Abstract: The mud cake formation on shield cutterhead in clay strata severely impacts tunnelling efficiency. Traditional single-component soil conditioner faces limitations in adhesion inhibition effectiveness and unclear mechanisms. To resolve these limitations, this study develops a synergistic soil conditioning approach integrating foam agents and dispersants. Comprehensive experiments were conducted to assess adhesion reduction performance, supported by quantitative analyses of liquid-plastic limits, zeta potential, and interparticle repulsion energy to clarify the fundamental mechanisms. Results reveal that under optimal synergistic parameters (20% foam injection ratio with 0.1%-0.2% dispersant dosage), the combined additives achieve superior adhesion mitigation. The conditioners reduce the liquid-plastic limits and increase the negative charge of the soil, causing the Zeta potential to decrease with increasing conditioner dosage. Moreover, dispersants synergize with foam lubrication to intensify interparticle electrostatic repulsion energy, thereby effectively suppressing clay particle agglomeration and adhesion on cutterhead surface.