Physical-based subgrade compaction assessment combining vibratory response and real-time soil deformation

As a non-destructive method for monitoring subgrade compaction quality, intelligent compaction (IC) suffers from limited accuracy due to the dependency of interference-prone vibration feedback signals. Comparing to the indirect IC evaluation indexes, the soil compressive deformation directly reflects compaction quality. This study proposes a continuous monitoring system to record the soil deformation in real-time, serving as a physical index to the compaction quality assessment. Field tests are conducted by integrating the IC and this monitoring system. The physically interpretable compactness evaluation model is established by combining the multi-variate IC data and the real-time soil compressive deformation. The model’s generalization is significantly enhanced. A three-dimensional numerical model is further developed to quantitatively analyze the entire compaction process. The mechanism of vibration energy transmission and evolution of soil skeleton are demonstrated using force chain networks and particle velocity fields. The research achieves direct quantitative evaluation of compaction quality through soil deformation while elucidating the intrinsic mechanisms of compaction formation, maintaining assessment accuracy and providing theoretical foundations for engineering applications of intelligent compaction technology.