In a hypothetical severe accident in light water reactors, a deep pool of water is employed in the lower drywell of the containment, to cool the core melt materials discharged from the reactor pressure vessel. By contact with water, the molten corium will fragment, solidify and settle at the bottom as a porous debris bed. The preeminent goal becomes how to prevent the re-melting of the debris in consequence of insufficient cooling. One of the main factors affecting the ability of decay heat removal is the geometrical configuration of the bed, which can also change due to the particles redistribution induced by steam production within the bed. In this work, the influence of steam production on bed formation was investigated experimentally with the dedicated BeForE-facility. A series of experiments were conducted by discharging solid particles in in two-dimensional viewing vessel, while air bubbles simulating the steam production are injected simultaneously from the bottom. Depending on the quantity of the settled particles on the top of each section of the vessel, air flow rate is so monitored and adjusted in time to simulate the corresponding amount of steam produced by the similar quantity of debris. Based on the obtained experimental results, a numerical model is established to simulate the two-dimensional debris bed formation under the influence of steam production.