Stability analysis of tunnel under coal seam goaf:Numerical and physical modeling  

作　　者：Feng Huang Xiaoxiong Shi Chuangzhou Wu Guangfa Dong Xingchen Liu Aichen Zheng 

机构地区：[1]State Key Laboratory of Mountain Bridge and Tunnel Engineering,Chongqing Jiaotong University,Chongqing 400074,China [2]School of Civil Engineering,Chongqing Jiaotong University,Chongqing 400074,China [3]Department of Geophysics,Kangwon National University,Chuncheon,Gangwon-do 24341,Republic of Korea

出　　处：《Underground Space》2023年第4期246-261,共16页地下空间（英文）

基　　金：supported by the National Natural Science Fund of China(Grant No.52078090);the general program of Chongqing Natural Science Foundation(Grant No.cstc2020jcyj-msxmX0679);the Fund of State Key Laboratory of Mountain Bridge and Tunnel Engineering(Grant Nos.SKLBT-19-006,SKLBT-YF2106).

摘　　要：The goaf formed by coal seam mining would dramatically reduce the strength and stiffness of the ground in and around the goaf,which is not conducive to tunnel excavation near the mined-out area.By establishing the Finite differential method and Discrete element method coupling numerical analysis method and conducting similar model test,the influence of dip angle,thickness and distance of coal seam goaf on the stability of unsupported tunnel excavation is studied.The results show that when the tunnel under the goaf is exca-vated,the circumferential stress increment increases first and then decreases along the radial direction of the tunnel,the radial stress increment gradually decreases to zero along the radial direction of the tunnel,the displacement is approximately distributed in a trough shape,and the maximum displacement is at the top of the tunnel.The area of the stress loosening zone(SLZ)is negatively correlated with the dip angle and the distance of the goaf,and positively correlated with the thickness.The SLZ near the goaf is larger,and the peak value of the asymmetry is about 1.35.When the thickness of the mined-out area is 1.8–2.1 m,the SLZ and displacement around the tunnel increase sharply and then become stable.When the dip angle of the mined-out area is greater than 30°or the distance exceeds 1.3 times tunnel diameter(D),the asymmetry converges.The research results of this paper are of great importance to the design and construction of tunnel support and the formulation of excavation schemes.

关 键 词：TUNNELING Stability analysis Coal mine goaf Coupled FDM and DEM Experimental model 

分 类 号：TD7[矿业工程—矿井通风与安全]