砂卵石地层重叠隧道开挖顺序优化研究  

Optimization of the Excavation Sequence of Overlapped Tunnels in Sandy Cobble Stratum

作　　者：黄园园[1] 漆泰岳[1] 王睿[1] 冯剑[1] 

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、土木工程学院,成都610031

出　　处：《现代隧道技术》2013年第5期52-59,共8页Modern Tunnelling Technology

基　　金：国家自然科学基金项目(51278423);中央高校基本科研业务费专项资金项目(WSJTU11ZT33)

摘　　要：成都地铁2号线重叠隧道盾构在砂卵石地层中施工属国内少见工程,文章对此采用数值模拟和现场实测相结合的方法,研究分析了砂卵石地层盾构施工采用不同开挖顺序、经两次扰动的地层移动特征,以及对结构的受力影响;根据区间隧道由并行段渐变到交叉段,建立FLAC3D三维数值模型,对盾构施工全过程进行分析,并结合实测资料模拟盾构超挖产生的影响。结果表明,重叠隧道采用先下洞后上洞施工顺序较合理,盾构超挖后造成大的地层损失使地表沉降增大约一倍,盾构开挖的二次扰动使上洞上方土体发生较大的沉降,下洞稍稍隆起;数值模拟与实测结果得到较好的一致性。The construction of overlapped shield tunnels in sandy cobble stratum, such as in the ease of the Chengdu metro line 2, are rare in China. Therefore a method combing numerical simulation and field measurement is adopted to study the movement characteristics of the twice-disturbed ground and the effects of the force applied on the structure under different exaction sequences. A FLAC3D numerical model is established to analyze the whole process of shield construction from parallel section to overlapped section; and to simulate the effects by shield overcut based on practical measurements. The results show that it is relatively reasonable for the overlapped tunnels to take the excavation sequence from lower tube to upper tube; ground loss induced by shield overcut results in an increase of ground surface settlement up to two times; large settlement occurs above the upper tube; and the lower tube heaves slightly due to a secondary disturbance by the shield construction. The numerical simulation agrees well with the practical measurements.

关 键 词：砂卵石地层 重叠隧道 开挖顺序 数值模拟 地表沉降 地层损失 

分 类 号：U455.43[建筑科学—桥梁与隧道工程] U456.1[交通运输工程—道路与铁道工程]