Abstract:
The aim of surface monitoring and data analysis is to determine the law of surface movement and parameters of prediction.The prediction of surface subsidence is used for the evaluation of mining damage degree.Whether the field monitoring data are used for the analysis or prediction of surface deformation,the surface slope,curvature and strain are derived from the two components,i.e.surface subsidence and horizontal movement.Uneven mining subsidence may cause surface tilt and curvature change,and result in building deformation and damage.The impact regularities to strain are obtained by analyzing the uneven subsidence and topography on the deformed configuration.The expressions of horizontal deformation derived from mining slope are established under the conditions of horizontal surface and terrain undulation,respectively.The relationships between the length,height,maximum deflection,deflection ratio of structure and the positive curvature of surface are analyzed and determined.The elongation and tensile strain for upper structure are calculated qualitatively.The behavior of a structure in a curvature area and its damage features are given further under tensile and shearing conditions.Based on the inheritance of advantages for the classification criterion of mining damage in the current Chinese standard,and reference to the damage degree with the change of building length in Subsidence Engineer’s Handbook,a synthetic classification indices to building damage are established.The structure length,horizontal strain and the building deflection ratio are considered in order to improve the disadvantage of stiff classification and the fuzziness of reclassification for damage category I and IV.The site experiments show that the longer the structures the severe the mining damages under the same surface deformation conditions.This demonstrate that the new indices are reasonable and objective compared with traditional stiff method in current specification.The uncertainty and fuzziness to the further reclassifications for building damage category I and IV are avoided.