TY - JOUR
T1 - Evaluation of size and boundary effects in simple shear tests with distinct element modeling
AU - Chang, Wen Jong
AU - Phantachang, Thitibhorn
AU - Ieong, Wai Man
N1 - Funding Information:
This study was supported by the Ministry of Science and Technology, Taiwan, under grant NSC 100-2625-M-006-008-MY3, which is gratefully acknowledged. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the authors, and do not necessarily reflect the views of the Ministry of Science and Technology, Taiwan.
PY - 2016
Y1 - 2016
N2 - Because the direct simple shear (DSS) mode is recognized as the most representative failure condition along a sliding surface, a DSS testing system capable of testing large soil particles is useful to determine the strength parameters of gravelly soils. In DSS tests, the size and boundary effects are two crucial factors that affect the consistency of the test results. To evaluate the size and boundary effects in DSS conditions, numerical experiments using the distinct element method are performed to investigate the influences of specimen dimensions on the macroscopic stress-strain relationship and microscopic uniformity in terms of the specimen diameter (D), specimen height (H), and maximum particle size (dmax). The size effect is evaluated on the variations of stress-strain curves with the specimen dimensions and dmax. The boundary effect is assessed in terms of the spatial distribution of the particle displacement and contact force fields. The results show that: 1. the boundary effect can be reduced effectively when H/D decreases, 2. the difference in boundary effect is insignificant between Cambridge and Norwegian Geotechnical Institute types of simple shear configurations, and 3. there is a relatively consistent stress-strain relationship when H/dmax is no less than 7.
AB - Because the direct simple shear (DSS) mode is recognized as the most representative failure condition along a sliding surface, a DSS testing system capable of testing large soil particles is useful to determine the strength parameters of gravelly soils. In DSS tests, the size and boundary effects are two crucial factors that affect the consistency of the test results. To evaluate the size and boundary effects in DSS conditions, numerical experiments using the distinct element method are performed to investigate the influences of specimen dimensions on the macroscopic stress-strain relationship and microscopic uniformity in terms of the specimen diameter (D), specimen height (H), and maximum particle size (dmax). The size effect is evaluated on the variations of stress-strain curves with the specimen dimensions and dmax. The boundary effect is assessed in terms of the spatial distribution of the particle displacement and contact force fields. The results show that: 1. the boundary effect can be reduced effectively when H/D decreases, 2. the difference in boundary effect is insignificant between Cambridge and Norwegian Geotechnical Institute types of simple shear configurations, and 3. there is a relatively consistent stress-strain relationship when H/dmax is no less than 7.
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U2 - 10.6310/jog.2016.11(3).3
DO - 10.6310/jog.2016.11(3).3
M3 - Article
AN - SCOPUS:85010213484
SN - 1990-8326
VL - 11
SP - 133
EP - 142
JO - Journal of GeoEngineering
JF - Journal of GeoEngineering
IS - 3
ER -