Experimental simulation of water and air migration under the presence of fissures and paleosols in unsaturated loess slopes

Liu, Peng; Ke, Xianmin; Wang, Wei; Liu, Yitian; Li, Xiujuan

Experimental simulation of water and air migration under the presence of fissures and paleosols in unsaturated loess slopes | Simulation expérimentale de la migration de l’eau et de l’air en présence de fissures et de paléosols dans des pentes de lœss non saturées Simulación experimental de la migración de agua y aire en presencia de fisuras y paleosuelos en laderas de loess no saturadas 裂缝及古土壤影响下非饱和黄土边坡中水气运移的试验模拟 Simulação experimental de migração de água e ar sob a presença de fissuras e paleossolos em depósitos não saturados de loess em encostas

2022

Liu, Peng | Ke, Xianmin | Wang, Wei | Liu, Yitian | Li, Xiujuan

Fissures and paleosols are important factors affecting the slope stability of loess. However, the mechanism of water and air migration in the unsaturated zone of loess induced by fissures and paleosols remains unclear. In this study, discontinuous irrigation experiments were conducted using a sand tank and Marriott bottle. The soil- water content (SWC) patterns and pressure differences, under the influence of fissures and paleosols, were observed using the EC-5 moisture sensor and MPXV5010DP differential pressure sensor. The results showed that the fissures are the dominant channels of water infiltration and air exchange, while paleosols and closed soil boundary conditions can significantly impede the downward transport of water and air. During irrigation, SWC near the fissure and paleosol increased rapidly from less than 10–30%, reaching a maximum value of 35% above the paleosol. On the other hand, the maximum pressure difference in the upper part of the paleosol exceeded 1,000 Pa, which is significantly higher than that observed in the lower part. The stability of soil around fissures and paleosols decreased sharply due to high SWC and pressure differences, which may induce landslides after long-term irrigation. This study provides a theoretical basis for revealing the formation mechanism of landslides in loess irrigation areas and preventing landslide disasters.

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