With numerous developments taking place around the world, land becomes more and more precious. There is an increasing need to consider building infrastructure on the land that used to be treated as uneconomical or potentially dangerous because of abandoned underground mines. Underground mining can result in surface subsidence that manifests itself as sagging and cracking of the ground surface. Surface subsidence may occur suddenly and cause severe damages to the surface infrastructure [1]. In longwall mining, the overburden strata of a coal seam are disturbed and typically form three zones of disturbances, as shown in Fig. 1, in response to the mining [2]. Equilibrium can be developed in the disturbed overburden, as well as a simultaneous subsidence on the surface, with the consolidation of the caved zone after mining operations [3]. Occasionally, equilibrium is perturbed which leads to further surface subsidence. Such subsidence can occur decades or even 100 years after mines were abandoned [4-6]. In such cases, besides the factors such as the geological conditions, surface topography, groundwater and extraction percentage of underground mines [7], it is important to take into account the creep behaviors of the disaggregated rocks in caved zones under constant loadings of overburden strata.
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