Some considerations on the restorative effectiveness and efficiency of the groundwater pumping in impervious wall

摘要

In order to find a simple way to estimate the restorative effect of pumping ground water in a section of ground sealed with an impervious wall of steel sheet piles and so on, unsaturated seepage column tests using a solution of TCE solvent or salt water were carried out and various observations made. The results showed that the restorative effect of pumping ground water is dependent on the degree of saturation of the contaminated ground and may be evaluated quantitatively from the water retention curve of the ground. Further, as a measure to improve the restorative effectiveness in clayey ground, the formation of 'water courses' using a sand pile method of ground improvement (sand drain method) was considered, and improvement in restorative effectiveness was estimated from a saturated-unsaturated seepage analysis. The results showed that the restorative efficiency was improved by the groundwater pumping method with sand piles.