Torcy-Vieux dam (71 France) sampling, tests and results on geotextile filters

Abstract

The Torcy-Vieux dam is a homogeneous earthfill dam, which was built around 1800. There were several phases of construction interrupted by incidents and repairs. In 1987, the last one consisted in logging trees on the downstream slope, boring 12 drainage wells on the downstream toe and building a downstream shoulder of about 4 m height, with drain wrapped around with geotextile filters. In 1997 an inspection operation noticed seepages on the superior part of the downstream slope. A more acute analysis came to the conclusion of a high risk of internal erosion and clogging of the drain geotextile filters. In august 1998, the pulling down operation of the downstream shoulder gave opportunity to take samples and do laboratory tests. Their results are given in this study report.