Abstract:

The experimental study focuses on the development of plastic zone in the coarse‑grained soil slope under the limit condition, and the plane strain test with different particle sizes is carried out. The changes of stress and strain in the soil are monitored. The width of the plastic band was measured, and the parameters of the plastic band were studied. The results show that the formation of the plastic band is a gradual process, which takes the occurrence of the strain bifurcation point as the trigger sign and starts before the peak of the stress‑strain curve and forms after the peak. The larger the particle size is, the longer the time required for the trigger is, and the band width increases to varying degrees. At the same time, compared with the traditional limit analysis, the plastic belt has a certain effect on the ultimate load of the slope. And the critical slip surface is located on the plastic belt, which proves the rationality of the position of the slip surface. It shows that there is an important correlation between the stability of the slope and the plastic belt.

Key words: plane strain, coarse?grained soil, plastic band, model test