In the dense sand-over-clay strata, there is a potential for an installing spudcan to experience a sudden uncontrolled punch-through failure. Such a punch-through failure would seriously threaten safety of the rig structure, even cause casualties. To estimate the potential spudcan punch-through failure, this paper presents a simplified numerical method to calculate the full load-penetration resistance profile. The present approach allows the progressive failure of the overlying dense sand to be properly simulated by using an extended Mohr-Coulomb model. A series of large deformation finite-element (LDFE) analyses are carried out, varying the strength parameters. A fairly good performance of the present approach is verified by validating against groups of centrifuge tests data. Additionally, comparisons with the typical existing LDFE analyses in which both the simple and sophisticated constitutive models are conducted, show that the present approach performs fairly well to calculate the penetration resistance of a spudcan on dense sand overlying clay.