Tri-axial shear behavior of xanthan gum biopolymer-treated sand

Abstract

Recently, soil strengthening using gel-type biopolymers have been attempted by many researchers. However, most previous studies have been conducted by focusing on feasibility of biopolymers as a new soil binder with lack of in situ considerations (e.g., confinement and strain-stress related variation). This study aims to investigate the shear behavior of xanthan gum-treated sand under different in situ confinement conditions. Laboratory tri-axial test is performed under three different confinement conditions (σ3=50 kPa, 100 kPa, 200 kPa) with different xanthan gum biopolymer contents (mbp/ms=0.5%, 1.0%, 2.0%). It is revealed that high shear strength is developed when the biopolymer film matrix is established within the pore space when the biopolymer is thoroughly dried in the laboratory (oven). The strengthening effect by biopolymer film is substantial although its enhancement is varied according to xanthan gum contents and confinement conditions.