Investigation into the Effect of Enzymes on the Erodibility of a Low-Plasticity Silt and a Silty Sand by EFA Testing

摘要

Enzymes provide a nontoxic alternative to toxic products used in soil improvement and are economically attractive. For example, enzymes have been used in road construction to improve the durability of the base and the subbase of pavements. Would enzyme-treated soils exhibit higher resistance to erosion than untreated soils? That is the question. Erosion function apparatus (EFA) tests were conducted to provide an answer. The EFA is a laboratory device used to measure the erosion function of a soil defined as the relationship between the soil erosion rate and the water velocity or the water shear stress. In this study, three different types of enzymes were used to treat two different types of soils: a low-plasticity silt and a silty sand. For each sample, the selected water content was the optimum value from the Proctor compaction test. For each enzyme, two different concentrations and two different treatment periods were considered. The measured erodibility of the enzyme treated soils was compared with the measured erodibility of the untreated soils. The results showed that enzyme-treated soil samples exhibit higher resistance to erosion than untreated samples.