Abstract:Cavity expansion theory is a common method to establish engineering models of penetration problems. For the penetration problem of cellular steel-tube-confined-concrete (STCC) targets, a quasi-static spherical cavity expansion model is firstly developed on the basis of inclusion of the comprehensive confinement of steel tube and the peripheral concrete on the impacted cell and the assumption that failure behavior of concrete obeys the Hoek-Brown (H-B) criterion in the comminuted region; and then influences of the comprehensive confinement stiffness on the penetration process are analyzed. The numerical results show that the radial stress of STCC targets on the cavity wall does not remain constant during the expansion process, which is different with those of infinite concrete targets; and the pressure on cavity wall increases with the increase of the comprehensive confinement stiffness; and the predicted results of depth of penetration are in good agreements with those of experiments in the existing literatures.