Over the past 15 years this steep slope located at km 108, adjacent to the secondary pipeline and right-of-way, had experienced several failures. In June 2019, a military patrol reported another landslide of signiﬁ cant proportion within the previously remediated stabilisation work. A slope stability analysis was undertaken by the client, Pluspetrol, to identify further potential instability within the slope and determine a suitable remedial solution.
Due to the remote location of the slope it presented many challenges. All materials needed to complete the project had to be transported by helicopter and the site could only be reached on foot via the 500 year old ‘Jumandi Trail’. Difﬁ cult access to the slope face meant that all equipment and installation teams had to be connected to abseil points. Reproﬁ ling the slope was completed gradually, in sections. To stabilise the slope, 220 Platipus B4 Cast SG Iron anchors were installed to a depth of 8m, on a 2m off-set grid pattern, using a core drill rig with mounted compressor. Each anchor was proof loaded to 50kN/5t. In addition, 20 Plati-Drains were installed to a depth of 5m at the top of the slope and 7m at the bottom of the slope to reduce pore water pressure and increase stability. Once the B4 anchor systems and Plati-Drains were installed, 820m2 of HPTRM was placed across the entire slope face and secured in position using load plates and load nuts to complete the installed B4 anchor systems. A further 200 Platipus S2 ARGS Systems were also installed to hold the HPTRM tight to the slope surface to provide erosion control measures and encourage re-vegetation.