钙质砂颗粒破碎演化规律和预测模型研究  

Study on evolution law and prediction model of calcareous sand particle fragmentation

作　　者：杨星 旷杜敏 粟劲苍[1,2] YANG Xing;KUANG Dumin;SU Jincang(College of Civil Engineering,Xiangtan University,Xiangtan 411105,China;School of Materials Science and Engineering,Xiangtan University,Xiangtan 411105,China)

机构地区：[1]湘潭大学土木工程学院,湖南湘潭411105 [2]湘潭大学材料科学与工程学院,湖南湘潭411105

出　　处：《湘潭大学学报(自然科学版)》2025年第2期108-120,共13页Journal of Xiangtan University(Natural Science Edition)

基　　金：湖南省自然科学基金(2022JJ40440);湖南省教育厅优秀青年基金(22B0151)。

摘　　要：颗粒破碎会引起颗粒级配发生变化,从而对其物理力学性质产生影响.为定量描述侧限压缩作用下混合粒组钙质砂颗粒破碎的演化规律,基于分形分布理论,采用不同初始孔隙比和不同初始分形维数的混合粒组钙质砂,开展了不同终止轴向应变的侧限压缩试验.根据颗粒破碎的级配演化情况,建立了能综合考虑混合粒组中各单粒径组的级配演化模型.试验结果表明:钙质砂试样的压缩过程可依次表述为颗粒的位置调整、颗粒破碎和颗粒重排、颗粒密实化,在颗粒排列相对更为疏松的情况下,即初始孔隙比越大或初始分形维数越小,屈服应力更小.颗粒的相对破碎率随着轴向应变的增大而增大,映射其线性关系的斜率与初始孔隙比和初始分形维数密切相关,进而推导出能描述4个变量之间关系的表达式,其中波动范围最大的参数随初始孔隙比的增大而增大,随初始分形维数的增大而减小.在此基础上,求解了能描述混合粒组钙质砂颗粒破碎级配演化规律的模型,与试验对比分析发现模型预测效果良好,为研究钙质砂的颗粒破碎问题提供了新思路.Particle crushing causes changes in particle gradation,which has an effect on their physical and mechanical properties.In order to quantitatively characterize the evolution law of particle fragmentation of calcareous sand of mixed grain group under confined compression,based on the fractal distribution theory,confined compression tests with different termination axial strains were carried out using calcareous sands of mixed grain group with different initial porosity ratios and different initial fractal dimensions.Based on the gradation evolution of particle crushing,a gradation evolution model that can comprehensively consider each single particle size group in the mixed particle group was established.The test results show that the compression process of calcareous sand specimens can be expressed sequentially as the positional adjustment of particles,particle fragmentation and particle rearrangement,and particle densification,and that in the case of a relatively more sparse particle arrangement,the larger the initial porosity ratio or the smaller the initial fractal dimension,the lower the yield stress.The relative fragmentation rate of the particles increases with increasing axial strain,and the slope of the mapping of its linear relationship is closely related to the initial porosity and the initial fractal dimension,from which expressions can be derived to describe the relationship between the four variables,with the parameter that fluctuates in the largest range increasing with increasing initial porosity and decreasing with increasing initial fractal dimension.On this basis,a model describing the evolution of particle crushing gradation of calcareous sand with mixed grain group was solved,and the comparison and analysis with the experiment showed that the model predicted well,which provided a new way of thinking for the study of particle crushing problem of calcareous sand.

关 键 词：钙质砂 侧限压缩试验 分形分布理论 颗粒破碎 级配演化规律 

分 类 号：TU43[建筑科学—岩土工程]