The shield tunneling method is a construction technique that uses shield machinery to excavate tunnels underground. It has now become a major means of constructing tunnels in soft soil and soft rock. Grouting behind the tunnel wall is a key technology for controlling the quality of tunnel construction. However, since grouting behind the wall is an invisible project, there are currently no effective detection methods to accurately measure the thickness and distribution of the grout body. This uncertainty leads to uncertain factors affecting both the construction and maintenance of shield tunnels. The main purpose of this invention is to adapt to the rapid development of shield tunnel excavation construction and meet the requirements of tunnel construction detection technology towards precision, speed, and non-destructive testing.