Abstract: Taking mined-out area underlying new building 11^# belonging to Guye Branch in Tangshan as a case, the numerical analysis of buildings' stability above was proceeded by discrete element code(3DEC). According to the distribution and rock stratum information of mined-out area surveyed, 3-dementional numerical model was established by using the method from the whole to the individual, to analyze the stability of mined-out area with and without disposal. By simulation, the settlement of monitoring points is about 20cm without disposal, and the settlement of monitoring points is about 3.5cm under the condition of simulating the physical characteristics of grouting to treat the mined-out area. Simulation results show that the settlement is within the building settlement range after mined-out area disposed, and this provides a reference criterion for construction. 

Key words: Building, Mined-out area underlying, 3DEC, Stability