Diaphragm Wall construction for Stage 4 (Project 145) for a fourth Dump Station and associated conveyor infrastructure at the Port Waratah Coal Services (PWCS) Kooragang Coal...
Jet grouting is a soil improvement technique that employs high-speed fluid jets to erode a soil.
Diameters range from 600mm to 2500mm.
Jet grouting is a soil improvement technique that employs high-speed fluid jets to erode a soil. The resulting cavity is then filled with grout to form a composite soil/grout material that enhances the overall properties of the soil.
Ground modification/improvement of a soil by jet grouting plays an important role in the fields of foundation stability, particularly in the treatment of load bearing soils under new and existing buildings. Jet grouting should be considered in any situation where the control of underground fluids or excavation of unstable soils is required.
Jet Grouting installs fluid grouts, (air and water if necessary) at high internally controlled pressures, varying from 30 to 50 mpa (4,300 to 7,200 psi) and relies on high nozzle velocities to achieve the required diameters. As such it has proven popular for both ground improvement and in particular underpinning of existing footings on poor ground conditions.
- Can be installed in nearly all soil types.
- Very quick and precise construction.
- Designable strength and permeability.
- No harmful vibrations.
- Ideal for underpinning.
- Ideal for ground improvement.
Diaphragm Wall construction for Stage 4 (Project 145) for a fourth Dump Station and associated conveyor infrastructure at the Port Waratah Coal Services (PWCS) Kooragang Coal Terminal (KCT).
The work was carried out for Bechtel on behalf of PWCS.
The project included the following relevant elements:
- A dump station which is approximately 15 m deep, 12 m wide and 66 m long. The walls were formed using diaphragm wall construction with a jet-grouted base plug.
A conveyor exits the base of the dump station through a tunnel which slopes up to a surface exit point about 200 m to the east and was constructed using a similar methodology to the main dump station.
Scope of Works
All construction associated with the diaphragm wall system and supporting base plugs (jet Grouting Plug) between the walls for both the dump station and the tunnel.
Dump Station area was divided by cross DW panels into 3 cells. Tunnel area was divided by (Jet Grouting) cross cut-off walls into 4 equal cells.
No. of Cells: 3
No. of Diaphragm Wall Panels: 25
Size of Panels: 11nos.x800mm wide x (2800mm-7000mm) length x 20m-28m depth.
24nos.x640mm wide x (2800mm-7000mm) length x 14m-21m depth.
No. of Cells: 4
No. of Diaphragm Wall Panels: 48
Size of Panels: 48nos.x640mm wide x (2800mm-7000mm) length x 11.3m-17m depth.
- Design and Construct Guide Wall.
- Supply and installation of all concrete, reinforcing steel, hold-down bolts, couplers, embeds and ferrules.
- Supply and installation of Inclinometer pipes.
- Installation of A base block plug (Jet Grouting Plug) throughout both the dump station and the tunnel to limit the inflow of water as specified.
- Jet Grouting Cut-off Walls to separate the Tunnel into 4 sections.
- Water Tightness Testing for all 7 Cells in the dump station and Tunnel.
Concrete used: 40MPa for DW panels (volume 4,673.8m3)
25MPa for Guide Wall (volume 476.2m3)
Reinforcement: 522.75 ton