Abstract: The influence of shaft use on the strength of shaft concrete is slow and continuous. There is no mature theory and technical specification for inclined shaft freezing technology in China. In this paper, the ultrasonic rebound comprehensive method widely used at this stage is adopted to check and test the compressive strength of the shaft wall, and it is found that the current strength of the shaft wall and floor concrete is lower than the designed value (or the initial value), which is not conducive to long-term safe operation and provides reliable basis for the evaluation of shaft safety state.

Key words: ultrasonic, auxiliary inclined shaft, frozen section wall, compressive strength, ultrasonic rebound detection