Agarose gel as a soil analogue for development of advanced bio-mediated soil improvement methods

Abstract

Bio-mediated soil improvement methods (those that use biological processes) have potentially low cost and environmental impact, but can be difficult to control to ensure effective results, especially if engineered bacteria are used. A novel application of using agarose gel as a soil analogue is proposed, which can enable development of advanced bio-mediated soil improvement methods by reproducing relevant mechanical properties while allowing complex biological processes to be studied in detail, before testing in soils. It is envisaged that agarose gel will be used instead of soil when developing early-stage prototype methods, as it provides an ideal environment to facilitate growth and monitoring of bacteria. A programme of geotechnical tests and scanning electron microscopy on Agarose Low Melt (LM) gel is presented. The results demonstrate comparable pore size, undrained strength, and permeability to soft clays and peats, but more linear stress–strain behaviour and higher compressibility. This paper offers proof of this novel concept, but further investigation is required as only a single type of agarose, at a single concentration is tested. By varying these factors, along with use of different solvents, there is significant potential to tune the behaviour of the analogue to particular soils or construction scenarios.