Cone penetration model test of xanthan gum-treated sand based on particle image velocimetry technology and its bearing capacity prediction model

Commonly encountered problems, such as insufficient bearing capacity of the foundation and significant soil deformation, typically necessitate improvements to sandy soil. The excessive use of traditional soil improvement materials, such as cement and lime, causes irreversible damage to the ecological environment. As a sustainable soil reinforcement material, xanthan gum has broad application prospects with respect to its effects on the bearing capacity and deformation of sandy soil foundations. In this study, scanning electron microscope tests and cone penetration model tests based on particle image velocimetry technology were conducted to investigate the microstructure, mechanical behavior, and deformation characteristics around cones in sand treated with different xanthan gum rates. The test results show that the xanthan gum exerts cementation and filling effects between sand particles, enhanced the bearing capacity of sand. The displacement field around the cones in xanthan gum–treated sand during the penetration exhibits good symmetry. With increasing xanthan gum rate, the maximum displacement value and vertical influence range around the cone of xanthan gum-treated sand decrease, while the horizontal influence range increases. On the basis of the cone penetration test result, a predictive model for the vertical bearing capacity incorporating the xanthan gum rate is proposed using the Laboratoire Central des Ponts et Chaussées (LCPC) model. The research results can provide a scientific basis for using xanthan gum when designing and constructing sandy soil foundations.