LANDSLIDE TECHNOLOGY
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West Africa Pipeline and Gas Facility Landslides

West Africa
Flowslide affecting a jetty pad and pipeline routesFlowslide affecting a jetty pad and pipeline routes
Natural gas development is occurring off the West Coast of Africa. The facility owner was expanding the plant when reactivated ancient landslides affected construction of the primary gas delivery system between the offshore gas field and the fractionation plant on the island.  The plant is situated on a volcanic terrace and dense jungle masked ancient landslides that formed the bluff above the island’s shoreline.

Landslide Technology was retained to provide landslide stabilization expertise.  Fast-track geotechnical services to mitigate slope stability concerns included investigation, mitigation design, and construction.  Investigation at the remote jungle site included land and aerial reconnaissance, evaluation of existing and new geotechnical data, ring-shear strength testing, planning supplemental explorations, instrumentation monitoring, landslide modeling, and stability analyses. 

Landslide Technology quickly recognized the geologic origin and mechanics of the landslides, which allowed mitigation design to be conceptualized quickly and confidently.  Multi-discipline group sessions were held at company headquarters and onsite to address mitigation options and select those that helped keep overall plant construction on schedule.  The alignment of the primary pipelines was modified to fit the landslide mitigation measures and to reduce the length of pipeline on the active landslide.  While modified pipeline components were being manufactured and shipped from the U.S., the onsite earthwork team faced significant challenges to regrade the slope and stop movements within the two months available.  Most of the mitigations utilized materials and equipment available onsite and locally.  Retaining wall construction was accelerated using prefabricated wire mats shipped from the U.S.  An international dewatering firm installed horizontal drains and vertical pumped wells.  Landslide Technology provided construction management of mitigation measures and prepared a manual for operation and maintenance.  The construction of the gas delivery/reinjection pipeline was successfully completed and placed into service. 


Services Provided:

  • Landslide hazard management and planning
  • Geologic reconnaissance of landslide areas
  • Site investigations by borings and test pits
  • Landslide instrumentation
  • Landslide hazard mapping
  • Slope stability analyses
  • Evaluation of appropriate remedial options
  • Cost comparison of remedial options
  • Final design of selected remedial measures
  • Technical assistance to owner during construction
  • Buttresses and retaining walls
  • Home
  • Landslides
    • Hydropower >
      • Bull Run Flume
      • Swift Powerhouse
      • Frog Lake Dam Slide
    • Transportation >
      • Hwy 101 Johnson Creek
      • Looking Glass Hill Slides
      • SR 87 Arizona Slide
      • Togwotee Pass Road
      • Scoby Hill Landslide
      • Wrangell Airport
      • Snowbasin Access Road
      • Beartooth Debris Flows
      • Three Capes Scenic Loop Landslide
      • Richardson Hwy Slide
      • Bonners Ferry Landslide
      • Light Rail Station
      • Skagway Submarine Slide
    • Natural Resources >
      • West Africa Gas Pipeline
      • Greens Creek Mine Road
    • Private Clients >
      • Wasco County Landfill Landslide
  • Rock Slopes
    • Hydropower >
      • Biscuit Rock Rockslide
      • Skagit River Rockfall
      • JC Boyle Canal Rockfall
      • Prospect Dam Rockfall
      • Iron Gate Dam Rockfall
      • Cougar Dam Rockfall
    • Transportation >
      • I-15 (D3) Rock Slope Mitigation
      • Ketchikan Third Avenue
      • US Hwy 2 Libby Rockfall
      • Banks - Lowman Hwy
      • SR 191 Rock Cut Design
      • Going-to-the-Sun Road
      • SR 12 Rockfall Mitigation
      • Lakeside Rockfall
      • US 2 Badrock Canyon
      • South Tongass Highway
      • Weeksville Rock Bolting
      • US 26 Cove Palisades
  • Specialty Services
    • Geotech. Asset Mgmt. >
      • Montana Rock Slope Asset Mgmt. Program (RAMP)
      • Alaska Geotech Asset Mgmt
      • Ohio Landslide Inventory
    • Rope Access
    • 3D Modeling
    • Dam Safety & Slope Stability
    • Const. Sequence Modeling
    • Geotechnical Instrumentation
    • Construction Engineering
    • Expert Witness
  • Staff
  • Resources
  • Careers
    • Geotechnical Engineer
  • Contact Us