Effects of Trichoderma Fungus on Clayey Soil Properties

Traditional soil stabilization methods often involve chemical or mechanical techniques, which may have adverse environmental impacts. With technological advancements, these conventional methods such as static or dynamic compaction, cement injection, micropiles, and nailing are gradually being replaced by environmentally friendly techniques. For instance, soil improvement through methods like Microbially Induced Calcite Precipitation (MICP), Enzyme Induced Calcite Precipitation (EICP) and Fungal treatment offers sustainable alternatives, minimizing chemical and noise pollution while reducing costs. Although significant research has been conducted on MICP, many gaps still exist, especially regarding its application to various soil types. In contrast, limited engineering research has focused on implementing fungus.

This study investigates the effects of fungal treatments, specifically by means of Trichoderma asperellum, on the physical and mechanical properties of clay soil coming from the northern Italian Apennines. The tested soil is characterized by a clay content up to 56% and the clay minerals are represented by smectite; this soil is affected by swelling-shrinkage and shallow landslide. This research examines the erodibility of the soil aggregate during wet sieving, water retention curve, consolidation features, shear strength parameter, and Atterberg limits under laboratory conditions using the fungal suspension mixing application methods. Testing was conducted using Casagrande spoon, Oedometer, Direct Shear test, a coupled system of an evaporation technique apparatus and a dew-point technique, and wet sieve apparatus.

Additionally, comparisons were made between treated and untreated (control) soils, with pore water pressure analyzed using the Van Genuchten model and Mualem’s conductivity model in RETC software.

These findings underscore the potential of fungal treatments as viable methods for enhancing soil performance, offering an eco-friendly alternative to traditional soil stabilization techniques. Further studies are recommended to analyze long-term impacts and scalability for field applications. This research contributes to the development of biologically based soil improvement methods, aligning with sustainable land management practices.