锚碇–围岩系统在拉剪复合应力条件下的变形规律及破坏机制研究——以坝陵河特大岩锚悬索桥为例

STUDY ON DEFORMATION LAW AND FAILURE MECHANISM OF ANCHORAGE-SURROUNDING ROCK SYSTEM UNDER TENSILE-SHEAR COMPLEX STRESSES——TAKING SUPER-LARGE SUSPENSION BRIDGE ON BALING RIVER FOR EXAMPLE

锚碇基础是悬索桥的关键受力部位,认识它的变形规律和破坏机制是评价其强度和稳定性的前提。岩体现场缩尺拉拔模型试验发现,锚碇后锚面上,围岩位移呈马鞍形分布,残余变形率呈V形分布;侧壁围岩位移呈倒塞体形分布,永久变形比例高。FLAC3D数值模拟发现,应力场分布具有明显的分段特征,前段和后段锚体围岩有着不同的应力传递路径;塑性变形主要发生在锚体周边及上部岩体中,破坏形态类似塞体状;围岩–锚碇系统可能发生整体拉剪复合破坏。设计和施工过程中,应对塑性区及显著变形区内的岩体进行重点加固。

Anchor basement is the key bearing component of suspension bridge;and its deformation and failure mechanism is the foundation of strength and stability evaluation.Several facts are found through the in-situ pull model test.The total displacement and the rate of residual displacement on the back anchor face show saddle and V-shaped distribution,respectively.The displacement of the surrounding rock on the flank appears plug-style distribution,and the rate of the permanent deformation is high.According to the numerical model test to be by fast Lagrangian analysis of continuum in 3D（FLAC^3D）,some conclusions are also drawn：（1） the stress field shows subsection character,and the stress transfer route between fore part and back part of the anchor body is different;（2） the plastic zones which appear plug-style are mainly found beside the anchor and in the upper rock mass;（3） tensile-shear complex failure maybe happen in the rock-anchor system.The plastic zones and the prominent deformation zones in the rock mass should be paid more attention during design and construction.