摘要
预切槽法开挖隧道能够很好地控制地表沉降,适用于包括黄土在内的软土地层,但如何约束预衬砌的墙脚是预切槽法亟待解决的问题。本文依托洪亮营隧道,首先通过数值模拟方法,论证了约束墙脚可以提高预衬砌结构安全度,并选择锁脚微型桩来加固墙脚;之后基于桩基承载机理,提出刚度分配法,确定了桩的受力、最佳打设角度和最优间距。研究表明：加强墙脚的约束,可以提高预筑拱结构在拱腰和拱顶的安全系数,减小拱顶的沉降;T76S桩能够满足锁脚要求,锁脚桩与竖直方向之间的角度在20°-50°时桩的受力最为合理。
The precutting methods of tunnel excavation can effectively control the ground settlement,suitable for soft soil layer,including loess. But howto constrain the basement of pre-lining is a urgent problem. Taking Hongliangying tunnel as the study subject,first of all,the constraints of the basement could improve the pre-lining structure safety degree,it was verified by numerical simulation method,and the lock foot mini-piles were selected for strengthening the basement. Then based on the bearing mechanismof piles foundation,the force of pile was identified by stiffness distribution method,and the optimumsetting angle of mini-piles and spacing of piles were determined. The research results showthat strengthen the constraints of the basement can improve the pre-built arch structure security coefficient of the arch waist and crown,reduce the arch crown settlement. T76 S pile can meet the requirements.When the angle between the piles and the vertical direction in the range of 20° ～ 45°,the force of pile is the most reasonable.
出处
《铁道建筑》
北大核心
2016年第3期75-78,共4页
Railway Engineering
基金
国家科技支撑计划(2013BAF078B06)
关键词
预切槽法
黄土隧道
锁脚
微型桩
刚度分配
Precutting method
Loess tunnel
Lock foot
Mini-piles
Stiffness distribution method
作者简介
王新东（1979-），男，高级工程师。
