Compaction Quality Control and Assurance of Silt Subgrade Using Roller-Integrated Compaction Monitoring Technology

The compaction quality is critical to the stability and durability of highway subgrades. Currently, there is a clear lack of research on the specific application effects of roller-integrated compaction monitoring (RICM) technology and RICM measurement values for silty soil, which are difficult to compact and have unique material properties. In addition, practical applications have shown that existing assessment methods based on geostatistical methods have many shortcomings that need to be addressed urgently. In this study, RICM technology was combined with a real-time kinematic Beidou positioning system to monitor the compaction of subgrades filled with two types of silt. First, field experiments were conducted, and the correlations between the RICM measurements, compaction parameters, and in situ measurements were analyzed. The compaction control value (CCV) was then selected by comparing with E to achieve a more reliable monitoring and assessment. Subsequently, different types of quality regression models were established to find a model that considers the advantages of accuracy and convenience, which was then used to estimate the compaction quality. Subsequently, a CCV- and Green spline interpolation-based method was proposed to calculate both the CCV and compaction quality and draw color-coded maps at any location. A case study demonstrated that CCV are highly correlated with the compaction parameters and the compactness and can serve as a reliable index for monitoring compaction quality owing to its strong stability and low dispersion. Taking moisture content into account can make the regression model more statistically significant and improve the correlation. The proposed assessment method effectively solves the problems of the existing method. A rapid and continuous assessment covering 100 % of the work area can be achieved using the proposed method to provide timely identification of quality defect areas and feedback improvement, thus realizing effective quality control and quality assurance of highway subgrades.