火灾高温后盾构隧道管片-加固体界面粘结性能试验研究

用复合腔体加固体加固隧道结构是一种新型的加固方法,为了掌握火灾高温后复合腔体加固盾构隧道后界面的粘结性能,开展了50~400℃高温处理后粘结剂力学性能试验和混凝土立方体试件-复合腔体界面双面剪切试验。试验结果表明:1)在较低温度条件下,温度升高能优化粘结剂的力学性能;在较高温度下,粘结剂的力学性能随着温度的升高而降低,粘结剂的力学性能在150℃温度条件下最优,在超过300℃温度条件下,力学性能几乎失效。2)高温后混凝土-复合腔体界面破坏形式分为A,B,C3种类型,混凝土-复合腔体界面的剪切刚度随着温度的升高而降低;混凝土-复合腔体界面粘结性能的最佳工作温度TP在50℃左右,完全失效温度Tf为300~400℃,在较低温度(15℃和50℃)、较高温度(100℃和200℃)和高温(250℃~Tf)条件下,影响混凝土-复合腔体界面粘结性能的主要因素分别是混凝土的剪切强度、碳纤维布-钢管界面的粘结性能和混凝土-粘结剂界面的粘结性能。

Experimental Study on Shear Properties of Interface between Segment of Shield Tunnel and New Composite Structure after Exposure to High Temperature

Applying new composite to reinforce the segments of shield tunnel is a new reinforcement method.This paper focuses on the mechanical behavior of the binder and the shear properties of the interface between C50 concrete cube and the new composite structure after exposure to high temperature （50--400 ℃）.The experiment results indicate that：1 ） The mechanical behavior of the binder improves in relatively low temperature condition,however,the mechanical behav-ior of the binder reduces in relatively high temperature condition when the temperature increases;The optimum tempera-ture of the binder is 150 ℃;The binder completely fails after exposure to a temperature over 300 ℃;2）The failure of the interface between the C50 concrete cube and the new composite structure can be divided into 3 types;The optimum temperature Tp of the interface is about 50℃and the failure temperature Tfis between 300℃and 400℃;The shearing stiffness of the interface reduces when the temperature increases;Major factors affecting the shear properties of the inter-face after exposure to relatively low temperature（15,50 ℃）,relatively high temperature（100,200 ℃）and high temper-ature （250 ℃～Tf）include the shear strength of the concrete,the bond property between the CFRP and the steel tube, and the bond property between the binder and the concrete.