1. Slope Stability Analysis Under Critical Conditions of Geogrid Reinforced Canal Embankment

Nowadays, biaxial geogrid is extensively used as a reinforcing inclusion to enhance the shearing resistance of pavement sub-grade, backfill materials of earth retaining structures, and also arresting the slope failure of the earth embankments. In the present study, the performance of the geogrid reinforced canal embankment has been assessed through numerical modelling using a finite element-based PLAXIS 3D software package. Slope stability of canal embankment depends on the geometry of side slopes, in situ soil condition, and the effects of excess pore water pressure. The soil samples have been collected from the canal bed and embankments of an existing canal at Durgapur City, West Bengal, India, to investigate the vulnerability condition of canal failure. The canal runs from Durgapur barrage to Durgapur steel thermal power station to fulfil the daily needs of water to the industry. However, the canal-side slopes are presently in a damaged condition. Preliminary stability analysis of the canal slopes indicates low safety margin which may instigate failure under critical conditions. The present study has been conducted in order to improve the slope stability of the aforementioned canal structure with the inclusion of geogrid layers. The geogrid reinforced slope stability analysis of canal embankment has been carried out under different critical conditions viz. high reservoir, low reservoir, rapid drawdown, and slow drawdown. The critical values of slope angle and embankment height were found to be 45° and 6 m, respectively. The factor of safety of the embankment increased considerably in critical conditions with the inclusion of geogrid on side slopes and under canal bed.