Study On Evolution Law Of Mining Overburden Separated Strata And Surface Subsidence Model

With the rapid growth of C hina's economy,energy use is increasing,the scale of mining of mineral resources continues to expand,which led to the mining subsidence problem become increasingly serious.The exploitation of mineral resources will inevitably cause overburden movement,in this process,separation phenomenon is widespread,and plays an important role in transfer,to a certain extent the control the generation of surface subsidence.So evolution law o f mining overburden separated strata and surface subsidence rules for further research,and establish a surface subsidence model based on evolution of separation has important theoretical and engineering value.This paper firstly theoretically analyzes the mechanical mechanism of separation to produce,the relationship model of overburden separation development and dynamic surface subsidence is established on the basis of separation and surface morphology.After using the similar material simulation experiment from the separation spatial layers,horizontal expansion,synergetic theory and other aspects to describe the evolution of separation,analysis of the relationship between separation evolution and surface subsidence,and establishes the model of surface subsidence separation based on separation evolution.Finally,numerical simulation method is used to study the distribution law of overburden movement,stress field and vector field,to further validate the expansion rule of the separation and overburden movement characteristics.The main research results are as follows:(1)The separation is caused by non synchronous subsidence of adjacent strata,contains two kinds of mechanical models,one is the shear crack;second is interlayer crack.Dynamic surface subsidence and separation development has a one-to-one relationship in the horizontal,non full mining separation causes surface non fully subsidence,sufficient mining separation causes surface fully subsidence,overfull mining separation causes surface subsidence over ful.(2)Separation has gone through three stages,namely: crack-expansion-closed,separation spatial distribution affected by the mining width and the fracture angle,arched form,and is located in the unloading zone.O verburden failure degree and separation space decreased gradually from the down to up,and the evolution of separation showed obvious synergistic effect.(3)The surface dynamic subsidence is divided into three stages: initial stage,active stage and decline stage,and the movement of surface points is divided into 4 stages,the mobile trace curved.(4)The mining overburden can be divided into three vertical zones and three horizontal zones.The fracture rate of open-off cut and stop line is the highest,and the fracture rate in the middle of the goaf is low,and establishes the relationship between surface subsidence and fracture rate.(5)By similarity simulation experiment,analysis of the spatio-temporal relationship between surface subsidence and separation development,establish the model of surface subsidence based on separation spatial distribution law,and on the basis of elastic mechanics and material mechanics,established the model of surface subsidence based on elastic beam.