In Situ Frost-Heaving Characteristics of Shallow Layer of Soil Slopes in Intermittently Frozen Region Based on PFC3D

The in situ frost-heaving (FH) process and characteristics of the shallow layer of a residual soil slope in the intermittently frozen zone were simulated by a modified three-dimensional particle flow code (PFC3D) model, of which the mesoscopic parameters of soil and ice particles were calibrated through the indoor experiments. In this model, the in situ FH process was gradually achieved by expanding the volume of ice particles (divided into 24 times of expansion), and the process was terminated when the monitored porosity was stable. These countermeasures avoided the stress accumulation and effectively realized the simulation of the in situ FH process. The results found that the displacement occurred firstly and got the largest final value at the surface angle (SA) under the in situ FH effect, followed by that at the foot, and it gradually extended to the interior based on these two regions. The vertical tension was present at the SA, and the major force type in the lateral interlayer was pressure. In addition, the FH effect seemed to be strongly related to the frozen depth, and a sliding surface was found in a steeper slope. Finally, the smaller stone appeared to be favorable to the slope stability, but it was reduced by the larger stone to some extent.

APPLICATION OF PFC 3D FOR SLOPE MOVEMENT ON COLLUVIAL SOIL

In the mountainous area of the tropics, soil creep often occurs on residual soil and colluvial deposit. The rate of this phenomenon varies from very slow to extremely slow and is difficult to detect without equipment as well as model. Within PFC3D (Particle Flow Code in three dimensions) granular materials such as soils are simulated by balls. And the PFC3D model was applied for colluvial soil creep. Although existing of some limitations, this application determined direction of creeping as well as zone of creeping of culluvial soil.