拱形空腔预应力锚块优化

Optimization of arch cavity prestressed anchor block

针对预应力闸墩锚块矩形空腔表面应力过大问题，结合拱结构受力性能，提出了拱形空腔预应力锚块结构形式，运用ABAQUS软件针对5种不同起拱高度模型进行了计算，得到了闸墩颈部、锚块空腔表面竖向及横河向应力．对闸墩颈部、锚块空腔表面应力进行了对比分析．结果表明，与矩形空腔锚块相比，当采用拱形空腔锚块时可以有效降低闸墩颈部及空腔表面应力，当起拱高度为1／10～1／7跨度时，效果尤为明显；对拉锚比进行了优化研究，结果表明，当拱形空腔采用拉锚比为1．7时，与矩形空腔采用拉锚比为1．815时应力结果相当，说明采用拱形空腔预应力锚块结构形式可以降低预应力锚索用量，从而取得明显的经济效益．

An arch cavity prestressed anchor block structure form combining with mechanics properties of the arch structure is proposed, in light of the problem of excessive stress of rectangular prestressed anchor block cavity surface. Five models of different arch height were calculated using software ABAQUS; and then vertical and horizontal stresses of pier neck and anchor block cavity surface are obtained. Stress of the pier neck and that of anchor block cavity surface are compared and analyzed. The results show that using arch-shaped cavity anchor block can effectively reduce the stresses of the pier neck and the cavity surface, compared with the rectangular cavity anchor block. When the arch height is 1/10-1/7 of span, the effect is particularly evident. The research results of optimized pull-anchor coefficient shows that the stress result of arch-shaped cavity with pull-anchor coefficient ratio of 1.7 is equivalent to that of the rectangular cavity with pull-anchor coefficient of 1. 815; so it is indicated that use of arch-shaped cavity prestressed anchor block structure can reduce the amount of prestressed anchor cables, so as to obtain significant economic benefits.