| 自由段先注浆对预应力锚索抗拔试验结果影响研究 |
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| 引用本文： | 杨庆光,柳雄,刘杰,何杰,梁凌川,陈斌.自由段先注浆对预应力锚索抗拔试验结果影响研究[J].岩土力学,2020,41(10):3317-3325. |
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| 作者姓名： | 杨庆光 柳雄 刘杰 何杰 梁凌川 陈斌 |
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| 作者单位： | 湖南工业大学 土木工程学院，湖南 株洲 412007 |
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| 基金项目： | 国家自然科学基金（No. 51978260）；湖南省自然科学基金（No. 2020JJ6080，No.2020JJ6007，No.2019JJ60051）。 |
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| 摘 要： | 为了解决无法采用已注浆锚索进行抗拔试验问题，基于界面脱黏剪切模型，利用荷载传递和弹性变形理论，考虑锚索锚固段与自由段长度比Lb /La的影响，建立了采用自由段已注浆锚索抗拔试验结果评价锚索抗拔性能的方法。结果表明：自由段注浆对锚索抗拔力有较大幅度的提高，尤其是当界面剪切阶段由弹性向脱黏过渡时，提高比例快速增加，并在脱黏后逐渐趋于稳定。其次，锚索自由段与锚固段交界面处剪切位移和轴力最大，并向两端逐渐降低。随着拉拔力的提高，界面剪切位移和轴力都不断增大，同时向锚索两端的衰减速度也加快。此外，弹性阶段时剪应力曲线为山峰型，而脱黏阶段为马鞍型，并随抗拔力的提高，马鞍开口逐渐扩大。最后，锚固段与自由段长度比Lb /La对锚索极限抗拔力的影响较小，其极限抗拔力折减系数?Q取值介于0.81～0.83之间，且Lb /La =2.5时，?Q计算值仅比实测结果小6.02%，验证了本文方法的可行性。
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| 关 键 词： | 预应力锚索 自由段先注浆 界面脱黏 抗拔特性 荷载传递 |
| 收稿时间： | 2020-01-14 |
| 修稿时间： | 2020-06-06 |
Influence of the pre-grouting in free segment on the pullout test of prestressed anchor cable |
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| YANG Qing-guang,LIU Xiong,LIU Jie,HE Jie,LIANG Ling-chuan,CHEN Bin.Influence of the pre-grouting in free segment on the pullout test of prestressed anchor cable[J].Rock and Soil Mechanics,2020,41(10):3317-3325. |
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| Authors: | YANG Qing-guang LIU Xiong LIU Jie HE Jie LIANG Ling-chuan CHEN Bin |
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| Institution: | College of Civil Engineering, Hunan University of Technology, Zhuzhou, Hunan 412007, China |
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| Abstract: | To overcome the drawback that the ultimate pullout resistance of prestressed anchor cable cannot be directly obtained by the pullout test, this study proposes a pullout resistance performance evaluation method of pre-stressed anchor cable based on the pullout tests on prestressed anchor cable with pre-grounting in the free segment. Based on the interfacial debonding shear model and the theories of load transfer and elastic deformation, the length ratio of the anchor segment to the free segment was considered in the evaluation method. The results indicate that pre-grouting in free segment can significantly improve the pullout resistance capability of anchor cable. When the interfacial deformation behavior transfers from an elastic manner to debonding stage, the improvement of the pullout resistance will be more pronounced, which will tend to be stable after debonding. The shear displacement and axial force at the interface of the free segment and grouting segment is the highest. With increasing the pullout force, both the shear displacement and axial force increase but the increment declines to the two ends of anchor cable. The shear stress curve is one peak type in the elastic stage and then becomes a saddle type in the debonding stage. The opening of the saddle type curve becomes larger with the improvement of the pullout resistance. Finally, the length ratio of anchoring and free segment has insignificant effects to the ultimate pullout resistance. The reduction coefficient ?Q of the ultimate pullout resistance of pre-grouting anchor cable is in the range from 0.81 to 0.83. The empirical method in paper is feasible due to the fact that merely 6.02% error is existed between the measured ultimate pullout resistance and calculation result when Lb /La is 2.5. |
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| Keywords: | prestressed anchor cable pre-grouting in free segment interfacial debonding pullout resistance feature load transfer |
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