Research on the Influence Mechanism of Foam Slurry Wall Formation

Incorporating foam into slurry can improve its wall-supporting performance. However, the wall formation mechanism of foam slurry under different conditions remains unclear. In this study, numerical simulations were conducted to investigate the influence of soil properties, slurry composition, and pressure gradient on the infiltration process and wall formation effectiveness of foam slurry, which was validated through laboratory experiments. The results indicate that the infiltration process of foam slurry in soil can be divided into three stages—infiltration, clogging, and membrane formation. The time required for slurry membrane formation increases linearly with increasing soil porosity and gradation parameter m, while it decreases with increasing gradation parameter b. An increase in the swelling ratio promotes faster membrane formation, whereas a higher foam content may reduce clogging efficiency. The time required for slurry membrane formation increases quadratically with the pressure gradient. The influence of various factors on the effectiveness of foam slurry wall formation are observed in the following order: soil properties > slurry composition > pressure gradient. When using foam slurry for wall formation, it is advisable to use a relatively high swelling ratio (>5%) and an appropriate foam concentration (approximately 10% to 20%) to improve the stability of the slurry wall.