Abstract: A new method that adopts additional stress and probability integration to reasonably evaluate foundation stability is applied to provide a scientific basis for the engineering construction of old goaf.Taking the material base to be built by Shijiazhuang Iron and Steel Company for example, the method is adopted to analyze the impact of engineering construction of old goaf, and the conclusion is that the load of building does not make old coal goaf awake.The residual deformation of old goaf is within the allowable range and almost does not affect to engineering construction.It is basically feasible to construct project above the old goaf, and the evaluation provides a scientific basis to build projects over the goaf.

Key words: Old goaf, Foundation stability, Additional stress, Probability integral method