Prediction Method for Ca Leaching and Related Property Change of Cement Treated Soil

Abstract

Deep mixing method has been applied to improve soft ground for over 25 years in Japan. However, the possibility of deterioration of treated soils has not been studied in detail. In this paper, long-term strength change of treated soil was investigated. The paper consists of three parts. In the first part, the strength characteristic of in-situ treated soil after 17 years is investigated. In the second part, Ca (calcium) leaching phenomenon from treated soil to surrounding soil is investigated in situ. And in the third part, the numerical prediction method for Ca leaching from treated soil is proposed. It is confirmed that after 17 years the treated soil has sufficient strength characteristics, although it is slightly influenced by Ca leaching. The related property change to Ca leaching from treated soil can be expressed using numerical analysis considering ion migration model and Ca leaching model.