Evaluating the feasibility of using guanidinium salts as a means of in-situ soil strengthening

ABSTRACT: There are a variety of engineering problems for which conventional geotechnical solutions are either impractical or ineffective; thus, the need for a multi-disciplinary approach has become apparent. When it comes to slope stability, challenging sites are found worldwide in clayey soils and weak rocks. In Saskatchewan and eastern Alberta, particular problems are associated with shallow soil deposits in highly plastic smectitic clays, clayey tills, and in weak shales with lenses of highly plastic smectitic clay. Given the extremely low residual shear strengths of these materials, shallow creeping failures are common and threaten infrastructure such as roads, bridges, and pipelines. The current research is intended to evaluate the feasibility of modifying the porewater chemistry of such soil deposits using guanidinium chloride (C(NH2)3Cl) to effect mineralogical alteration through ion exchange, as a means of insitu soil strengthening. The effect of guanidinium on geotechnical properties (relevant to slope stability) for various local soils has been evaluated through batch tests and lab-scale treatment trials. Using four local prairie soils, the effect that guanidinium salts have on soil behaviour was evaluated through testing of index properties, x-ray diffraction, and residual shear strength.