Towards sustainable soil management: Reuse of excavated soils with natural contamination

Abstract

Status of regulations, practices, and challenges on the reuse of excavated soils with natural contaminations in Japan are presented. Geotechnical and geoenvironmental efforts have been conducted in recent years to contribute to the cost-effective measures to reuse such excavated soils under proper contaminant control. Evaluations of leaching behavior from the soils of concern as well as attenuation capacity of the surrounding ground are both essential to design the cost-effective measures. Since methods and/or protocols which consider the nature of natural contamination are required, several different leaching tests were performed on different types of soils and rocks with natural contaminations by the authors. A series of these experimental works revealed that the testing conditions of column leaching tests, such as column length and flow rate, should carefully be decided to simulate the situations where the soils are reused in embankments or other geotechnical applications. Either original grounds or soil layers installed beneath the naturally contaminated soils are expected to function as attenuation layer. Therefore, attenuation capacities of several different types of soils are discussed. Effects of mineral agents enhancing the sorption performance are also presented in this paper.