Experimental Study On The Residual Deformation Law Of Goaf Overlying Strata And Surface Under Load

In recent years, the rapid development of cities caused increasingly tense of land resources in coal mining areas. Especially less and less land were available for construction in some old coal mining areas. When construct buildings above the mined-out area, the caving broken rock strata and construction load in the gob will produce compaction secondary deformation, and when the Mined out area used for construction land should be considered the residual deformation. So to carry out the relevant analysis and experimental research, explore the residual deformation law and its mechanism.In order to analysis the characteristics of rock mass above the goaf and the surface deformation under load, and reveal the mined-out area secondary deformation mechanism. In this paper, New industrial square of a mine in Huainan as the research object, using FLAC3D numerical simulation method, inversion analysis of the surface residual deformation law under construction load and the different load location, size, above old goaf. The results showed:Goaf edge within the residual deformation and surface movement is the largest; the smallest is the middle area and the outer fringe area is in the middle. Under the same condition of load position, with the increase of load, the surface residual deformation value is more and more big. Using the broken rock compaction simulation experiment device (ZL201320783166.6) to do compaction experiment on goaf and broken rock mass.The results show that consolidation settlement of soil would be appeared due to water loss no matter with pressure or not, and the deformation of fine particle soil was larger than that of coarse grain size soil under the same load condition. The stress-strain and the time-strain relation can be approximated as a power function in conditions of natural state. The time-strain relation can be approximated as a linear function in conditions of water coupling. It can provide a reference for old goaf residual deformation control and management information. The experimental results can provide the reference data for above goaf building foundation residual deformation control and management.