4线车站浅埋隧道施工过程中锚杆受力特性研究

Research on Mechanical Characteristics of Anchor Bolts of Shallow-buried Four-Track Railway Station Tunnel

针对大跨大断面隧道,若按传统设计,锚杆长度及环、纵向间距等参数沿拱墙范围不变,势必产生浪费,增加成本。为了解特大跨大断面浅埋隧道分部开挖施工过程中锚杆的受力变化特征及各部位最终受力状态,以六(盘水)沾(益)铁路乌蒙山2号4线车站隧道工程为背景,采用数值模拟和现场测试方法,开展分部开挖系统锚杆轴力分布特点研究。研究结果表明:1)锚杆受力大小与部位相关,不同部位的锚杆轴力差异显著,边墙部位锚杆轴力>拱肩部位锚杆轴力>拱顶部位锚杆轴力。2)基于锚杆受力特征可知,系统锚杆可采用不等参支护。3)大跨大断面隧道采用系统锚杆不等参支护,既经济又可节省工程建设时间。

In conventional design,anchor bolt spacing and length are invariable along the arch wall of a large-span and large cross-section tunnel,increasing cost and causing waste.Numerical simulations and site monitoring are used to study the stress variation characteristics of anchor bolts and the final stress state of each part during partial excavation of a shallow-buried four-track railway station tunnel on Liupanshui-Zhanyi railway with a large span and large cross-section,as well as the characteristics of axial force distribution of systematic anchor bolts.The following conclusions are drawn:(1)the axial force of a systematic anchor bolt varies with its location,and the axial force of a systematic anchor bolt is the greatest at the sidewall,followed by the arch shoulder,and the smallest at the crown;(2)inequable support parameters can be used according to the characteristics of axial force of a bolt;(3)the use of inequable support parameters in a large-span and large cross-section tunnel can help in reducing cost and construction time.