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In this application, the Geobuffer system was implemented on a pipeline crossing a landslide in East Tennessee, USA, in 2023. The site is located on a steep slope with an inclination ranging from 16° to 28°, intersecting a 140 ft long axial-to-oblique landslide. This landslide moves parallel to the pipe on the upper side of the slope and gradually transitions to make a 45° angle with the pipe at the lower part of the slope.
The landslide caused 1.0 foot of displacement between moving and stable ground at the slope's lower side. The bending strain in the pipe was estimated at 0.48% in the area with maximum differential displacement. Initially, remediation involved replacing the affected pipe section, improving drainage, and installing strain gauges on the new pipe segment. After reviewing the site conditions and schedule, the Geobuffer system was added to minimize slide impact on the pipe.
The preliminary scope for the Geobuffer was developed based on the conditions of the landslide and pipeline, which included the installation layout and an approximate evaluation of the improvement in pipe performance under applied displacement. Finite element modeling and analysis of the pipe-soil-Geobuffer interaction verified the effectiveness of the proposed system. The design layout was finalized in collaboration with the geotechnical engineering team, considering the geotechnical parameters. It was also reviewed for construction feasibility and scheduling, in coordination with other project components.
Monitoring sensors were pre-installed within certain Geobuffer blocks to track their deformation and pipe movement. Upon completion of the Geobuffer system and subsequent backfilling, these sensors were integrated with the Remote Monitoring Unit (RMU) to enable remote real-time monitoring of system deformation. The system installation proceeded smoothly, adhering strictly to the planned and scheduled timeline.
The Geobuffer system increased the pipe displacement tolerance from 2.2 ft to 9.0 ft. Installation at this site, despite challenges related to topography, construction space, and schedule, showed that Geobuffer is an effective method to enhance safety and extend the service life of pipelines affected by geohazards.
