Influence of test quantity on loose sand shearing strength parameters

Abstract

Investigation of the shear strength properties of Klaipėda sand by simple shear test is presented. The characteristic values of the angle of internal friction φk and the cohesion ck are obtained via the least squares method and various factors of influence are elucidated. The investigation reveals the test quantity to have a significant influence on the characteristic shear strength parameters for loose sand. The processed characteristic magnitude of the angle of internal friction varies within 16.14 0 (3 tests) and 27.02 0 (36 tests) bounds, that of the characteristic cohesion varies within - 74.18 kPa (3 tests) and 1.12 kPa (36 tests) bounds. The above mentioned shear strength properties confirm the linear Mohr-Coulomb strength criterion obtained via processing the test data. The same scatter of characteristic shear strength parameters variation is obtained when the peak shear stress are recorded for horizontal displacement magnitude of 5 mm. In this case the obtained characteristic angle of the internal friction varies within the bounds of 17.38 0 (3 tests) and 26.79 0 (36 tests), and that of characteristic cohesion within various within -68.82 kPa (3 tests) and 1.18 kPa (36 tests) bounds. The authors recommend performing at least 18 experimental tests in order to avoid high influence on statistical coefficient of confidence level tα and on the number of degrees of freedom k.