Stabilization of sludge from earth pressure balance for use in earth embankments

The increasing use of earth pressure balance in tunnel excavations has created a challenge for constructors, namely, the handling of excavation sludge. This is an important environmental problem, and it must be solved in an efficient, economical and innovative way. This study presents a new technique for in-situ treatment of the waste by mixing it with lime. To predict the material behavior before the process, the chemical composition, morphology and texture of three samples of sludge from excavation works in a tunnel were analyzed. A quick and economical testing procedure was developed, based on the measurement of the electrical conductivity in typical mixtures. The control parameters of the in-situ treatment process were optimized to obtain enhanced soil as a final product.