Measures of risk mitigation for landslides induced by irrigation

Groundwater rise due to perennial irrigation contributes to the occurrence of landslides, and this is the basic feature of landslides induced by irrigation. The employment of groundwater level control is a fundamental measure for landslide risk mitigation. Drainage measures comprising irrigation volume control, vertical drainage by multi-aquifer wells and horizontal drainage were presented. Changes of groundwater flow field under different irrigation volumes and the corresponding slope stability were simulated, and drainage effects with different arrangements of multi-aquifer wells were also calculated. According to the results obtained, a reasonable irrigation volume of 350×104m3/a is defined to achieve risk mitigation, and an interval of 40m between wells is determined as a reasonable distance to increase the slope stability. Considering various factors, the authors proposed a comprehensive risk mitigation method, which takes irrigation volume control as the main means and vertical and horizontal drainage measures as auxiliary methods.