Distribution laws of ground stress after newly increased load on surface above mined-out areas

New buildings exert extra load on the ground surface above mined-out areas and may induce overburden failures. A systematic research on the distribution laws of foundation stress after newly increased load on mined-out areas is performed by use of simulation tests on similar materials and numerical methods. The main findings are as follows: the rock stress increases lineally with the depth before the coal mining, while it has a redistribution after the coal worked-out. The additional stress of the foundation decreases gradually with the depth after the newly increased load on the surface. The influence depth is determined by the foundation additional stress caused by newly added load when it is equal to 10% of the rock stress before the coal mining. The influence depths under different loads on the surface before and after mining are obtained, and the study provides an important theory criterion for surface utilization above mined-out areas.