基于粒度熵概念的贝壳砂颗粒破碎特性描述

对取自福建莆田湄洲湾海域的贝壳砂进行了不同围压、不同相对密度下的三轴排水剪切试验,同时考虑了尺寸效应的影响。依据试样试验前后粒径分布资料,在统计熵概念基础上提出颗粒破碎粒度熵模型对其破碎率进行了度量,并与Hardin颗粒破碎模型进行了比较,结果表明：贝壳砂颗粒破碎率与围压、相对密度及试样尺寸均有关系,在相同试验条件下,贝壳砂颗粒破碎程度随着试样尺寸的增加而增大,随着围压的增加而增大；当相对密度较低时,颗粒破碎率呈增大趋势；相对密度增加到较高值时,颗粒破碎程度减弱；贝壳砂三轴压缩前后的级配曲线均可以通过粒度熵模型参数表征,其中相对基础熵参数（NB）较好地反映了颗粒破碎程度大小,破碎率愈高,NB值愈小,NB与Hardin破碎率存在显着的线性关系。贝壳砂颗粒破碎粒度熵参数能较好地描述其颗粒破碎行为,为岩土介质材料的颗粒破碎分析提供了一个新的量化指标。

Characterization of particle breakage with grading entropy on shell sand

Laboratory triaxial shear tests on shell sand taken from Meizhou Bay of Putian, Fujian are presented under different confining pressures, relative densities and sample sizes. A grading entropy model is proposed to measure the particle breakage degree after triaxial compression based on the statistical entropy concept with dataset of particle size distributions. This methodology is also compared with Hardin particle breakage model. It is shown that the quantity of particle breakage of shell sand is affected by the confining pressure, relative density and the sample size. With the increase of the confining pressure and sample size, the quantity of particle breakage of shell sand increases under the same experimental conditions. When the relative density is low, the quantity of particle breakage tends to increase. While the relative density reaches a higher value, the particle breakage is weakened. The particle size distributions of shell sand before and after triaxial compression can be characterized by the grading entropy parameters, in which the relative base entropy parameter (NB) reflects the degree of particle breakage. The higher degree of particle breakage, the lower value of NB. There is a significant linear relationship between NB and Hardin's index. The behavior of particle crushing of shell sand can be greatly described by the grading entropy parameters, which may be a useful index for the quantitative analysis of the particle breakage of geotechnical materials.