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.

Effects of Biological Stabilization on the Water Retention Properties of Unsaturated Soils

“…MICP has also shown considerable success in field trials aimed at ground reinforcement (van Paassen et al 2009(van Paassen et al , 2010DeJong et al 2014;Gomez et al 2015;Esnault-Filet et al 2016;Terzis and Laloui 2017). However, applications of MICP face a great challenge in terms of the nonheterogeneous distribution or penetration of treatment across and into soil volumes.…”

La biocalcification bactérienne en milieu marin et ses applications

“…Les bactéries et les réactifs sont mélangés au matériau granulaire, pulvérisés sur une surface ou injectés ensemble à grande vitesse ou sous pression [23]. Un procédé innovant de renforcement des sols in situ, par biocimentation, est ainsi proposé par la société Soletanche Bachy au travers de son brevet Biocalcis ® [26,136]. Ce traitement consiste à injecter une suspension bactérienne et une solution de cimentation sans pression.…”