An integrated evaluation and uniformity control process for jet grouting column diameter in interlayered soils

Controlling the diameter of jet-grouted columns is difficult because of variable ground conditions and the complex interaction of grouting parameters. As jet grouting is increasingly used in space-constrained and traffic-intensive areas, traditional trial-and-error pilot tests are often impractical. This study proposes an integrated jet grouting process that couples real-time column diameter monitoring with immediate diameter uniformity control within conventional construction workflows. The proposed approach aims to improve grouting efficiency in interlayered soils and reduce geometric non-uniformity and the risk of seepage windows or weak sections occurring between columns. Field tests using a double-fluid jet grouting system were carried out to evaluate the proposed process. The results show that clay layers within the interlayered soil profile hinder column formation and cause irregular column shapes. Targeted water jet pre-cutting was applied to disintegrate clay structures, resulting in more uniform column diameters across different soil layers. By enabling a seamless transition from monitoring to corrective action based on real-time acoustic data, the proposed process allows immediate intervention when non-compliance with design requirements is detected. The proposed process improves quality and efficiency and provides practical guidance for jet grouting in interlayered ground conditions or transportation works with strict construction schedules.