Foundation Stability Analysis Of Newly Buildings On Old Goaf Surface

With the rapid development of China's economy and the increasing demand for resources,coal plays an important role in China,s energy as a non renewable resource.However,with the exploitation of large amounts of coal resources,the land wasted in old mining areas has become a new problem.In order to ease the shortage of Iand resources and make full use of the subsidence land in old mining areas,it is very necessary to study the foundation stability of the old mining area under the new building load.This paper is based on the newly building(experience building)in the 11 old mining area of Shandong ancient coal mine,and uses the combination of theoretical analysis and numerical simulation.Firstly,according to the measured data,the law of surface deformation is studied.At the same time,the surface deformation value of mining in 11 mining area is predicted by using the probability integral method,which provides theoretical support for numerical simulation using finite difference software;Second,the finite difference software was used to simulate the surface deformation under different mining conditions;Then,based on the numerical simulation of mining,the building load is applied to simulate the relationship between different influencing factors and the surface subsidence value;Finally,the experimental model foundation stability under the load of experience area 1s analyzed.The following conclusions are obtained through the study and analysis,(l)Collecting surface observation data during strip mining in 11 mining areas and process analysis,using the improved genetic algorithm to retrieve the surface movement parameters in the range of measured area,and using the probability integral method to predict the surface movement after the mining area of the range working face,and get a good prediction effect;Through research and analysis of measured subsidence data of surface observation points during the construction and operation of new buildings,it can be seen that the monitoring points near the buildings have stabilized.(2)FLAC 3D software is used to simulate the surface deformation under different working conditions,and the relationship between the main factors such as mining width,retaining width,recovery rate,mining depth,the loose layer thickness and surface movement deformation law is obtained.(3)FLAC 3D software was used to simulate the residual deformation of the surface under the action of building loads.The influence of loading position,load level,depth of mining,loose layer thickness,and load size on surface subsidence was obtained.(4)By analyzing the relationship between the influence depth of the building load and the height of the crack zone,it can be concluded that the building load of the experience building will not be directly loaded into the fracture zone,which will not directly lead to the "activation" of the old goaf.