Study on deterioration mechanism of mechanical property and microscale structure in Xanthan gum reinforced soil under dry and wet cycle based on CT scanning technology

The dry-wet cycle has an important effect on the engineering properties of rock and soil. In this paper, CT scanning technology and mechanical properties testing methods were used to study the deterioration mechanism of clay reinforced with different contents of xanthan gum (0%, 0.5%, and 1.5%) under different times of dry-wet cycles (0, 1, 4, 8, 12). The main conclusions were as follows: (1) Xanthan gum can effectively improve the compressive strength and dry-wetting resistance of the soil. With the increase of xanthan gum content, the strength loss after wet-drying cycles decreased gradually. When the times of cycles increased from 0 to 4, the compressive strength of the soil with xanthan gum content of 0%, 0.5% and 1.5% decreased by 42.75%, 17.2% and 14.04%, respectively. When the time of cycle was 0 and 1, the elastic modulus showed a decreasing trend with the increase of xanthan gum content. (2) There is an exponentially decreasing relationship between the compressive strength of the reinforced soil and the times of dry-wetting cycles. When the times of cycle reached 4, the change of the compressive strength begins to slow down, and the elastic modulus of the samples all showed a significant decline, and with the further increase of the times of cycle, the elastic modulus fluctuated in a small range. (3) With the increase in the time of dry-wetting cycles, the porosity of Xanthan gum reinforced soil showed a trend of increasing first and then decreasing. When the times of cycle were less than 8, the