提供兴康特大桥反力的隧道锚蠕变试验研究

Creep Test of Tunnel Anchor Providing Reaction Force of Xingkang Bridge

由于鲜有悬索桥隧道锚现场缩尺模型蠕变试验资料可供参考,为获取雅康高速兴康特大桥实桥隧道锚蠕变变形规律,丰富特大悬索桥隧道锚蠕变试验资料,依托兴康特大桥雅安侧岸坡隧道锚工程区特定地质条件,依据弹性力学的相似理论,开展兴康特大桥雅安侧岸坡隧道锚1∶10原位缩尺模型蠕变试验,根据模型锚和围岩体在1.0P、3.5P、7.0P荷载下的蠕变特性,分析模型锚、围岩和界面错动的蠕变全过程规律。结果表明:在1.0P、3.5P、7.0P荷载作用下,锚体最大蠕变量分别为0.62、0.97、1.58 mm,围岩最大蠕变量分别为0.49、0.85、1.38 mm,锚体与围岩错动最大蠕变量分别为0.15、0.64、1.43 mm。在现场原位缩尺试验的基础上,利用FLAC3D有限元软件进行锚碇与围岩体相互作用的3维黏弹塑性数值分析,从现场实测值与数值分析结果的对比可知,兴康特大桥雅安侧岸坡隧道锚锚碇与围岩现场实测蠕变变形量和计算结果变形发展趋势基本一致,量值相当。雅康高速兴康特大桥在隧道锚和围岩在各级荷载作用下属于稳定型蠕变,锚碇和围压的蠕变不会影响悬索桥的长期稳定性。试验成果在为兴康特大桥隧道锚系统可靠性评价提供有力依据的同时,也为类似工程设计提供了参考。

There are few in-situ creep test data of tunnel anchor for suspension bridge.To obtain the creep deformation law of tunnel anchor of Xingkang Bridge on Yakang Expressway and enrich creep test data of tunnel anchor of super-large suspension bridge,creep tests of 1∶10 in-situ shrinkage model of the Ya’an side slope tunnel anchor of Xingkang Bridge were carried out,based on the specific geological conditions in the Ya’an side slope tunnel anchorage area of Xingkang Bridge and the similar theory of elastic mechanics.According to the creep characteristics of the model anchor and surrounding rock mass under 1.0 P,3.5 P and 7.0 P loads,the whole creep process of the model anchor,surrounding rock and interfacial dislocation were analyzed.The results show that under 1.0 P,3.5 P and 7.0 P loads,the maximum creep deformation of anchor body was0.62 mm,0.97 mm and 1.58 mm,the maximum creep deformation of surrounding rock was 0.49 mm,0.85 mm and 1.38 mm,and the maximum creep deformation of anchor body and surrounding rock was 0.15 mm,0.64 mm and 1.43 mm,respectively.On the basis of in-situ scale tests,the three-dimensional viscoelastic-plastic numerical analysis of the interaction between anchorage and surrounding rock mass was carried out by using FLAC3 D finite element software.The comparison between the field measured values and numerical analysis results shows that the measured creep deformation and calculation results of the anchorage and surrounding rock of the Ya’an side bank slope tunnel of Xingkang Bridge have the similar evolution trends and range of amounts.The creep of tunnel anchorage and surrounding rock mass of Xingkang Bridge on Yakang Expressway belong to stable creep stage under various loads.The long-term stability of suspension bridge was not affected by the creep of anchorage and surrounding rock mass.The test results provide a basis for the reliability evaluation of the tunnel anchorage system of Xingkang Bridge,and also provide a reference for similar engineering designs.