Clogging and flow characteristics of a geosynthetic drain confined in soils undergoing consolidation

摘要

ABSTRACT: This paper describes clogging and in-plane flow characteristics of a permeablengeosynthetic layer confined within fine-grained soils that undergo time-dependent settlement. Thendrain layer was placed within a slurry, and measurement of water from the drain layer was recorded.nIn-plane flow capacity of the drain layer was checked at the end of consolidation. The permeabilitynof the geosynthetic drain layer was found to be at least 105ntimes the corresponding permeability ofnthe soil. In order to prevent clogging, a hybrid drain system consisting of a thin sand mat between thensoil and geosynthetic layer was investigated. This system showed excellent drainage performance duento good filtering capability of the thin sand mat. New terms, such as ‘permeability factor’, ‘drainnperformance factor’, ‘confining pressure factor’ and ‘clogging potential’ of drain, are defined andnevaluated from the experimental data. Clogging potential of the hybrid drain layer was found to benlow (< 2), and was observed to reduce with an increase in consolidation pressure. Without the thinnsand mat the clogging potential showed an increasing trend with increasing consolidation pressure.nFinally, this paper recommends potential application of the hybrid drain system to improve stabilitynof soil structures constructed with poorly draining backfills such as Kanto loam in Japan.