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在混凝土结构中,其应力状态随着荷载、温度等条件的不同会发生相应的变化。对混凝土结构中裂缝深度的无损检测,必须考虑裂缝面的应力状况,特别是深裂缝,其裂缝面上应力状况的影响则更加显著。利用大型混凝土块试验,比较在不同应力条件下,几种代表性的无损检测方法的测试结果。结果表明:当裂缝面上承受微小压应力时,“相位反转法”和“传播时间差法”均不能正确地测试裂缝深度;而当裂缝面上的压应力超过5 MPa时,现目前使用的检测方法都无法合理地测出裂缝的深度。因此,在检测裂缝深度时,需要密切关注裂缝面上的应力状态,同时,通过“表面波法”得到的裂缝深度测试结果的变化,间接地推测裂缝面上应力状态,为结构的分析提供相应依据。
In concrete structures, the stress state changes with the load, temperature and other conditions will change accordingly. For non-destructive testing of crack depth in concrete structures, the stress state of the fracture surface must be considered, especially for deep fractures. The influence of stress conditions on the fracture surface is more significant. The test results of several representative non-destructive testing methods are compared under different stress conditions by using large concrete block test. The results show that when the compressive stress on the fracture surface is small, both the “phase inversion method” and the “propagation time difference method” can not correctly test the fracture depth. When the compressive stress on the fracture surface exceeds 5 MPa, Now the detection methods used are not able to reasonably measure the depth of cracks. Therefore, it is necessary to pay close attention to the stress state on the fracture surface when detecting the fracture depth. At the same time, the stress state on the fracture surface is indirectly estimated by the change of the fracture depth test results obtained by the Surface Wave Method, and the structural analysis Provide the appropriate basis.