Model tests and numerical analysis of emergency treatment of cohesionless soil landslide with quick-setting polyurethane

Shotcrete is one of the common solutions for shallow sliding. It works by forming a protective layer with high strength and cementing the loose soil particles on the slope surface to prevent shallow sliding. However, the solidification time of conventional cement paste is long when shotcrete is used to treat cohesionless soil landslide. The idea of reinforcing slope with polyurethane solidified soil(i.e., mixture of polyurethane and sand) was proposed. Model tests and finite element analysis were carried out to study the effectiveness of the proposed new method on the emergency treatment of cohesionless soil landslide. Surcharge loading on the crest of the slope was applied step by step until landslide was triggered so as to test and compare the stability and bearing capacity of slope models with different conditions. The simulated slope displacements were relatively close to the measured results, and the simulated slope deformation characteristics were in good agreement with the observed phenomena, which verifies the accuracy of the numerical method. Under the condition of surcharge loading on the crest of the slope, the unreinforced slope slid when the surcharge loading exceeded 30 k Pa, which presented a failure mode of local instability and collapse at the shallow layer of slope top. The reinforced slope remained stable even when the surcharge loading reached 48 k Pa. The displacement of the reinforced slope was reduced by more than 95%. Overall, this study verifies the effectiveness of polyurethane in the emergency treatment of cohesionless soil landslide and should have broad application prospects in the field of geological disasters concerning the safety of people's live.