| 整体桥H型钢-RC阶梯桩与土相互作用拟静力试验 |
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| 引用本文： | 庄一舟,宋琨生,宋永青,陈国栋,黄福云,陈良.整体桥H型钢-RC阶梯桩与土相互作用拟静力试验[J].交通运输工程学报,2022,22(5):145-162. |
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| 作者姓名： | 庄一舟 宋琨生 宋永青 陈国栋 黄福云 陈良 |
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| 作者单位： | 1.浙江工业大学 土木工程学院，浙江 杭州 3100142.福州大学 土木工程学院，福建 福州 350108 |
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| 基金项目： | 国家自然科学基金项目51778147 |
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| 摘 要： | 以H型钢-RC阶梯桩模型试验为背景，进行了2根H型钢-RC阶梯桩(HS-RC-0.25、HS-RC-0.50)及1根H型钢桩(HS)的低周往复荷载拟静力试验；在桩顶施加水平位移荷载，埋设应变片与土压力计，采用特殊设计的桩身水平变位测试方法，得到了H型钢-RC阶梯桩桩身破坏特点、沿桩深方向的桩身水平位移与应变、骨架曲线和滞回性能曲线；利用OpenSEES对比分析了桩顶自由与固定条件下阶梯桩桩顶水平变位能力，得到了阶梯桩水平承载力折减系数与转化系数，对比了利用折减系数得到的模型桩水平承载力计算值与试验值。试验结果表明:H型钢桩的桩顶弹性变形为2~25 mm，其水平变形能力强，承载能力好，加载全过程滞回环饱满，耗能效果好；刚度比对阶梯桩的破坏模式无显著影响，阶梯桩的上段钢桩均无明显的屈曲破坏，变截面处混凝土严重剥落且破坏位置相同；随刚度比增大，阶梯桩-土体系屈服位移及屈服荷载均提高，HS-RC-0.25较HS-RC-0.50桩顶屈服位移减小了29.15%，桩身应变突变减小；阶梯桩的滞回环在加载初期因为滑移表现为捏拢状，而在加载后期过渡为饱满的梭形，耗能效果良好，HS-RC-0.50加载全过程的耗能比HS-RC-0.25多25.4%，具有较好的水平变形能力；对比试验值，HS-RC-0.25的计算误差为-9.68%，HS-RC-0.50的计算误差为-2.47%。可见，HS-RC阶梯桩能满足整体桥桩基的水平变形需求，利用折减系数能较好地计算阶梯桩的水平承载力特征值。
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| 关 键 词： | 桥梁工程 整体桥 H型钢桩 H型钢-RC阶梯桩 桩与土相互作用 拟静力试验 有限元分析 |
| 收稿时间： | 2022-04-17 |
Quasi-static test on H-shaped steel-RC stepped pile-soil interaction of integral bridge |
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| ZHUANG Yi-zhou,SONG Kun-sheng,SONG Yong-qing,CHEN Guo-dong,HUANG Fu-yun,CHEN Liang.Quasi-static test on H-shaped steel-RC stepped pile-soil interaction of integral bridge[J].Journal of Traffic and Transportation Engineering,2022,22(5):145-162. |
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| Authors: | ZHUANG Yi-zhou SONG Kun-sheng SONG Yong-qing CHEN Guo-dong HUANG Fu-yun CHEN Liang |
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| Affiliation: | 1.College of Civil Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, China2.College of Civil Engineering, Fuzhou University, Fuzhou 350108, Fujian, China |
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| Abstract: | On the basis of H-shaped steel-RC stepped pile model tests, the quasi-static tests of 2 H-shaped steel-RC stepped piles (HS-RC-0.25, HS-RC-0.50) and an H-shaped steel (HS) pile under the low cyclic repeated loading were carried out. A horizontal displacement load was applied on the pile top, and the strain and soil pressure gauges were embedded, a specially designed test method for the horizontal displacement of the pile body was adopted, and the failure characteristics of the HS-RC stepped pile, the horizontal displacement and strain of the pile body along the pile depth, skeleton curve, and hysteretic behavior curve were obtained. The horizontal displacement abilities of the stepped pile top under free and fixed conditions were compared and analyzed by OpenSEES. The reduction coefficient and conversion coefficient of the horizontal bearing capacity of the stepped pile were obtained, and the calculated value obtained by the reduction coefficient and test value of horizontal bearing capacity of the model pile were compared. Test results show that the elastic deformation range of the pile top of the HS pile is 2-25 mm, and the pile has strong horizontal deformation ability, positive bearing capacity, full hysteresis loop during the whole loading process, and excellent energy consumption effect. The stiffness ratio has no significant effect on the failure mode of the stepped pile. The upper steel pile of the stepped pile has no apparent buckling failure, and the concrete at the variable section is seriously peeled off with the same failure position. With the increase in the stiffness ratio, the yield displacement and yield load of the stepped pile-soil system increase. Compared with that of HS-RC-0.50, the yield displacement of HS-RC-0.25 decreases by 29.15%, and the strain mutation of the pile body decreases. The hysteresis loop of the stepped pile is pinched at the initial loading stage due to slip and becomes spindle-shaped at the later loading stage. The energy consumption effect is positive, and the energy consumption of HS-RC-0.50 during the whole loading process is 25.4% more than that of HS-RC-0.25, which shows an excellent horizontal deformation ability. Compared with the experimental value, the calculation error of HS-RC-0.25 is -9.68%, while the calculation error of HS-RC-0.50 is -2.47%. The HS-RC stepped pile can meet the horizontal deformation requirements of the integral abutment bridge pile foundation, and the reduction coefficient can be used to better calculate the stepped pile's horizontal bearing capacity characteristic value. |
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