Drainage mats: study of compressive creep

Abstract

The drainage mats are systems consisting of a drainage core and at least one filter layer. ln engineering, they are used for directing water along its own plane. However, compressive creep, due to soil pressure, can seriously limit the effectivencss of the drainage materials. To measure the way in which the thickness of geosynthetic materiais reduces in time under load, the European Committee for Standardization (CEN) developed the draft standard prENV 1897: Geotextiles and geotextile related products - determination of thc compressive creep properties.  This test method does not simulate many of the in situ boundary conditions of the drainage mats, in view of the fact that it establishes only the contamment of test specimens w1th hard surfaces. This paper presents the experimental work undertaken by the Laboratório Nacional de Engenharia Civil to study the feasibility of carrying out compressive creep tests based on the aforementioned draft standard, but bounding the test specimens with compressible surfaces.