(1. State Key Laboratory for Geomechanics and Deep Underground Engineering,China University of Mining and Technology,Xuzhou,Jiangsu 221116,China;2. Changchun Gold Design Institute Project Construction Supervision Department,Changchun,Jilin 130012,China;3. School of Civil Engineering and Architecture,Henan University,Kaifeng,Henan 475004,China;
4. China Railway Tunnel Survey Design Institute Co.,Ltd.,Tianjin 300133,China)
Abstract:3D numerical simulation with FLAC3D,was carried out to investigate the interaction between double shield TBM and composite ground. The real TBM geometry and the non-uniform annulus gap between ground and TBM shield were considered. The characteristics of surrounding rock deformation,the contact force and the frictional resistance acted on the shield of TBM in composite ground were studied at the following conditions:(1) weak rock layer occurs along the ground depth;(2) soft rock occurs along the axial direction of tunnel;and (3) different lengths of soft and hard rock alternating in the longitudinal direction. Meanwhile,the non-uniform annulus gap was introduced to the calculation of contact force acting on the shield as a function. In case (1),the curve of longitudinal displacement profile of surrounding rock came into contact with the TBM shield successively from bottom to top,which affected by the non-uniform annulus gap. The contact zone was mainly situated on the sidewall and below and the contact force was largely concentrated on the middle and tail end of both front shield and rear shield. The maximum magnitude of contact force occurred in the end of front shield. In case (2),the frictional resistance acting on the shield was increased and finally kept in steady state with the increasing length of soft rock. In case (3),the magnitude of the contact force acting on the shield was in periodic fluctuation and was basically in accordance with the variation of displacement. Moreover,the shapes of longitudinal displacement profile(LDP) curve in composite ground in cases (2) and (3) were absolutely different from that in homogeneous rock mass.
黄 兴. 深部软弱地层TBM掘进围岩挤压大变形与卡机致灾机制[博士学位论文][D]. 武汉:中国科学院武汉岩土力学研究所,2014. (HUANG Xing. Mechanism of Large squeezing deformation and shield jamming in deep soft ground tunneling by TBM[Ph. D. Thesis][D]. Wuhan:Institute of Rock and Soil Mechanics,Chinese Academy of Sciences,2014.(in Chinese))
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