Time-lapsed in situ monitoring of mechanical property in deep soil mixing with surface wave

Evaluating the mechanical properties of deep soil mixing (DSM) requires destructive borehole coring because they are mainly situated underground. Although the surface wave method offers potential for quality assurance, its complexity arises from multi-mode phenomena and the need to re-evaluate inversion results, often necessitating manual interpretation. This paper presents a data-driven surface wave framework to retrieve a field DSM profile V_s over time, incorporating a mode-free forward operator and the Monte Carlo tree search inversion. Validations using synthetic data affirmed the framework’s accuracy and efficiency in tracking subsurface shear wave velocity. In a real-world DSM site, the proposed method successfully captures the evolution of mechanical properties across two DSM layers over the curing period, aligning well with site investigations and borehole coring. This pioneering monitoring framework integrates geotechnical engineering with geophysics expertise, underscoring the value of non-destructive seismic methods for measuring subsurface property evolution.