To address the large treatment area and tight construction period of large-scale engineering site filling foundations and to ensure the quality and progress of the project, understanding the foundation-reinforcement treatment quickly and accurately is essential. Additionally, to ensure the safety and stability of projects, large-scale projects often have higher requirements for the uniformity of the foundation-soil reinforcement effect. The quality-evaluation indices of foundation-soil compaction and reinforcement mainly include the foundation-bearing capacity, foundation-soil deformation modulus, and compaction coefficient. Conventional testing methods primarily include in-situ loading tests, in-situ sand filling, and soil-sample testing. These methods are either labor-intensive and time-consuming or harmful to the reinforced foundation-soil mass, preventing rapid and continuous detection of the foundation-soil mass. To perform rapid and continuous detection of the compaction and reinforcement effects of foundation-soil mass, the multichannel transient Rayleigh wave-detection method, considering the time difference phase between channels, was used in this study. Additionally, the method was supplemented by the sampling tests of soil mass at selected points in this study. Consequently, continuous three-dimensional imaging of the elastic wave velocity of the foundation-soil mass was obtained, along with the horizontal slice of the Rayleigh wave phase velocity imaging and the horizontal-distribution imaging of the depth-average compaction coefficient of the foundation-soil mass. The results reveal that the foundation-soil mass imaging can accurately reflect the compaction and reinforcement effects of the foundation-soil mass, thereby providing a reliable basis for evaluating the quality of foundation-soil mass reinforcement.