Experimental and numerical investigation on saturated concrete subjected to underwater contact explosion

Abstract

The hydraulic concrete structures were partially or fully in direct contact with water during the service life. The mechanical properties of saturated concrete are different from dry concrete because of the presence of water. To investigate the underwater blast resistance mechanism of saturated concrete, saturated concrete slabs were first tested in underwater explosion experiments with different TNT masses of 2.5 g, 5 g, and 10 g. The experimental results showed that the crater on the front of the concrete slab was smaller than those on the back and the size of the crater increased with increasing mass of TNT. Numerical simulations were conducted and material parameters were determined based on additional tests: The damage model under different stress states was proposed by repeated loading and unloading tests in tension and compression under different confining pressures. The damage model was then embedded into the Holmquist-Johnson-Cook (HJC) model. Quasi-static and dynamic compression experiments were conducted to determine the material parameters of the saturated concrete. A three-dimensional fluid-solid coupling numerical model in ABAQUS was proposed for simulating the underwater explosion and its interaction with the saturated concrete slab. Finally, the mechanisms that produce differences in the damage pattern of concrete slabs at different explosive masses are revealed.