片麻岩大断面双洞隧道施工的动态特性  

Dynamic characteristics of construction of twin tunnel with gneiss large section

作　　者：张浩亮[1] 李忠[1] 朱彦鹏[1,2] 陈思阳[1] 

机构地区：[1]兰州理工大学土木工程学院,甘肃兰州730050 [2]兰州理工大学甘肃省土木工程防灾减灾重点实验室,甘肃兰州730050

出　　处：《兰州理工大学学报》2013年第5期100-105,共6页Journal of Lanzhou University of Technology

摘　　要：以兰州市北环路大断面双洞隧道工程为研究背景,采用台阶法进行施工,以ADINA有限元软件为计算平台,建立隧道开挖数值模型,对片麻岩大断面双洞隧道模型进行分析:研究地表位移、围岩位移与内力、锚杆轴力的特点及其变化规律.结果表明对片麻岩大断面双洞隧道采用台阶法施工时,分步开挖对地表竖向位移较水平位移影响大,最大竖向位移值为10.71mm,位于双洞隧道间岩柱上方;上、下台阶土体开挖会对隧道围岩位移及等效应力产生较大影响,应及时进行拱顶初期支护;锚杆轴力集中分布于边墙部位,且沿其辐射方向呈现不断减小的趋势,应对边墙部位锚杆进行加强处理.Taking the construction project of twin tunnel with large section on the north belt highway in Lanzhou as investigation background and the step method was used for its construction, a numerical model was established for tunnel excavation with finite element software ADINA as calculation platform and the model of twin tunnel with gneiss large section was analyzed. The ground displacement, displacement and internal force of surrounding rock, and distribution characteristics and variation pattern of axial force in the anchor rod were all studied. The results showed that when the step method was adopted to the construc- tion of the gneiss large section tunnel, step-by-step excavation would have much more effect on ground vertical displacement than on horizontal displacement. The maximum vertical displacement was 10. 71 mm that located at the top of the tunnel rock pillar in the middle of the twin tunnel. Soil excavation would have greater influence on the displacement and equivalent stress of the surrounding rock which shoukt be timely vault initial support. The axial force of anchor rod was concentrated in tile side wall and decreased along its radiate direction, so the anchor rod located in the side wall should be reinforced.

关 键 词：片麻岩 大断面 数值分析 台阶法 

分 类 号：TU43[建筑科学—岩土工程] U45[建筑科学—土工工程]