Research On Overburden Movement And Ground Deformation Under Large Mining Depth And Thick Loose Layer Conditions

Based on the mining of deep thick unconsolidated strata in North No.2 Mining Area of Hongyang No.3 coal mine,this paper uses similar simulation test,theoretical analysis,numerical simulation test and other research methods to reveal the rock movement law and surface deformation characteristics of deep thick unconsolidated strata mining.The main achievements are as follows:(1)Based on the similar simulation test of deep mining,the control effect of key strata on overlying strata under the condition of deep mining is explained,and the mechanical structural models of fixed beam and masonry beam in the deformation process of basic roof are revealed,and the fracture step under the two structural mechanical models is calculated.(2)Through numerical simulation,the role of bedrock and loose layer in surface movement is studied.When the bedrock is thin,when the thickness of loose layer gradually increases,the bedrock surface is subjected to simple load;When the thickness of the loose layer reaches a certain degree,the continuous increase of the load will lead to the saturation of the settlement in the bedrock.In this stage,the loose layer plays an obvious role in the load,which will aggravate the surface deformation.When the thickness of the loose layer continues to increase,the surface deformation decreases,and the buffer effect of the loose layer is obvious.The thinner the bedrock is,the greater the impact in a short time.The loose layer determines the influence scope and damage degree of mining subsidence.(3)Based on whether the key layer is broken or not,the two factor surface subsidence model of bedrock and loose layer is established.When the key layer is not broken,the bedrock movement model is established according to the elastic foundation beam theory.When the key layer is broken,the bedrock movement model of "masonry beam" is established,Based on the random medium theory,the bedrock movement model is coupled with the loose layer probability integral method model to obtain the final surface subsidence model,and the surface subsidence model is compared with the measured data,which shows good fitting and high reliability.There are 38 figures,14 tables and 82 references in this paper...