Impact response characteristics under different contact relationships between pipe and soil in pipe-jacking construction

In order to study the application of impact image method in the detection of slurry for pipe-jacking construction, different contact relationships between pipe and surrounding soil are summarized into four categories according to the interaction mechanism during jacking: pipe-soil, pipe-air-soil, pipe-water-soil, and pipe-slurry-soil. The characteristics of the impact response wave field are simulated by numerical calculation when the impact source acts on the inner wall of the pipe under different contact relationships. The research shows that the contact relationships between pipe and surrounding soil can be determined by analyzing the energy and spectral characteristics of the waveform. When the pipe wall is in close contact with the soil, the waveform amplitude is small and the spectral distribution is narrow. When there is other medium filling, the amplitude of waveform is large, and multiple peaks appear in the spectrum. What’s more, the results of field tests show that the impact response intensity can quickly evaluate the possible distribution of the medium in the annular space and preliminarily determine the contact relationship between the pipe and the surrounding soil. Based on the numerical simulation law, the impact image method will be better applied to the practical detection.