Physical clogging experiment of sand gravel infiltration with Yellow River water in the Yufuhe River channel of Jinan, China

To make sense of physical clogging during Yellow River water spreading in the strong leakage zone of the Yufuhe River, a laboratory sand column experiment was undertaken and the heterogeneous sand gravel with a uniformity coefficient of 25.2 from the Yufuhe River was used as an infiltration medium. Under either the condition of raw sand or washed sand, physical clogging tests were conducted with constant hydraulic heads of 10 cm and 30 cm and inflow suspension concentrations of 200 mg/L, 500 mg/L, and 1000 mg/L. The fine particles in the suspension and in the raw sand were considered exogenous and endogenous particles, respectively. Rapid clogging was observed in the porous medium when the inflow concentrations of the exogenous particles were high, and increased hydraulic head led to serious clogging. This result indicated that the Yufuhe River has a strong recharge capability with respect to clogging. The analysis of particle content shows that endogenous fine particles (diameter 1–10 µm and 50–74 µm) had less mobility and generally accumulated in the sand column, whereas particles with diameter 10–50 mm had greater mobility in the sand column. And the distribution of exogenous fine particles size after movement is relatively uniform in the sand column. Field observations indicated that the filtration effect of the aquifers have greatly improved the water quality of recharge water in the strong leakage zone of the Yufuhe River, and test data of turbidity also verified the results of the sand column experiments.