Multiscale Assessment of Biopolymer Soil Amendment for Earthen Embankments

An initiative to investigate environmentally friendly soil additives to improve the material properties of soils has been undertaken by the U.S. Army Corps of Engineers (USACE), Engineer Research and Development Center (ERDC), Geotechnical and Structures Laboratory. USACE operates and maintains over 740 dams, and there are over 7,000 total levee systems in the United States with over 2 trillion dollars’ worth of property protected. Traditionally, when slope instability occurs, the soil is treated with lime or cement to improve the engineering characteristics of embankment soils and prevent future instabilities. The production of traditional soil additives contributes adversely to the global climate. For example, the production of cement releases carbon dioxide by up to 0.55 tons per 1 ton of Portland cement (Chang et al. 2016). Therefore, more environmentally friendly alternatives are being explored for improving the engineering characteristics of embankment soils.

There have been multiple investigations in the literature exploring the improvement of soil properties using biopolymers. There have been few large-scale studies in hydraulic flumes and limited field applications. The objective of this study was to perform extensive laboratory investigations on the impact of applying biopolymer to soils with testing of shear strength and erosion resistance. In addition, multiple field studies were conducted to explore the performance of biopolymer treated soils in a field setting and the scalability of applying biopolymers in a full-scale setting. The objectives of this paper are to present the results of both approaches in the context of two time scales: a short-term, post-application period and a long-term period.