预应力锚索荷载分布机理原位试验研究

根据悬索桥隧道式锚碇系统预应力岩锚原位试验及数值模拟结果,分析了锚固长度、自由长度、注浆性质以及锚注体与围岩接触方式对岩锚极限抗拔力和破坏形态的影响。阐释了锚索的根状效应和围岩应力场分布形态,提出安全储备系数概念。研究结果表明,极限抗拔力的提高主要依赖于上述参数综合作用。自由长度对围岩有效传递和分散围岩应力有关键作用,和锚固长度共同控制岩锚的破坏形态;在锚碇系统中,和初始预应力一起确定了岩锚参与荷载分担的贡献值和时机。

FIELD TESTING STUDY ON LOAD DISTRIBUTION MECHANISM OF PRESTRESSED ANCHORAGE CABLE

Based on field testing results and numerical simulation of prestressed anchor cable of tunnel anchorage system of suspension bridge,the ultimate anti-pulling capacity and failure mode affected by anchor-length,free- length,grouting quality and interface mode between grout-cable and rock mass are analyzed. Stress distribution modality in rock mass and root effect are also introduced. And the concept of safety storage coefficient is put forward. It indicates that the increase of ultimate anti-pulling capacity increase principally depends on synthetical functions of the variables mentioned above. Free-length has key effect on effectively transferring and dispersing stress to wall rock. The failure mode of anchor cable is controlled by free and anchor length. The contribution value and occasion of anchor cable are determined by its free-length and initial stress.