NUMERICAL SIMULATION OF UNSATURATED LIQUEFACTION TEST USING VOLCANIC SOILS DAMAGED IN THE 2018 HOKKAIDO IBURI EASTERN EARTHQUAKE

Abstract

 In this paper, the numerical simulations were conducted in order to reproduce the tendency obtained in the unsatured liquefaction tests (cyclic tri-axial tests) using volcanic soils (Spfa-1 and En-a) damaged in the 2018 Hokkaido Iburi eastern earthquake. In the numerical simulations, the three-phase porous media theory was applied. However, the simulated results underestimated the unsaturated liquefaction resistance in unsaturated conditions, because the constitutive models used in the simulations were developed for describing the tendency of liquefaction characteristics for saturated soils. Therefore, the evolution rules focused on the change of void ratio were proposed for modifying the dilatancy characteristic of unsaturated soils. The simulated results using proposed method could successfully reproduce the tendency obtained in the tests using both soil.