EXPERIMENTAL AND NUMERICAL MODELING ON LIQUEFACTION RESISTANCE OF FIBER REINFORCED SAND

Sand liquefaction is one of main reasons leading to severe earthquake disasters. In this study,liquefaction resistance of sand reinforced by natural fiber under cyclic loading is discussed. A series of cyclic triaxial tests is carried out on reinforced sand specimens with different fiber contents under undrained conditions. The influence of cyclic shear strain amplitude and fiber content on liquefaction resistance of saturated sand is studied. Furthermore,a two-dimensional finite element numerical model for simulating finished cyclic triaxial test is established. The parameter calibration of reinforced sand with different fiber contents is performed. The results show that:(1)Increasing the amplitude of cyclic shear strain can promote the accumulation of excess pore pressure,which can speed up the reduction of slope of hysteresis loops and mean effective stress. (2)The presence of fiber can mitigate the accumulation of excess pore pressure,and liquefaction resistance of reinforced sand is significantly improved with increase of fiber content. (3)Calibrated constitutive model parameters can be reliably used to simulate liquefaction response of fiber reinforced sand. The results provide a valuable reference for liquefaction resistance of saturated sand and the numerical modeling of fiber reinforced sand.