| The coal mining inevitably brings about a series of problems which making many negative effects on the natural environment and people's life,such as the cracks appeared on the walls of the house,the local subsidence of the fields causing the accumulation of water,the large area occupied by the coal gangue making the environment polluted,and more dust in the air and etc.In recent years,with the rapid development of all walks of life in China,as well as the approaching of “the first 100 years”,a large number of public infrastructures would be built in various places,thus the large-scale land would be used,in the end,contradictions between more people and less land would become a roadblocks on the road of development,therefore,it is necessary to make full use of various land resources to provide dynamic support for development.Therefore,the feasibility of building industrial plants on the mining subsidence area and the stability of the backfill foundation with the mixture of coal gangue and fly ash were analyzed in this paper with the engineering research background of the port mining area of Ningguo,and then the abandoned land caused by coal mining was reestablished to achieve sustainable development of land resources.In this paper,the surface movement deformation of the treatment area was predicted by a mathematical model established by the probability integral method,the results showed: that the treatment area was outside the 10 mm sinking contour range,and the surface would not sink in the future,so the coal mining subsidence area was provided with prerequisites for the construction of industrial plants.In order to prevent the influence of deep underground caverns on the reliability and safety of industrial buildings in the subsidence area,the stability of it was detected by the three-pole electric sounding technique.The detection report showed that the uneven settlement of ground surface would not appear in the foundation of goaf after backfiled reinforcement,then it was reasonable and reliable enough to build industrial plants.In addition,the instability was analyzed which industrial plants were built on coal mining subsidence area at the port mining area,the results showed that it is safe and reliable as well as stability and feasibility to build industrial plants on coal mining subsidence area in theory.Then the related tests were carried out on the backfill materials such as coal gangue and fly ash.The engineering application of them just as backfill materials was analyzed from the aspects of physical chemistry and mechanics.The test results showed that the both indicators of them met the limits specified by the standard,such as the CBR value of coal gangue,the ignition loss of coal gangue,the ignition loss of fly ash,the fineness of fly ash etc,thus both of them were suitable as backfilling materials for industrial plants foundation.In order to analyze the overall stability and bearing capacity of the foundation backfilled by gangue-fly ash mixture,the stress-strain and settlement law were analyzed under different loads according to the actual project situation by numerical analysis software FLAC3 D.The simulation results showed that the model is unstable under different loads,and the maximum settlement was only 77.839 mm under the maximum concentrated load of 1000 kN,which was far less than the 120 mm requirement of the specification.It was enough to prove that the foundation had enough bearing capacity and stability.Finally,the construction technology for backfilling building foundation with coal gangue fly ash mixture was put forward to achieve scientific and efficient guidance of engineering construction drawing on the successful experience of coal gangue backfilling highway subgrade. |
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