Drilled subsurface drainage is used to drain groundwater to stabilize the landslide by decreasing the pore water pressure to affect to increase the resistance force at the sliding surface. The work is useful as a temporary countermeasure to decrease the progress of an active landslide, as well as permanent measuer.
If this surface runoff is not drained by slope surface drainage, water may overflow to the downhill areas and cause serious slope disasters. Slope drainage facilities should be designed to prevent both surface erosion and the collapse of slopes.
Objectives: The objectives of vegetation are to:
Purpose is to prevent erosion of the rock slope along with the weathering of the slope and a decline in the strength of the ground that forms the slope by protecting it from rainfall, wind, hail stone, and tree roof.