Richardson Road Landslide – Remediation of a Complex Landslide for Pipeline Security

PDP completed a project addressing a landslide that affected a critical gas transmission pipeline in South Auckland. This work was essential for maintaining the integrity of the pipeline and preventing further affects. Our team was responsible for determining the landslide model and developing stabilisation and ongoing monitoring strategies for the complex, large scale landslide that was activated by a heavy rainfall event. We conducted geotechnical investigations, assessed groundwater influences and provided remedial works optioneering and detailed design. PDP staff also carried out construction supervision. The remedial works involved a number of key components:

• Ecological assessment of watercourses for consenting.
• Safely removing landslide debris and constructing a toe buttress to prevent additional instability.
• Installing a deep sub-surface drainage system to control groundwater.
• Excavating and realigning the pipeline to relieve stress.
• Installing a monitoring system including groundwater measurements, inclinometers and ground survey network.