چكيده به لاتين
Abstract:
Soil-cement columns have been implemented as a ground improvement technique for liquefaction mitigation throughout the years. However, more investigation is still needed to understand the reinforcement mechanism of soil-cement columns in liquefiable sand. This study presents three-dimensional nonlinear finite element simulation of soil-cement columns in a liquefiable sand layer using OpenSees platform. Results from a centrifuge experiment conducted at the Network for Earthquake Engineering Simulation (NEES) at the University of California-Davis are used to verify the numerical model .A good agreement between the experimental and executed numerical results is achieved and the overall site stiffening effect of soil-cement columns is evaluated, then parametric studies are performed to investigate the effect of parameters like length and diameter of the columns, thickness and relative density of liquefiable sand layer, shear modulus ratio for soil-cement columns and using fixed-type columns. The results of numerical analysis indicated that soil-cement columns were not effective in liquefaction mitigation. Furthermore, the effectiveness of these columns is not improved by increasing the column’s length and diameter, but the length of the columns must be extended beneath the liquefiable soil layer in order to control the settlement of overlying structure even after liquefaction. The results also indicated that the thickness of liquefiable soil layer plays an important role in liquefaction occurrence and volumetric strains.
Keywords: liquefaction, ground improvement, Soil-cement column, finite element
