软岩地区悬索桥隧道锚设计研究

Research on the Design of Tunnel-type Anchorage of Suspension Bridge in Soft Rock Area

研究目的:重庆几江长江大桥采用地锚式悬索桥,北岸隧道式锚碇位于软岩地区,在软岩地区建造隧道锚可供参考的资料和研究成果较少。本文通过对该隧道锚进行数值分析、现场缩尺模型试验、稳定性加强措施等一系列研究,掌握软岩地区隧道锚与围岩系统的破坏模式和变形机制,以期为软岩地区隧道锚的设计提供技术支持。研究结论:(1)数值分析表明,7倍设计荷载是锚体位移的一个突变点,即隧道锚稳定安全系数不小于7;(2)通过1∶10现场缩尺试验,8倍设计荷载为锚体的屈服荷载,试验成果与数值分析结果基本一致;(3)通过设置剪力块、加劲工字钢架等措施,隧道锚的整体抗剪强度由7.0提高到9.0;(4)本研究成果可为软岩地区悬索桥隧道锚设计提供参考和借鉴。

Research purposes:Jijiang Changjiang river bridge in Chongqing is a suspension bridge which used the tunnel-type anchorage in soft rock area in the northern bank.However,there are fewer references and research results for the construction of tunnel-type anchors in soft rock areas.Through the numerical simulation analysis on the tunneltype anchorage,scale model test and strengthen measures research,the failure mode and deformation mechanism of tunnel-type anchorage and surrounding rock system in soft rock area are mastered,to provide technical support in the design of tunnel-type anchorage in soft rock area.Research conclusions:(1)Numerical analysis shows that the 7 times design load is a sudden change point of anchorage displacement,that is,the safety factor of tunnel-type anchorage stability is not less than 7.(2)Through 1∶10 field scale test,8 times design load is the yield load of anchor body,which is basically consistent with the numerical results.(3)The overall shear strength of tunnel-type anchor is increased from 7.0 to 9.0 by the measure of setting shear blocks,stiffening I-beam,etc.(4)The research results can provide reference for tunnel-type anchor design of suspension bridge in soft rock area.