Investigation on the Permeability Coefficient of Sand Soil Impacted by the Seepage Erosion via Laboratory Test

Seepage erosion inside sand soil occurs when the hydraulic gradient exists, and geology disasters are likely to happen when the seepage erosion develops to a certain degree. The seepage erosion leads the migration of soil particle, which can reflect for the change of the permeability coefficient of the soil. A laboratory test on horizontal seepage erosion in sand soil is conducted to discuss the influence of seepage erosion on the permeability coefficient. The hydraulic head difference (Δh) ranges from 300 to 900 mm in the laboratory test, and seven monitoring points for the groundwater level along the seepage path are set on the horizontal tubular experimental apparatus. The result indicates that the approximately average permeability coefficient of the whole experimental sand soil (kav) presented rising tendency generally with the increase of Δh, and the variation tendency of the permeability coefficient of the soil between two monitoring points (kij) was different along the seepage path. When Δh increased from 0.3 to 0.9 m, kij near the start part and the end part increased while fluctuated around the middle. The kij close to the start and the end of the seepage path was more easily to be affected by seepage erosion than that around the middle.