| UHPC加固盾构隧道衬砌结构试验 |
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| 引用本文： | 柳献,张姣龙,蒋子捷,刘震,徐品,李飞.UHPC加固盾构隧道衬砌结构试验[J].中国公路学报,2021,34(8):181-190. |
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| 作者姓名： | 柳献 张姣龙 蒋子捷 刘震 徐品 李飞 |
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| 作者单位： | 1. 同济大学 土木工程学院, 上海 200092;2. 上海复培新材料科技有限公司, 上海 201804 |
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| 基金项目： | 国家自然科学基金项目（51578409）；国家自然科学基金青年科学基金项目（51908424）；上海市浦江人才计划项目（19PJ1409700） |
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| 摘 要： | 为了研究超高性能混凝土（UHPC）加固盾构隧道衬砌结构性能，首先开展了UHPC材料抗压、抗拉试验研究，然后将其应用于加固盾构隧道衬砌结构，并开展了加固结构的极限承载力足尺试验研究。该加固方法包括以下步骤：在隧道管片内表面进行凿毛处理，在凿毛后的内弧面植入弯筋和化学锚栓，清理凿毛表面，最后在内弧面浇筑0.06 m厚UHPC。未加固衬砌结构整环外径6.2 m，环宽0.6 m，管片厚度0.35 m。加固结构通过外弧面上均匀分布的24个千斤顶进行加载，这些千斤顶分为3组，分别控制其荷载大小，以模拟地层的不均匀压力。标准养护条件下，UHPC18 d龄期（足尺试验龄期）的抗压和抗拉弹性极限强度分别达到138 MPa和12 MPa。加固整环结构的弹性极限由腰部外弧面的混凝土开裂控制，结构破坏是由于原管片接头位置出现4个塑性铰，致使结构变成可变机构。通过分析试验结果以及对比现有加固技术，得到如下主要结论：①UHPC材料的拉压力学性能对养护湿度的依赖性较小，材料存在明显的应变强化现象；②UHPC加固隧道衬砌结构极限承载力由管片接头部位性能控制；③UHPC自身的材料性能得到充分利用，但原隧道管片的材料性能尚未得到充分发挥；④相比未加固结构，初始结构刚度提高1个数量级，结构弹性极限提高了115%，UHPC加固结构承载力和传统的钢板加固相当。
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| 关 键 词： | 隧道工程 盾构隧道结构加固 足尺试验 超高性能混凝土 极限承载力 |
| 收稿时间： | 2020-07-07 |
Experimental Investigations of a Segmental Tunnel Ring Strengthened by Using UHPC |
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| LIU Xian,ZHANG Jiao-Long,JIANG Zi-jie,LIU Zhen,XU Pin,LI Fei.Experimental Investigations of a Segmental Tunnel Ring Strengthened by Using UHPC[J].China Journal of Highway and Transport,2021,34(8):181-190. |
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| Authors: | LIU Xian ZHANG Jiao-Long JIANG Zi-jie LIU Zhen XU Pin LI Fei |
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| Affiliation: | 1. Department of Geotechnical Engineering, Tongji University, Shanghai 200092, China;2. FODEV Technology Co. Ltd., Shanghai 201804, China |
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| Abstract: | In order to investigate structural behavior of segmental tunnel rings strengthened by making use of ultra-high performance concrete (UHPC), compressive and tensile tests on the material of UHPC were carried out, followed by a bearing-capacity test on a real-scale segmental tunnel ring strengthened by using UHPC. The strengthening technique consisted of the following steps:roughening the inner surface of the tunnel segments, embedding curved rebars and chemical anchor bolts into the segments, cleaning the roughened surface, and casting UHPC with a thickness of 0.06 m. The outer diameter of the unstrengthened segmental runnel ring was equal to 6.2 m. Its width and thickness amounted to 0.6 m and 0.35 m, respectively. The strengthened ring was loaded by means of 24 hydraulic jacks that were equally spaced along the outer circumference of the ring. These jacks were subdivided into three groups, the forces of which were controlled separately, thereby simulating the anisotropic ground pressure. The bearing-capacity test of the real-scale segmental tunnel ring was carried out 18 days after strengthening. On that day, the compressive strength and tensile elastic limit of the UHPC under standard curing conditions, amounted to 138 MPa and 12 MPa, respectively. The elastic limit of the strengthened ring was associated with cracking of the concrete at the outer surface in the lateral regions. The structural failure was associated with four plastic hinges that developed at the joints between neighboring segments, resulting in the development of a kinematic mechanism. The main conclusions drawn from the analysis of the experimental results and a comparison of existing strengthening techniques are as follows:① The material properties of the UHPC, characterized by strain hardening, are independent of the curing humidity. ② The bearing capacity of the strengthened tunnel ring is governed by the local behavior of the joints between neighboring segments. ③ The material properties of the UHPC are fully utilized, whereas the reinforcement and the concrete in compression are not. ④ The use of UHPC results in an increase of the initial structural stiffness of the unstrengthened ring by one order of magnitude and its elastic limit by 115%. The bearing capacity of the ring strengthened by using UHPC is comparable to that of the rings strengthened by means of traditional strengthening techniques, such as using steel rings. |
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| Keywords: | tunnel engineering strengthening of segmental tunnel ring real-scale test ultra-high performance concrete bearing capacity |
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