销钉锚固后CRTSⅡ型板宽窄接缝损伤及锚固方案优化研究

Damage of Wide and Narrow Joints of CRTS II Slab After Pin Anchorage and Optimization of Anchorage Scheme

CRTSⅡ型板上拱主要采用销钉锚固进行整治,但缺乏完善的整治理论,为此基于混凝土塑性损伤理论和内聚力理论研究锚固后宽窄接缝的损伤特点,利用有限元模型研究不同锚固方案下轨道板的稳定性和销钉受力,在此基础上提出更优的锚固方案。研究结果表明:销钉锚固后窄接缝仍可能完全破损,损伤形式和程度与锚固前相同;同一块板上锚固点的数量对轨道板稳定性和销钉受力影响较小;第1个锚固点离损伤的宽窄接缝越远,轨道板稳定性越差,超过第3根轨枕时,轨道板上拱位移超限,但销钉上拔力可降低40%;同一锚固点销钉数量对轨道板稳定性影响较小,但增加销钉数量可明显改善其受力,销钉数量由1增至3时上拔力降低45%;综合轨道板的稳定性及销钉受力,建议在损伤的宽窄接缝附近第2根轨枕处用3根销钉进行锚固。

CRTSⅡslab arch is mainly maintained by pin anchorage,but there is a lack of perfect maintenance theory.Therefore,based on the concrete plastic damage theory and cohesion theory,the characteristics of damage of the wide and narrow joints after anchorage are studied,and the stability of the track slab and the force on the pin under different anchorage schemes are studied by using the finite element model.On this basis,a better anchorage scheme is proposed.The results show that:Narrow joints may still be completely damaged after the pin is anchored,and the damage form and degree are the same as before;the number of anchorage points on the same slab has little effect on the stability of the track slab and the force on the pin;the farther the first anchorage point is from the damaged wide and narrow joints,the poorer the stability of the track slab,and when the third sleeper is surpassed,the arch displacement of the track slab exceeds the limit,but the uplift force of the pin may decrease by 40%;although the number of pins at the same anchorage point has little effect on the stability of the track slab,increasing the number of pins can significantly improve the force on the pin,and when the number of pins increases from 1 to 3,the uplift force decreases by 45%;considering the stability of the track slab and the force on the pin,it is recommended to use 3 pins for anchorage at the second sleeper near the damaged wide and narrow joints.