工程科学学报2018，Vol.40Issue(3)：302-312,11.DOI:10.13374/j.issn2095-9389.2018.03.006
混合颗粒体光弹力链定量提取方法
A quantitative extraction method of force chains for composite particles in a photoelastic experiment
摘要
Abstract
In geotechnical and mining engineering, numerous particle matters are involved in scientific and technical problems. Recognition and quantification of the structure and distribution of force chain networks using photoelastic experiments, for instance, are significantly important in understanding the internal mechanism of mesoscopic mechanics and studying the macroscopic mechanical behavior. Based on the algorithm of the mean square value of color gradient ( G2 ) , the correlations of G2 with the contact force ( F) of different sizes of round and square particles were established and combined with digital image processing technology. A method was pro-posed for identifying particles in images and distinguishing square particles from round ones, and force chain structures and force chain distributions were obtained in photoelastic images. Using fully mechanized caving mining as an example, the proposed method was verified, and it elaborated the formation and characterization of mining-induced stress in a top-coal caving mining face. The study shows that F monotonically increases with increased G2 , and larger particle sizes correspond to a faster growth of F. The contact forces of singular particle distribute primarily between 0. 5 and 1. 5 times average contact force. Also, the average contact forces in square particles and φ12 mm circular particles are higher and mainly occur in strong force chains, whereas average contact forces inφ10 mm andφ8 mm circular particles are lower and primarily occur in weak force chains. In top-coal caving mining, force chains in top-coal and overburden strata are mainly displayed in tree-like forms. Strong force chains, which extend in a vertical direction, transmit majority overburden loads, whereas lateral-developed weak force chains play a role in supporting strong force chains. In the vicinity of the top-coal out-lets, because of the lateral movement of particles toward the mined area, the weak force chains in top coal disappear, resulting in the strong force chains becoming weaker or completely disappearing.关键词
光弹试验/混合颗粒/力链/数字图像处理/综放开采Key words
photoelastic experiment/composite particles/force chain/digital image processing/fully mechanized top coal caving mining分类
数理科学引用本文复制引用
李飞,杨柳,王金安,王超..混合颗粒体光弹力链定量提取方法[J].工程科学学报,2018,40(3):302-312,11.基金项目
国家自然科学基金资助项目(U13612034) （U13612034）
中国博士后基金资助项目(2017M610047) （2017M610047）
中央高校基本科研业务费专项基金资助项目(FRF-TP-16-075A1) （FRF-TP-16-075A1）
