Crosslinked xanthan gum biopolymer-based soil treatment (BPST) as a new ground improvement material to mitigate seismic liquefaction of loose sand

Abstract

In geotechnical engineering practice, several seismic liquefaction countermeasures have been suggested to mitigate the damage scale induced by earthquakes. Cement-induced ground improvement is the common preventative measure, where ground solidification mainly involves grout material injection into the ground (e.g., depth of 10 to 20 m). However, cement injection has environmental concerns (e.g. ground water pollution) and is ineffective in terms of seismic wave attenuation. Recently, biopolymer-based soil treatment (BPST) has been actively implemented in geotechnical engineering practices as an environmentally friendly approach. In this study, an enhanced BPST material (Cr³⁺-induced cross-linked xanthan gum) has been introduced to improve the seismic resistance of liquefiable loose sand. A cyclic direct simple shear apparatus was used to assess the cyclic stress ratio (CSR) and cyclic resistance ration (CRR) of clean and Cr³⁺-xanthan gum – BPST sand samples. According to experimental findings, the BPST condition with Cr³⁺-xanthan gum has higher CRR values than the clean and sole xanthan gum-treated sand cases. The experimental findings and seismic ground response analysis support the effectiveness of Cr³⁺-xanthan gum-BPST as a countermeasure to reduce the seismic risk of loose liquefiable sandy grounds.