ASSESSMENT ON LEAKAGE RISK OF SIDE IMPERVIOUS WALLS AT COASTAL LANDFILL SITES

Abstract

An evaluation method that can express the local leakage of leachate from joint sections in steel
pipe sheet pile (SPSP) cutoff walls is discussed in this study. In particular, the evaluation of environmental
feasibility (containment of leachates containing toxic substances) considering a three-dimensional arrangement
and hydraulic conductivity distribution of the joint sections in the SPSP cutoff wall is compared with an
evaluation that generally uses the equivalent hydraulic conductivity. This equivalent hydraulic conductivity
assumes that the joint section and the steel pipe are integrated; therefore, the hydraulic conductivity is
substituted with a uniform permeable layer. However, in an evaluation that employs the equivalent hydraulic
conductivity, it is difficult to consider the local leakage of leachate containing toxic substances from the joint
sections in the SPSP cutoff wall. This paper concluded that evaluations of the environmental feasibilities of
the SPSP cutoff walls with joint sections must take into account the local leakage of leachates containing toxic
substances from the joint section.