Punch-through is one of the main threats to the safe operation of jack-up units. Perforation method has been successfully implemented in engineering practice to mitigate punch-through potentials. However its research and evaluation method are still limited. With the coupled Eulerian-Lagrangian method provided by ABAQUS

finite element analysis of punch-through mitigation with perforation is carried out. The spudcan is modeled as Lagrangian domain

while the soil is modeled as Eulerian domain

among which the holes created by perforation drilling is initially modeled as void. The mechanism by which perforation mitigates punch-through potential is analyzed

which shows that the perforation drilling turns general failure mechanism into local failure mechanism in stiff-over-soft clay layers. And the effects of hole number

hole depth

hole diameter and extent are studied. It is shown that the soil plug during penetration into stiff-over-soft clay decreases with hole number

hole depth and hole diameter. Correspondingly

the efficiency of punch-through mitigation with perforation is proportional to hole number

hole depth and hole diameter. However

the effect of hole diameter on the peak resistance is relatively very small. The extent of drilling holes outside the spudcan perimeter has little effect on the peak resistance

while it has a larger effect on the post-peak resistance. An evaluation method for the efficiency of peak resistance reduction with perforation method is proposed by fitting from 75 cases of numerical simulation. It takes into account the perforation drilling area both outside and inside the spudcan perimeter; hole diameter and hole depth

which is of great significance for engineering practice.