Evaluating permeability and groutability of Souk Tleta dam site based on Lugeon tests, RQD, SPI and trial grouting

Abstract

This study is conducted mainly to evaluate the permeability and the groutability at Souk Tleta dam site. It is an embankment dam with a height of 95 m and a crest length of 200m located in the Tizi-Ouzou province in Northern Algeria. The foundation of the dam consists of thick deposits of pervious alluvium of about 21 m and Burdigalian sandstone formations. The main problem of this dam is that the bedding plains of Burdigalian sandstone in the dam site are parallel to the flow direction. To conduct this study, permeability of formations is evaluated by Lugeon test and secondary permeability index. Rock quality is evaluated by geological assessment and RQD values. Results indicate that the overall permeability of the foundation rock mass before trial grouting in more than 54% of the Lugeon tests is high and requires treatment. To investigate effect of grouting in reducing permeability of rock mass and to evaluate the grout take in rock masses, two trial grouting programs are carried out on dam foundation and left abutment of dam site up to maximum depths of 70 m and 67 m, respectively.

Keywords

• groutability
• souk tleta dam
• permeability
• trial grouting