Research on the optimization of grouting flow detection sensor layouts based on laser ranging technology

Accurate grouting flow measurement is critical for optimizing construction quality and reducing material waste in geotechnical engineering. While electromagnetic flowmeters are widely used, their precision deteriorates significantly under low-flow conditions. This study proposes a laser ranging-based method to address this limitation by analyzing slurry liquid level fluctuations in mixing drums. Through theoretical modeling, indoor experiments, and numerical simulations, the liquid level fluctuation patterns under varying water-cement ratios (0.5:1–5:1) and stirring speeds (40–80 r/min) were investigated. Key findings reveal that liquid level stability increases radially outward from the stirring shaft for ratios ≥0.7:1 but inversely for 0.5:1. The slurry surface was categorized into three zones: a turbulent central zone (within 1/3 radius, R/3), a stable intermediate zone (R/3–7R/8), and a high-fluctuation wall zone (7R/8–R). Optimal sensor placement in the stable zone reduced measurement errors to 0.83% (power-function-distributed sensors) and 1.12% (uniformly spaced sensors), significantly outperforming electromagnetic flowmeters (up to 20% error). This work provides a validated framework for sensor layout optimization, enhancing the reliability of laser-based grouting flow detection in practical applications.