粒类料直剪试验强度尺寸效应及剪切带特性研究  

Size Effect of Shear Strength in Granular Materials and Characteristics of Shear Bands in Direct Shear Test

作　　者：张庆建[1] 王鹏程[1] 于磊 张富臣 ZHANG Qing-jian;WANG Peng-cheng;YU Lei;ZHANG Fu-chen(China Water Resources Beifang Investigation,Design and Research Co.,Ltd.,Tianjin 300222,China)

机构地区：[1]中水北方勘测设计研究有限责任公司,天津300222

出　　处：《海河水利》2023年第7期90-95,99,共7页Haihe Water Resources

摘　　要：中粗砾料地基抗剪强度指标多采用经验或通过大型直剪试验获取。为了探索不同粒径砾类料适合的剪力仪尺寸,将5种不同最大粒径的砾类料与4种尺寸剪力仪进行组合试验,以大型直剪试验结果为基准值,研究各组合试验强度尺寸效应和剪切带特征。试验结果表明,试样抗剪强度及指标参数均随径径比增加先减小后趋于稳定,试样最大粒径越大,强度尺寸效应越显著。同径径比下,随着法向应力增加,抗剪强度与基准值间差异逐渐增大,尤其以最大粒径较大者显著。最大粒径2~10mm试样可选用Φ150mm剪力仪,最大粒径10~20mm试样宜选用Φ250mm剪力仪,最大粒径20~40 mm试样宜选用Φ350 mm剪力仪。试样剪切带宽度与颗粒粒径成正比,与法向应力成反比。The shear strength index of medium-coarse gravel foundation is usually obtained by experience or large-scale direct shear test.In order to explore the suitable size of shear apparatus for gravel with different grain sizes,the combined tests of five gravel with different maximum grain sizes and four sizes of shear apparatus are carried out.Based on the results of large-scale direct shear tests,the size effect of strength and the characteristics of shear bands are studied.Test results show that the shear strength and parameters of the specimen decrease firstly and then stabilize with the increase of diameter ratio,and the larger the maximum grain size of the specimen,the more significant the size effect of strength.With the increase of normal stress,the difference between the shear strength and the reference value increases gradually,especially for the larger maximum grain size.Φ150 mm shear apparatus can be selected for specimen with the maximum grain size of 2 to 10 mm;Φ250 mm shear apparatus should be selected for specimen with the maximum grain size of 10 to 20 mm,andΦ350 mm shear apparatus should be selected for specimen with the maximum grain size of 20 to 40 mm.The width of shear band is proportional to the grain size and inversely proportional to the normal stress.

关 键 词：砾类料 直剪试验 抗剪强度 径径比 尺寸效应 剪切带 

分 类 号：TV223.1[水利工程—水工结构工程]