软弱围岩中桥隧搭接多源损伤影响因素分析

对软弱围岩(Ⅳ和Ⅴ级)中的桥隧搭接工程进行了室内模型试验研究和影响因素分析。研究结果表明:桥隧搭接工程在其施工及运营中的力学行为及多源损伤情况受围岩等级、桥梁跨径及基础形式、搭接长度、汽车荷载等级及汽车冲击等的影响,长期状态下易导致桥梁、隧道衬砌各关键部位的结构损伤,对桥梁结构、隧道衬砌、桥台与桩基础的耐久性以及洞口围岩的稳定性不利;为防止桥、隧各关键部位因不利作用而损伤甚至破坏,避免洞口围岩出现失稳、坍塌及滑坡等病害,应对桥、隧及围岩关键部位局部加强,且宜采用桩基础、减小桥梁跨径、加大搭接长度、减小汽车荷载及其冲击影响。

Influence factors analysis on multiple source damages of bridge and tunnel lap joint project in weak surrounding rock

Indoor model tests and influence factors analysis were carried out on bridge and tunnel lap joint project in weak surrounding rocks(grade Ⅳ or Ⅴ).The results show that:The mechanical behaviors and multiple source damages during the construction and post operation stage can be influenced by surrounding rock grade,bridge span and foundation style,length of lap joint period,vehicle loads and impacts etc.,which for the long run,may not only cause structure damages of bridge or tunnel key parts,but also do harm to the durability of bridge,tunnel lining,abutment and its pile foundation or the stability of surrounding rocks nearby the tunnel entrance.In order to avoid the damages or even destructions due to various kinds of harmful effects,and decrease or reduce the oversize settlement of side or upper slopes nearby the entrance and the occurrence of instability,collapse or slide of slope,some key parts of bridge,tunnel lining and rocks or side and upper slopes nearby the entrance should be strengthened,along with the adoption of pile foundation,the reduction of bridge span,the lengthening of lap joint period,the avoidance of oversize vehicle loads and impacts etc.