Use of Anionic Polyacrylamide to improve soil properties and challenge slope instabilities: preliminary data

Nowadays, changing climate is continuously posing new challenges to land management and conservation, also in built areas and agricultural fields. Polymers such as polyacrylamide (PAM) offer a suitable tool to stem soil degradation, as well as having a wide range of applications. We performed a detailed investigation about this polymer applications with particular attention to the field of slope instabilities through a systematic literature review to assess the extent and the specifics of the research done on Polyacrylamide as an improver of soil features, browsing between more than 800 articles published from 1990 to 2022. Research on polyacrylamide application increased since the 2000s, its main use being the prevention of irrigation-connected erosion, even if in more recent years its ability as a soil stabilizer became more and more newsworthy. We then proceeded to reconstruct soil samples in laboratory to observe the effects of application of anionic polyacrylamide (PAM) on their physical, volumetric, mechanical, and hydrological properties. First, 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 10% 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 the samples, constituted by pvc cylinders with a diameter of 9.5 cm and 15 cm high. 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 samples water compared to untreated samples. These preliminary results can stress on the possible application of PAM to improve other soil features which could impact on slope instabilities occurrence, in a frame of sustainable solutions for reduction of landslides susceptibility, hazard and risk.  Keywords PolyacrylamideLandslidesSoil conservationLand degradation