软弱围岩大断面隧道掌子面锚杆加固参数研究

软弱围岩隧道的开挖施工容易造成开挖面失稳坍塌以及拱顶沉降过大等事故,须对围岩和掌子面进行加固,以保证施工安全。以宁波象山县野猪山隧道为工程背景,以新意法为理论基础,采用玻璃纤维锚杆加固隧道掌子面,通过数值分析研究了掌子面锚杆布置密度、加固长度、搭接长度等加固参数,得出掌子面玻璃纤维锚杆加固长度应大于隧道开挖直径,可提高掌子面的稳定性;对掌子面挤出变形控制较为严格的情况下,可以对全断面布置锚杆进行加固。

Study on Bolt of Face Rock for Large Cross-section Tunnel in Weak Surrounding Rock

The excavation of soft surrounding rock tunnel is easy to cause the instability of excavation face and large ground settlement and it is necessary to ensure the construction safety by reinforcement the surrounding rock and tunnel face.In this paper,taking Yezhushan tunnel in Xiangshan country of Ningbo city as the engineering background,using ADECO-RS as the theoretical basis,and glass fiber bolts to reinforce the tunnel face,the parameters of tunnel face reinforcement such as laying density of the bolt,the reinforcement length of bolt and the lap length,are obtained by finite element analysis and theoretical analysis.It is found that,the length of the reinforcement of the glass fiber anchor of the face should be greater than the tunnel excavation diameter,which can improve the stability of the surface,and in the case of tightening control of the extrusion of the face,it is possible to reinforce the whole section of the anchor.The conclusions can be used as references for soft rock tunnel construction.