Abstract: Comparison of the displacements and bearing capacity of these two cross section types were performed by using finite element method with ABAQUS． The surrounding rock and anchorage were simulated by 8-node 3D brick elements． Interface between the surrounding rock and anchorage was modeled by contact element． A extended Mohr-Coulomb model was adopted for the rock mass． Over-loading method was applied to calculate the ultimate bearing capacity of anchorage． The results show that for U-type cross section，stress concentration occurs at the arch，while the stress distribution around the circular cross section is uniform． In case of identical section area and cable force，the displacement of circular tunnel anchorage is less than U-type tunnel anchorage by 22%． The ultimate bearing capacity of circular anchorage is larger than U-type anchorage by 18%．

Key words: suspension bridge, tunnel anchorage, cross section type, finite element method, ultimate bearing capacity

摘要： 应用有限元软件ABAQUS对比分析了马蹄形和圆形两种横断面隧道式锚碇的承载性能。围岩及锚碇采用实体 单元模拟，围岩与锚碇之间设置接触面单元;围岩采用扩展的Mohr-Coulomb屈服模型;使用超载法分析锚碇的极限承 载能力。计算结果表明:马蹄形断面在边墙与拱以及边墙与底板的交界处出现较大应力集中，圆形断面应力分布均 匀;在断面面积相等的情况下，相同缆力作用下圆形断面锚碇位移小于马蹄形锚碇约22%，极限承载力高出马蹄形锚 碇约18%，说明圆形断面承载性能优于马蹄形断面。

关键词: 悬索桥, 隧道式锚碇, 横断面形状, 数值模拟, 极限承载力