Abstract In order to evaluate the stability of the foundation of new building on top of the old goaf which was not described in the present design codes,the analysis of overburden structure is carried out. The surface residual movement is firstly defined with two deformational phases. Only the second phase of the residual movement and deformation is found to cause harmful effects on the surface building. The compaction characteristics of the caving rock from boundary to the central of the old goaf is found to be different,with the border zone of voids,the central zone of collapsible rock voids and the fissures in upper rock. The regional space of two groups of the old goaf governing the surface residual and deformation are converted into the equivalent mining thickness respectively. The influence functions of the static surface residual deformation are constructed using the integral theory of probability under the influence of mining,including the influence functions of residual subsidence,the residual horizontal movement,the residual tilt deformation,the residual horizontal deformation and the residual curvature. The results of calculation using these influence functions show that the maximum residual movement and deformation of the surface occur at two border sides of the old goaf. The creep characteristics of rock are analyzed with Kelvin model and the time function of the residual subsidence coordinates constructed for the dynamic analysis of residual subsidence. It is verified that the results from the influence functions agree well with the actual observational data and the numerical simulation with FLAC3D.
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Received: 30 September 2013
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