Investigating Soil Compaction and Its Impact on Physical and Hydraulic Properties Using a Simple Testing Apparatus

Various laboratory methods are used for packing sieved soil, thus influencing soil properties. This study tested a simple packing method and determined compaction effects on the dry bulk density, ρb, and saturated hydraulic conductivity, Ks, of three sieved loamy soils (AR, LE, OR). For the compaction energies, Ep, of 1 to 100 kJ/m2, the LE soil, with a similar content of large (>0.25 mm; 53%) and small (<0.25 mm; 47%) undispersed soil particles, yielded higher ρb (1.43 g/cm3) and lower Ks (23 mm/h) values as compared with the AR and OR soils (ρb = 1.12−1.14 g/cm3; Ks = 166−167 mm/h), which had a larger percentage of undispersed coarse particles (65−68%). Higher Ep values induced a decrease in Ks by 10.0, 2.5 and 16.4 times for the AR, LE and OR soils, respectively. Significant Ks vs. ρb relationships (coefficient of determination, R2 ≥ 0.62) were observed for each soil. A loamy soil with a small Ks value in little compacted conditions can be less affected by Ep than a similar soil with a high Ks value. The packing method should be reported in investigations into the physical and hydraulic properties of sieved and repacked soil.