Abstract: In-situ stabilization of shallow silt layers can form an artificial hard crust,effectively improving strength and reducing engineering issues during construction and service. Based on a field test in the Chaoshan area of Guangdong,this study evaluated the treatment effect of a 6 m in-situ stabilized layer under rapid post-stabilization filling. A numerical model was established to investigate the influence of stabilization thickness,elastic modulus,and loading on the treatment performance. Field observations indicated that the 6 m stabilization effectively reduced compression of the soft layer and controlled horizontal and uplift displacements induced by the fill load. Numerical simulations further showed that settlement decreases nonlinearly with increasing stabilization thickness and modulus. The magnitude of the applied load dominated both settlement and excess pore-water pressure in the foundation. It was also found that both elastic modulus and stabilization thickness affect settlement of the in-situ stabilized foundation,but settlement sensitivity to thickness differs markedly from that to modulus. With greater stabilization thickness,settlement becomes more sensitive to changes in modulus. Additionally,stabilization thickness has a more pronounced impact on settlement than elastic modulus. Elastic modulus is linearly related to cement content: cement-silt stabilized soil with moduli of 10 MPa,20 MPa,40 MPa,and 60 MPa corresponds to cement contents of 4%~5%,6%~7%,9%~10%,and 11%~12%,respectively. Numerical analysis suggests that for this case the most economical elastic modulus is 28 MPa(corresponding to a cement content of about 8%)and the most economical stabilization thickness is 3.2 m.