计算机层析成像技术(Computer Tomograghy)简称CT,是一项快速发展的现代无损检测技术。CT因分辨率高,能准确反映探测对象的细部结构,可用于对隐蔽结构工程的缺陷和细微地质构造进行准确精细检测。本文以超声波CT技术为例简述了将该项技术应用于地下隐蔽工程检测的理论框架和工程技术要点,以大型灌注桩基础的桩端注浆质量检测和地下群桩穿孔位置检测等实际工程实例说明在工程中联合应用各种CT检测技术的方法。这两项检测实例来源于长江大桥和跨海大桥的超大型群桩基础,是在国际上首次完成的地下120米深度桩基础灌浆效果检测和成桩质量检验的实例。 Computer tomography (Computer Tomograghy) referred to as CT, is a rapidly developing modern non-destructive testing technology. Due to its high resolution, CT can accurately reflect the detail structure of the detection object and can be used to accurately and finely detect the defects and the subtle geological structures of the hidden structural engineering. In this paper, the ultrasonic CT technology as an example to briefly describe the application of this technology to detect the hidden underground engineering theoretical framework and engineering techniques to large-scale injection pile foundation grouting based on the quality inspection and detection of underground pile groups perforation location and other practical engineering Examples illustrate the method of joint application of various CT detection techniques in engineering. The two test cases originated from the super-large group pile foundation of the Yangtze River Bridge and the Sea-Crossing Bridge. It is the first time in the world to complete the test of grouting effect and pile quality inspection of the pile foundation under the depth of 120 meters.