An innovative solution to the stabilisation of the Caimmuir Landslide incorporating reinforced earth

Caimmuir Landslide is an active schist rock slide, with a volume of 8 million m3, located above Lake Dunstan, the Clyde Dam reservoir in the South Island of New Zealand. Slide velocities of up to 180 mm/year have been measured. Despite underground and surface drainage measures, the slide kept moving, particularly when wet, necessitating surface infiltration protection over an area of 3.8 ha in the toe region of the slide. A unique combination of Reinforced Earth terraces with bitumen sealed runoff surfaces was implemented. The Reinforced Earth technology provided ease of construction, flexibility to follow ground contours, deformation tolerance and natural appearance. Post-construction performance has confirmed the effectiveness of the solution.