BOREAL, Bio-reinforcement of embankments by biocalcification

Abstract

Biocalcification is a recent in-situ soil consolidation solution. It is obtained by calcite precipitation under controlled biogeochemical conditions. The industrial process, for whose implementation Soletanche Bachy holds several patents, has been validated by several experiments, initially on laboratory scale and later in situ on industrial scale under static groundwater conditions. However, it was necessary to adjust the process to make it effective for use in embankments due to the potentially high ground water flows that may be present. This is one of the main aspects addressed by the BOREAL project (Bio-reinforcement of backfilled hydraulic structures), a 4-year research and development program. Injection tests performed on a 1:1 scale in a physical model allowed for the validation of the process' feasibility in various soil types and configurations as well as under several hydraulic flow conditions. The prime objective of the process is to help mitigate erosion and liquefaction risks. The project's results are applicable to saturated and non-saturated soils. The areas of application of the process and its objectives in terms of treatment are also discussed in the article.