Experimental Study on the Minimum Required Specimen Width to Maximum Particle Size Ratio in Direct Shear Tests

CivilEng

Li Li¹  Akram Deiminiat¹  Feitao Zeng¹ 

[1] Research Institute on Mining and Environment, Department of Civil, Geological and Mining Engineering, Polytechnique Montreal, Montreal, QC H3T 1J4, Canada;

关键词: shear strength;    direct shear tests;    friction angle;    specimen size effect;    minimum required specimen sizes;    ASTM D3080/D3080M-11;   

DOI  :  10.3390/civileng3010005

来源: DOAJ

【 摘 要 】

Conducting laboratory direct shear tests on granular materials is a common practice in geotechnical engineering. This is usually done by following the ASTM D3080/D3080M-11 (hereafter named ASTM), which stipulates a minimum required value of 10 for specimen width (W) to the maximum particle size (d_max) ratio. Recently, a literature review performed by the authors showed that the minimum required W/d_max ratio given in the ASTM is not large enough to eliminate the specimen size effect (SSE). The minimum required W/d_max ratio of ASTM needs to be revised. In this study, a critical analysis is first made on existing data in order to identify the minimum required W/d_max ratio. The analysis shows that more experimental data obtained on specimens having W/d_max ratios between 10 and 50 are particularly necessary. To complete this need, a series of direct shear tests were performed on specimens having different d_max by using three shear boxes of different dimensions. The results show once again that the minimum required W/d_max ratio of 10, defined in the ASTM, is not large enough to eliminate the SSE. Further analysis on these and existing experimental results indicates that the minimum required W/d_max ratio to remove the SSE of friction angles is about 60. These results along with the limitations of this study are discussed.

【 授权许可】

Unknown