软岩下桥隧相连段车辆冲击效应模型试验研究

为研究软弱围岩（Ⅳ、Ⅴ级）条件下桥、隧相连段在后期运营中车辆荷载及其冲击作用下的力学行为、作用效应等，依托相关工程实例开展了系统的室内模型试验研究。结合桥、隧相连工程的实际特点，依据相似理论，给出了模型试验中桥、隧结构及洞周岩土体各物理量间的相似关系，对模型试验方法进行了系统的分析和阐述。通过模型试验研究表明，Ⅳ、Ⅴ级围岩条件下的桥、隧相连段中，运营中的汽车荷载及其冲击作用，易使桥梁、隧道衬砌关键部位产生不利力学效应或结构损伤，使桥梁跨中、搭接端及洞底产生过大位移或沉降，并易使隧道洞口围岩稳定性降低等。因此，对桥隧相连段的桥、隧及洞口围岩各关键部位宜采取局部加强措施，以避免各种损伤或病害的发生

Study of model test of vehicle impact effects on bridge and tunnel connected project in weak surrounding rock

In order to investigate the mechanical and deformation characteristics or action effects caused by vehicles and impacts on important parts of bridge or tunnel connecting sections under weak surrounding rocks especially grade Ⅳ or Ⅴ surrounding rocks,systematical indoor model tests have been carried out.The relationship among physical quantities and the similarity indexes have been worked out under the dimensional analysis method of the similarity theorem considering the characteristics of bridge and tunnel connecting projects.The model test methods such as test contents,working conditions,test equipments and instruments etc.,have been systematically analyzed and elaborated.Through analyzing the test phenomena and results,some conclusions are drawn as follows: the vehicle loads with impact actions during post operation stage cause harmful mechanical effects or structure damages on some key parts of bridge or tunnel,such as oversize displacement on bridge mid-span and lap joint tip or oversize settlement of tunnel bottom,or lower stability of surrounding rocks nearby tunnel entrance etc.Consequently,for bridge and tunnel connecting projects under Ⅳ or Ⅴ surrounding rocks,some key parts of bridge,tunnel lining and surrounding rocks nearby the entrance should be strengthened in order to avoid damages or diseases.