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Environmental and Geotechnical Construction Services
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Oil & Gas

LNG Liquefaction Soil Stabilization - Southwest

  • LNG terminal expansion including 3 LNG trains, gas pre-treatment unit and loading dock
  • Mass stabilization of over 2.2 M CY of soft dredged sediment and fill soils
  • Over 4.2 M CY excavation and backfilling
  • Pneumatic conveyance boxes, bucket mixing; 5-8 FT depths; UCS-25 PSI in 28 days

ENTACT performed mass stabilization of over 2,275,530 cubic yards of soft dredged sediment and fill soils in preparation for an LNG terminal expansion. In-situ stabilization was accomplished with (16) excavators working atop timber mats and pneumatic delivery of Portland cement via custom-fabricated conveyance boxes; and performed to 8.0 feet bgs under future foundation structure areas and 5.0 feet bgs from finish grade in other remaining areas. All cement-improved soils and sediment achieved a minimum unconfined compressive strength (UCS) of 25 psi.

Prior to stabilization efforts, ENTACT performed site wide clearing and grubbing; construction of board access roads to facilitate cement conveyance to proposed stabilization areas; performance of three field stabilization pilot tests to confirm reagent dosages met a minimum UCS of 25 psi in 28 days; excavation and hauling 925,117 cubic yards of soils and/or pre-stabilized material from 26 distinct cut areas using (10) 40-ton articulated trucks; backfill placement and compaction of over 1,004,708 cubic yards of soil and/or pre-stabilized material within 31 distinct fill areas; stockpiling 28,639 cubic yards of excess pre-stabilized material; installation of reinforced concrete drainage culverts, 36-inch HDPE outflow structure with catch basins and rock filter dam, liquefaction flap-gated outflow structure with headwall and wing walls, and the Facility drainage outflow structure including headwall and wing walls; demolition of 1,117 cubic yards of concrete foundations associated with an old plant/washout pit, existing outfall structure, and concrete supports; removal of 7,000 lineal feet of chain link fence, a 9-foot wide, 61-foot long and 4-foot wide, 26-foot long walkway grating with handrails, and miscellaneous timber and steel beams; and downsizing of 28 piles (HP 10×27) to 2.0 feet below existing grade.

Three LNG Trains (Trains 1 through 3), a Common Gas Pre-Treatment Unit, and a Loading Dock are currently being constructed and connected to the existing facility to complete this turnkey natural gas liquefaction facility now that ground improvement activities are complete.