Simulation of the Q2 loess slope with seepage fissure failure and seismic response via discrete element method

Deformation Development Mechanism in a Loess Slope With Seepage Fissures Subjected to Rainfall and Traffic Load

“…It is noted that due to the limitations imposed by the prevailing conditions at the study site, it is difficult to obtain undisturbed Q 2 loess samples with different water contents, such that remoulded samples with a 14-24% water content were formed in the laboratory. According to related studies (Wang Y. et al, 2019;Chang et al, 2021), the difference in mechanical parameters between the undisturbed loess and remoulded samples gradually decreases with an increasing water content and is acceptable when the water content is 14-24%. As the remoulded samples lose their structural characteristics compared with the undisturbed loess, it is necessary to convert the mechanical parameters of remoulded loess into those of undisturbed loess.…”

“…Moreover, the pore -D show the results of the seepage calculation on the slope with a 1.5-meter-deep fissure. It can be seen from the figures that the water content and pore-water pressure on the slope surface, especially at the fissure, have increased significantly after infiltration (Jin et al, 2012;Zhou et al, 2014a;Chang et al, 2021). The seepage results are used for the mechanical analysis of the slope by the method proposed in Consideration of Water Sensitivity of Loess and the steps are as described below.…”

“…Sliding surface formation stage (Figure 9D): a sliding surface is initially formed along the fissure under the continuous action of rainfall and traffic load. The fissure becomes an express channel for water infiltration under precipitation (Jin et al, 2012;Zhou et al, 2014a;Chang et al, 2021). The seepage field near the fissure is greatly affected so that the strength and stiffness of the soil are correspondingly reduced, resulting in a failure zone expanding around the fissure.…”

“…The loess has high void ratios and well-developed vertical joints (Zhang et al, 1988;Derbyshire et al, 1998), featuring a remarkably collapsibility and transverse isotropy (Jiang et al, 2014;Xu and Coop, 2016). As such distinctive soil structure facilitate water infiltration, it is very common to see seepage fissures on loess slopes (Jin et al, 2012;Krzeminska et al, 2013;Pu et al, 2020;Chang et al, 2021).…”

“…For example, Zhou et al (2014a) proposed a moving boundary algorithm for mechanical-hydraulic coupled analysis and used it to investigate the failure mechanism of a loess slope along cracks caused by infiltration of water. Chang et al (2021) simulated the failure process of fissured loess slope under rainfall and earthquake load via the PFC 3D discrete element software.…”