【作者】 张超；

【导师】 陈寿根；

【作者基本信息】 西南交通大学 ， 建筑与土木工程（专业学位）， 2018， 硕士

【摘要】 随着我国城市地铁建设进程的不断推进,城市地铁线路日益增多,而城市浅层地下空间毕竟有限,盾构小净距隧道成为了城市地铁隧道的必然选择。目前,对于小净距隧道的研究多集中在两隧净距大于1倍洞径的山岭隧道,对于两隧净距小于1倍洞径的地铁隧道方面的研究较少,与前者相比后者两隧相互影响更加显著,结构受力、变形更加复杂。对净距小于1倍洞径时,不同净距条件下,两隧相互影响规律进行系统的研究就显得十分必要,并能为地铁施工提供重要的参考价值。本文以深圳地铁7号线笋岗~洪湖区间盾构小净距隧道工程为依托,综合采用模型试验和数值计算等研究方法,对以下几个方面进行了研究:(1)通过两隧重叠与两隧平行两组各3种净距工况模型试验,研究分析了不同净距条件下,右线(新建)隧道开挖对左线(既有)隧道的衬砌位移变化、衬砌内力(弯矩和轴力)变化影响规律。(2)通过两隧重叠与两隧平行两组各5种净距工况数值计算,研究分析了不同净距条件下,右线隧道开挖对左线隧道衬砌位移变化、衬砌内力变化影响,以及不同净距条件下地表沉降和围岩塑性区分布规律。(3)通过对模型试验和数值计算结果对比,二者相互印证、相互补充,总结了净距小于1倍洞径时,在不同净距条件下右线隧道开挖对左线隧道的影响规律。总的来说,净距小于1倍洞径时,随净距增大,右线隧道开挖对左线隧道影响逐渐减弱。左线隧道衬砌靠近右线隧道一侧所受影响较为显著。由于两隧净距较小,其周边围岩及两隧夹持土体均发生塑性破坏且塑性区贯通,对二者进行必要的加固是工程实际中必需做好的工作。更多还原

【Abstract】 With the advancement of the urban subway construction process,the city subway line is increasing.But the shallow underground space of city is limited,shield tunnels with small-spacing has become the inevitable choice of city metro tunnels.At present,the research of tunnels with small-spacing focused on mountain tunnels which net distance is greater than 1 times of the hole diameter,the part of the metro tunnels which net distance is less than 1 times of the hole diameter is less.The latter two tunnels influence each other even more significant compared to the former,structure stress and deformation is more complicated.When the net distance is less than 1 times of the hole diameter,it is necessary to study the interaction law of the two tunnels with different net distance,which can provide important reference value for subway construction.Based on Shen Zhen metro line 7th SunGang~HongHu running shield tunnels with small-spacing engineering,integrated using the methods of model experiment and numerical calculation,studied the following aspects:(1)Through 3 kinds of net distance tunnel model tests of two tunnels overlapped or parallel,the research analyzes the effect of the left line(existing)tunnel by the right line(new)tunnel excavation when under different net distance conditions,include the change of lining displacement,internal force(bending moment and axial force)of the left line(existing)tunnel.(2)By 5 kinds of net distance numerical calculation of two tunnels overlapped or parallel,analyzed the effect of the left line tunnel by the right line tunnel excavation with different spacing.Which include the changes of internal forces and displacement of tunnel lining,and the distribution regularity of surface subsidence and plastic zone of surrounding rock.(3)By comparing with the result of model test and numerical calculation,they mutual support and complement,summarize the influence law of the left line by the right line tunnel excavation with different spacing when the net distance less than 1 times of the hole diameter.In general,when the net distance is less than 1 hole diameter,the effect of right-line tunnel excavation on the left line tunnel will gradually decrease as the net distance increases.The left-line tunnel lining near the right side of the tunnel is significantly affected.Due to the small clearance distance between the two tunnels,the plastic zone of the rock surrounding the tunnels is broken,especially the rock mass between the tunnels.And the plastic zone is connected.The necessary reinforcement for both is the necessary work in the engineering practice.更多还原