Evaluation of Similitude Laws for Dissipation Velocity of Excess Pore Pressure after Liquefaction using Impulse Load Tests

충격하중시험을 이용한 액상화 후 과잉간극수압 소산속도의 상사비 연구

The purpose of this study is to find out the similitude laws for dissipation velocity of excess pore pressure after liquefaction according to magnitude of input accelerations and height of model soils from the results of impulse load tests. In impulse load tests, model soils were constructed to the height of 25cm, 50cm, and 100cm in acrylic tubes whose inside diameters were 19cm and 38cm respectively, and impulse loads were applied at the bottom of each model soil to liquefy the entire model soil. Excess pore pressure distribution by depth and settlement of soil surface were measured in each test. Dissipation curves of excess pore pressure measured in each tests were simulated by solidification theory, and dissipation velocities of excess pore pressure were determined from the slope of simulated dissipation curves. From the results of impulse load tests, dissipation velocity of excess pore pressure was not affected by magnitude of input acceleration, and from this fact, dissipation process was proved to be different from dynamic phenomenon. However, dissipation velocity of excess pore pressure increased as height of model soil increased and showed little difference as diameter of model soil increased. Therefore, the similitude law for dissipation velocity could be expressed by the similitude law for model height to 0.2 without regard to the diameter of model soil.