| Title |
Measurement of Friction Angle of Sand from Horizontal Stress and Torque Acting on Vane |
| Authors |
박성식(Park, Sung-Sik) ; 김동락(Kim, Dong-Rak) ; 이새벽(Lee, Sae-Byeok) |
| DOI |
https://doi.org/10.12652/Ksce.2018.38.1.0063 |
| Keywords |
베인전단시험;마찰각;모래;상재하중;수평응력 Vane shear test;Friction angle;Sand;Overburden pressure;Horizontal stress |
| Abstract |
In this study, the torque and horizontal stress acting on vane were measured and then used to determine a friction angle of sand. A dry Nakdong River sand was prepared for loose and dense conditions in a cell and then pressurized with 25, 50, 75 or 100 kPa from the surface of sand. A vane (5cm in diameter and 10cm in height) was rotated and the torque and horizontal stress were measured at real time. A maximum torque was 3.5-9.5Nm for loose sand and 7.4-17.6Nm for dense sand, respectively. The maximum torque increased as an overburden pressure increased. The maximum torque obtained at 14-20 degrees of vane rotation, which was not influenced by the initial alignment of earth pressure and vane blade. An initial horizontal stress ratio was 0.33-0.35 on the average. The horizontal stress increased initially and then decreased due to particle disturbance. A friction angle was calculated from real time varying horizontal stress and torque, which decreased with increasing overburden pressure. The friction angle of loose sand from vane shear test was similar to that of direct shear test but that of dense sand was overestimated. |