Failure behavior of soil slopes stabilized by urease enzyme at different angles

Reza Yousefi¹ Amir Abbas Amooei² Mohammad Sajjad Soltani³

1) Masters student of geotechnical engineering, Qom University of Technology -
2) Masters student of geotechnical engineering, Qom University of Technology -
3) Masters student of geotechnical engineering, Qom University of Technology -

IOI Code : XCZC-ECCKK
Publication : International Conference on Emerging Trends in Engineering, Science and Technology(etest2020.com)
Abstract :
    In evaluating the stability of soil slopes, its stability analysis plays a decisive role. Generally, to prevent slope instability or the design of a stable slope, there are three ways to move the layout of the plot, reduce the thrust forces, and enhance the slip forces to avoid the risk of slipping. Since the criterion of slope instability is the equilibrium of thrust force and resistance, weight loss of the slippery slope will decrease the thrust forces and thus increase the factor of safety in displacement. Nowadays biologically and environmentally friendly methods are used as a subset of environmental geotechnics for soil stabilization. One of these methods is using urease enzyme for hydrolyzing urea and formation of calcium carbonate precipitation in soil pores, which results in increment of soil strength and cohesion. Therefore, many studies have been carried out to identify the behavior of soils improved with this method, but limited modeling has been done on the real issues of stabilization. In this study, the effect of calcite precipitation in sandy soil was investigated by using direct shear test and modeling the results by limit equilibrium analysis method in two states, one in presence of groundwater and the other without considering it. In the limit equilibrium method, the probability of rock or soil mass slip due to gravity is investigated. The results show that in this method, soil stabilization has increased the stability factor of safety. The effect of slope angle on the stability of the slope stabilized by urease enzyme was also investigated. The modeling results showed that with increasing soil slope angle, slope stability decreased.Also the stability factor of safety in unsaturated state was higher than saturated state.

Keywords : soil slope factor of safety limit equilibrium method (lem) slope angle sand urease enzyme