Use of anionic polyacrylamide to challenge land degradation that led to slope instabilities: preliminary results

Abstract

Climate change is continuously posing new challenges to land management and conservation in built, populated and agricultural areas. Polymers such as polyacrylamide (PAM) offer a suitable tool to stem soil degradation, as well as having a wide range of applications. Informations on polyacrylamide’s use related to soil management were gathered through a literature review involving hundreds of articles. Soil samples were reconstructed in laboratory to observe the effects of PAM application on their physical, volumetric, mechanical, and hydrological properties. Two sets of samples were reconstructed using kaolin and sandy loam soil, respectively, with three different dry densities (varying between 1.2 and 1.6 g/cm3), three different initial water contents (varying between 5% and 40%) and five different polymer application rates (0%, 0.003%, 0.03%, 0.3%, and 1% by weight). The polymer, a granular anionic polyacrylamide, provided by Micronizzazione Innovativa Srl, has been manually applied and mixed with samples; then left to dry undisturbed. Preliminary results showed that the increase of PAM percentage in samples generally coincided with increase of liquid limit and plasticity index, causing at the same time a more gradual and regular release of water compared to untreated samples. These preliminary results highlight the possible application of PAM to improve other soil features which could impact on slope instabilities occurrence, in a frame of sustainable solutions for the reduction of landslides susceptibility, hazard and risk.