Experimental Study on Reinforcement of Subgrade Slope with Loess-based Grout and Composite Soil Nails

Abstract

In order to investigate the impact of controllable low-strength yellow soil slurry as grouting material and slope protection layer on the stability and bearing capacity of roadbed slopes. The study used yellow soil as the main experimental material, combined with additives such as cement, sodium sulfate, and ethylene glycol, successfully developing a controllable low-strength fluid material, namely, yellow soil slurry. Based on this, with steel bars as reinforcing material and yellow soil slurry as grouting material and slope protection layer, indoor scaled model tests were conducted relying on the similarity principle, using the yellow soil from a roadbed slope project in Lanzhou. Using slope top settlement and foot bulge as mechanical response indicators, the study investigated the effects of slope gradient, soil nail length, angle, and spacing on the stability and bearing capacity of roadbed slopes. Experimental results indicate that indoor model tests found that the gentler the slope, the higher the stability, and soil nail length and density can enhance the bearing capacity of the roadbed; the reinforcement effect on the roadbed slope is most significant when the angle between the soil nail and the horizontal direction is around 10°. The study results are of reference significance for the application of yellow soil slurry in roadbed slope engineering.