Backfilling for Segmental Linings in Underground Structures

Abstract

For usual backfill grouts the major advantage is the huge experience of using grout mixes whose compositions and proportions are well known and also well documented from numerous tets and observations. However, it is not possible to ensure the correct backfilling (without gaps) or the appropriate pumping conditions as the general approach followed on standards (applicable mainly on lab) cannot ensure the fitness of the product functional properties. However, for assessing and controlling such type of mixes a set of "actual" indicators must be defined and also useful protocols for testing by using non destructive techniques have to be designed for its validation. This paper deals with the testing protocol undertaken to the production of a backfill grout that fulfils the required demands defined by the contractor and owner for each case of high performance backfill.