou 450001,China
  • Received:2025-08-01 Revised:2025-10-15 Online:2026-02-20 Published:2026-03-09
  • Contact: WU Yunfeng

Abstract:

In order to reveal the mechanical response mechanism of medium-grained sandstone under differential fatigue load, this paper studied the deformation characteristics and energy evolution law of sandstone under three loading modes (slow loading and rapid unloading, constant speed loading and unloading, rapid loading and slow unloading) through laboratory tests. The dynamic changes of peak strain, residual strain and energy dissipation of the samples were analyzed by MTS 322 rock mechanics test system. The results show that under varying loading modes, the strain exhibited by sandstone remains consistent, with the residual strain approximating the deformation discrepancy between successive cyclic stages. The peak strain is observed to be largest in the slow and fast unloading mode, and smallest in the fast and slow unloading mode. Furthermore, the residual strain exhibits a logarithmic growth at the initial stage due to the compression and density of the internal defects, and increases linearly with the maximum cyclic stress in subsequent stages. The input energy and elastic energy increase stepwise with the number of cycles, and the dissipation energy increase rate is significantly higher in the slow-plus-slow unloading mode than in the other modes. The dissipation energy of the first cycle of a single cyclic stage is elevated, and the mean dissipation energy is exponentially associated with the maximum cyclic load. The dissipated energy ratio fluctuates and converges with the number of cycles, a phenomenon that is closely related to the internal damage inhomogeneity of material damage and the fluctuation of loading stress. The present study elucidates the influence mechanism of loading rate on the fatigue performance of sandstone, thereby providing a theoretical basis for the selection of road base layer materials and structural optimization.

Key words: medium-grained sandstone, differential fatigue loading, mechanical property, peak strain, residual strain, energy dissipation

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