大跨小净距隧道衬砌力学行为现场测试研究  

RESEARCH ON LINING MECHANICAL BEHAVIOUR OF TWIN TUNNELS WITH A BIG SPAN AND A SMALL SEPARATION BY FIELD TEST

作　　者：张恒[1] 陈寿根[1] 程芳卉[2] 

机构地区：[1]西南交通大学交通隧道工程教育部重点实验室,成都610031 [2]中铁第一勘察设计院集团有限公司,西安710043

出　　处：《工业建筑》2012年第12期53-57,103,共6页Industrial Construction

摘　　要：综合采用现场测试及数值计算方法,对深圳市南坪快速II期双洞八车道小净距隧道施工中二衬受力分布规律,以及不同间距下近邻隧道施工后行洞对先行洞二衬结构受力的影响进行研究。研究结果表明:二衬各点轴力和弯矩值均较小;拱顶处、远离中岩柱侧的边墙和中岩柱侧拱脚部位有可能出现较小拉力,应注意防止混凝土开裂;Ⅳ级围岩、30 m净距条件下,后行洞开挖对先行洞支护受力的影响范围为掌子面后方40 m内,围岩越好,影响范围越小;仅拱顶处主应力表现为受拉,其余部位表现为受压,其中左、右拱脚处主应力压力值最大。随着净距的逐渐增大,拉应力与压应力值变化很小,没有一致增大或减小的趋势,净距变化对支护的应力影响不明显。By utilizing an integrated method of field tests and numerical modeling the law of force distribution in second lining, it was studied the effect of the adjacent construction of following tunnel on the existing tunnel with different spacing of a eight-lane twin highway tunnel with a big section and a samll separation on the Shenzhen Nanping Expressway（Stage Ⅱ ）. The research results showed that the axial force and bending moment values of each measuring point in second lining were much small. It was possible to be a smaller tension in vault, the side wall away from the intermediate rock specimen and the arch foot of the intermediate rock specimen, attention should be paid to preventing the concrete cracking. The influence scope of the following tunnel excavation on the existing tunnel reinforcement force under the condition of 30 m spacing and IV surrounding rock was within 40 m at the rear of the tunnel face, and the better the surrounding rock the smaller the influence scope. Only the principal stress in vauh was subjected to tension, and the other parts were under pressure, of which the maximum principal stress was on in the left and right arch foot. With the spacing gradually increasing, the tensile stress and compressive stress values changed little, there was no consistent trend of increase or decrease, the effect of spacing changes on the supporting stress was not obvious.

关 键 词：现场测试 大断面 小净距 力学行为 

分 类 号：U451.4[建筑科学—桥梁与隧道工程]