In order to promote the industrial production of utility tunnel, based on the actual prefabricated utility tunnel engineering background, two types of precast L‐shaped joint with end boundary elements are experimentally studied. In this paper, two precast L‐shaped top plates with the haunch zone and two precast L‐shaped bottom plates without haunch zone were designed. These two types of specimen were tested to investigate the mechanical performance of precast L‐shaped joint under different load combination effects. There were no obvious phenomenon in the whole opening test, and the most unfavorable load combination was in the elastic stage. In the closed test, the average ultimate bearing capacity of the prefabricated top and bottom plant specimens decreased by 2% and 1%, respectively, compared with the cast‐in‐place specimens, and the average ductility coefficients of the top and bottom plates are 5.78 and 2.73, respectively. It is also found that the setting of the haunch zone can improve the bearing capacity. The bending capacity of prefabricated L‐shaped joints calculated by the Chinese code's recommended formula is conservative, and the ratio of the test value to the calculated value is about 1.5. Finally, the reinforcement arrangement of the prefabricated specimens in the closed test was optimized by finite element software. It can be considered that changing the diameter of the reinforcements in the concrete compression zone to 16 mm will not affect the mechanical properties of precast joints.

中文翻译：

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预制公用隧道L形节点的力学性能试验及有限元分析

为了促进公用事业隧道的工业化生产，在实际的预制公用事业隧道工程背景的基础上，对两种类型的带有端部边界单元的预制L形接头进行了试验研究。在本文中，设计了两个带有腰带区域的预制L形顶板和两个没有腰带区域的预制L形底板。对这两种类型的试样进行了测试，以研究预制L型接头在不同荷载组合作用下的机械性能。在整个开孔试验中没有明显的现象，最不利的载荷组合是在弹性阶段。在封闭测试中，预制的顶部和底部植物标本的平均极限承载力与现浇标本相比分别降低了2％和1％，顶板和底板的平均延性系数分别为5.78和2.73。还发现，腰带区域的设置可以提高承载能力。根据中文规范的推荐公式计算的预制L形节点的抗弯能力是保守的，测试值与计算值之比约为1.5。最后，通过有限元软件对预制试样在封闭试验中的钢筋布置进行了优化。可以认为将混凝土受压区中钢筋的直径更改为16 mm不会影响预制缝的机械性能。根据中文规范的推荐公式计算的预制L形节点的抗弯能力是保守的，测试值与计算值之比约为1.5。最后，通过有限元软件对预制试样在封闭试验中的钢筋布置进行了优化。可以认为将混凝土受压区中钢筋的直径更改为16 mm不会影响预制缝的机械性能。根据中文规范的推荐公式计算的预制L形节点的抗弯能力是保守的，测试值与计算值之比约为1.5。最后，通过有限元软件对预制试样在封闭试验中的钢筋布置进行了优化。可以认为将混凝土受压区中钢筋的直径更改为16 mm不会影响预制缝的机械性能。