Evaluation of foundation stability in coal mine subsidence area and deformation resistance technology

To scientifically use the coal mine subsidence area for surface buildings and to ensure the safe and normal use of new construction structures, this work systematically examines the foundation stability evaluation method, foundation treatment technology, and deformation resistance technological measures of new constructions in goafs by combining theoretical studies and field practices. Determining the minimum mining depth larger than the sum of height of fracture zone and the influence depth of building load when constructing surface buildings over goafs is suggested. The height of new constructions must be determined with considerations to the surface's residual subsidence deformation, especially its inclination deformation. Moreover, the grouting treatment of goafs must be considered when the mining depth is too low or the geological mining conditions are too complicated to meet construction requirements. Deformation resistance technological measures of construction include the plane layout of stress to pursue simple and regular shapes, as well as regular and uniform vertical shapes; furthermore, it involves using sand or sand-gravel cushion if bearing capacity is allowable, setting a horizontally sliding layer when the building height is smaller than 60 m utilizing strip foundation, slab foundation, beam plate or box foundation, and increasing plan view size and strength of foundation of high-rise buildings appropriately, increasing building strength, among others. These technologies have been applied extensively in resource cities such as Pingdingshan, Tangshan, Jincheng, and Jiaozuo, achieving remarkable economic and social benefits.