فاطمه قائمي

Soil-Cement columns are a common method of soil improvement used to against soil liquefaction and reducing liquefaction-induced settlements. In this paper, an extensive parametric study is carried out in order to examine the effectiveness of Soil-Cement columns in liquefaction mitigation using a nonlinear three-dimensional (3D) finite-element (FE) numerical modeling using the OpenSees program. The validity of the model was eva‎luated by comparing the results obtained from the numerical model with the results from an experimental centrifuge study. Then Parametric analyses are performed for different values of area replacement ratios, shear modulus ratios, improvement depth, thickness and position of liquefiable soil, the thickness and the permeability of the Geotextiles. Additional, the effect of using Geotextiles on the performance of soil-cement columns has also been investigated. The results of the parametric analyses are eva‎luated by examining peak surface acceleration, excess pore water pressure ratio and surface settlements. results have shown that increase the length, shear modulus ratios and area replacement ratios up to 30% of the columns were not significant effective in liquefaction mitigation. Besides, the responses of the saturated stratified sand strata are not only dependent on the thickness of the liquefiable layer but are also highly influenced by its position. results also indicated that the encasing the colums with geotextiles reduces the excess water pressure ratios, settlement and increases the liquefaction resistance. also In this paper, The the shear reinforcement mechanism of Soil Cement columns investigated by focusing on the shear strain and shear stress distribution between liquefiable soil an columns and It was found that the shear reinforcement mechanisms of columns was not effective in reducing cyclic stress ratios in the treated soil, such that the shear strain compatibility assumption can be significantly unconservative.

روانگرايي , بهسازي , ستون خاك-سيمان , مدلسازي عددي , اپنسيس , سازگاري كرنش برشي

liquefaction , improvement , soil-cement columns , Numerical modeling , OpenSees , Shear strain compatibility

Fatemeh Ghaemi

Dr Mohammad Hassan Baziar_Dr Alireza Saeedi Azizkandi