盾构隧道管片混凝土-加固体界面高温后拉伸性能试验

Experimental Study of Tensile Properties of Interface between Shield Segment Concrete and Reinforcement Structure after Exposure to High Temperature

借助火灾试验,对盾构隧道管片混凝土-加固体界面经历高温后的拉伸性能进行研究。试验温度等级为50、100、200、250、300℃,试验测试高温后盾构隧道管片混凝土-加固体界面的破坏形式、荷载-位移关系及温度-破坏荷载。试验结果表明:1)高温后混凝土-加固体界面拉伸破坏形式分为Ⅰ型破坏和Ⅱ型破坏2种,较低温度(20、50、100、200℃)下主要发生Ⅰ型破坏,较高温度(250℃和300℃)下主要发生Ⅱ型破坏。2)混凝土-加固体界面的抗拉刚度随温度升高而降低,在较低温度和较高温度下,影响混凝土-复合腔体界面抗拉强度的主要因素分别是混凝土的抗拉强度和混凝土-复合腔体粘结界面的抗拉刚度。

The mechanical behaviors of the combined system consisting of shield tunnel segment and reinforcementstructure during and after fire scenarios are analyzed by the means of experiment. The experiments are conducted under50 ℃, 100 ℃, 200 ℃, 250 ℃ and 300 ℃ to test the failure modes of the interface, the relationship between load anddisplacement and the temperature damage load. The experimental results indicate that： 1） The failure of the interfacebetween the C50 concrete cube and the composite structure can be divided into 2 types. Failure mode 1 occurs underrelatively low temperature （20 ℃, 50 ℃, 100 ℃ and 200 ℃） and mode 2 occurs under relatively high temperature（250 ℃ and 300 ℃）. 2） The tensile stiffness of the interface reduces with the temperature increase; the major factorsaffecting the tensile properties of the interface after exposure to relatively low temperature （20 ℃, 50 ℃, 100 ℃ and200 ℃） and relatively high temperature （250 ℃ and 300 ℃） is the tensile strength of the concrete and the bondproperty between the binder and the concrete respectively.