期刊
INTERNATIONAL JOURNAL OF ROCK MECHANICS AND MINING SCIENCES
卷 140, 期 -, 页码 -出版社
PERGAMON-ELSEVIER SCIENCE LTD
DOI: 10.1016/j.ijrmms.2021.104642
关键词
Freeze-thaw weathering process; Rock strength deterioration; Compaction stress and strain; Statistical damage model; Constitutive model for rocks subjected to freeze-thaw weathering process
资金
- National Natural Science Foundation of China [51774323]
- Natural Science Foundation of Hunan Province [2020JJ4704]
- Fundamental Research Funds for the Central Universities of Central South University [2017zzts793]
The study investigates the stress-strain relationships of rocks subjected to different numbers of freeze-thaw cycles, revealing that with increasing cycles, the rock's strength decreases while strain increases. A new piecewise constitutive model is proposed, based on the characteristics of compaction and post-compaction stages of the stress-strain curve, which proves to be more effective in describing the stress-strain behavior of rocks with freeze-thaw damages compared to the reference model.
The recurrence of freeze-thaw processes induced by day-night and seasonal temperature changes is one of the most important reasons for damage and instability of rock engineering structures in cold regions. The study of the constitutive relationship and the damage degradation of rocks subjected to freeze-thaw weathering process is therefore of critical scientific importance to solving the stability problem of rock excavations in these regions. In this work, the stress-strain relationships of rocks subjected to different number of freeze-thaw weathering cycles were investigated in details. Experimental results show that as the number of freeze-thaw cycles increases, the compaction stage of the stress-strain curve becomes longer with more pronounced nonlinear features, while the uniaxial compressive strength, full compaction stress, tangent deformation modulus and initial deformation modulus all decrease, but the peak strain and full compaction strain all increase. A new piecewise constitutive model based on the characteristics of compaction and post-compaction stages of the stress-strain curve was proposed using a statistical compaction model in combination with the conventional statistical damage mechanics model with the strain equivalence hypothesis. Compared with the reference model, the proposed constitutive model has been demonstrated to be much more effective in describing the stress-strain behaviour of rocks having freeze-thaw damages, particularly when the number of freeze-thaw weathering cycles is significant. For all the experimental cases presented in this work, the coefficients of determination, R2, based on the proposed model are always greater than 0.93, while those of the reference model never exceed 0.85. In addition to, the model parameters have been shown to have clear physical meanings closely related to the characteristics of the measured stress-strain curve.
作者
我是这篇论文的作者
点击您的名字以认领此论文并将其添加到您的个人资料中。
推荐
暂无数据