Zhang Zong-Tang, Liu An, Yu Si-Chun, Liu Shun-Kai, Fang Chuan-Feng, Liu Ze, Hu Wei
Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring, Hunan University of Science and Technology, Xiangtan, 411201, People's Republic of China.
School of Civil Engineering, Hunan University of Science and Technology, Xiangtan, 411201, People's Republic of China.
Sci Rep. 2025 Jan 13;15(1):1815. doi: 10.1038/s41598-025-85979-z.
The accumulation and discharge amount of coal gangue are substantial, occupying significant land resources over time. Utilizing coal gangue as subgrade filler can generate notable economic and social benefits. Coal gangue coarse-grained soil (CGSF) was used to conduct a series of large-scale vibration compaction tests and large-scale triaxial tests. The results indicate that the maximum dry density of CGSF initially increases and then decreases with the increase in fractal dimension. The stress-strain curves of the samples exhibit a distinct nonlinear growth pattern. Analysis of the compaction effect suggests that the compaction degree of CGSF should not be lower than 93%. As the confining pressure increases, the extent of failure strength improvement due to increased compaction decreases. Additionally, the failure strength of samples initially increases and then decreases with the increase in coarse particle content. A modified quadratic polynomial fractal model gradation equation was proposed to describe the gradation of samples after particle breakage. Based on this, a new quantitative index for particle breakage was established. Analysis of particle breakage in samples revealed that higher confining pressure and greater coarse particle content lead to increased particle breakage. The breakage exhibited a significant size effect, and the impact of particle gradation on sample breakage was greater than that of confining pressure. The stress-strain relationship of CGSF was analyzed by using a logarithmic constitutive model, and the correlation between model parameters and the newly derived particle breakage index was generated. A constitutive model incorporating particle breakage for CGSF was established, and its accuracy was validated.
煤矸石的堆积量和排放量巨大，长期占用大量土地资源。将煤矸石用作路基填料可产生显著的经济和社会效益。采用煤矸石粗粒土（CGSF）进行了一系列大型振动压实试验和大型三轴试验。结果表明，CGSF的最大干密度随分形维数的增加先增大后减小。试样的应力-应变曲线呈现出明显的非线性增长模式。压实效果分析表明，CGSF的压实度不应低于93%。随着围压的增加，压实度提高对破坏强度的提升程度减小。此外，试样的破坏强度随粗颗粒含量的增加先增大后减小。提出了修正二次多项式分形模型级配方程来描述颗粒破碎后试样的级配。在此基础上，建立了新的颗粒破碎定量指标。对试样颗粒破碎的分析表明，较高的围压和较大的粗颗粒含量会导致颗粒破碎增加。破碎呈现出显著的尺寸效应，颗粒级配对试样破碎的影响大于围压。采用对数本构模型分析了CGSF的应力-应变关系，并得出了模型参数与新推导的颗粒破碎指标之间的相关性。建立了考虑颗粒破碎的CGSF本构模型，并验证了其准确性。
