宜昌伍家岗长江大桥隧道锚设计与研究

Design and Study of Tunnel Anchorage for Wujiagang Changjiang River Bridge in Yichang

宜昌伍家岗长江大桥为(290+1160+402)m双塔简支钢箱梁悬索桥,江北侧为国内千米级悬索桥首次在软岩上修建隧道锚。通过地质钻孔、室内试验、斜硐勘探、原位试验等多种方式研究确定合理的岩体力学参数进行隧道锚设计。隧道锚轴线长90 m,其中锚塞体段长45 m,倾斜角度为40°;前锚面尺寸为9.04 m×11.44 m,后锚面尺寸为16 m×20 m。通过室内模型试验和现场缩尺模型试验,结合数值模拟分析掌握隧道锚与围岩的破坏变形模式和流变特征,确定隧道锚的承载力为8P,保证了结构的安全稳定。

The Wujiagang Changjiang River Bridge in Yichang is a two-tower simply-supported steel box girder suspension bridge with three spans of 290,1160 and 402 m.The tunnel anchorage on the north bank of the river is the first anchorage of such type built on soft rocks for a suspension bridge with main span length over 1000 m.Rational mechanical parameters of the rock mass were determined for the tunnel anchorage design via multiple ways,including geological drilling,inclined adit exploration and in-situ test.The axial alignment of tunnel anchorage measures 90 m,the anchor plug is 45 m long and inclines at an angle of 40°.The front and rear anchor surfaces measure 9.04 m×11.44 m and 16 m×20 m,respectively.Indoor model tests and in-situ scale-down model tests were conducted to analyze and examine the failure and deformation modes as well as rheological properties of the tunnel anchorage and surrounding rocks,together with the numerical simulation.The load bearing capacity of the tunnel anchorage is set at 8P,which can ensure the safety and stability of the structure.