Following the successful completion of the Moorebank Intermodal Demolition and Remediation Early Works Package, Liberty Industrial were awarded the contract to construct the new Moorebank Precinct West Access and Compound civil works package as Principal Contractor for Qube Logistics. The purpose of the works was to enable the access and egress of potentially over 500 heavy vehicle movements per day once the bulk earthworks phase of Moorebank Precinct West gets underway.
Prior to the commencement of works, a suite of management plans, including WHS, Quality Construction, Hazmat and Incident plans, were submitted to the client for approval to ensure the works were to be undertaken to the required standards.
The first stage of the project was to undertake bulk excavation along the entire footprint of the project to ensure the minimum required cover for structural fill underneath the pavement in the specifications was met. Liberty Industrial deployed multiple crews including D7 dozers with GPS, 35t excavator and dump trucks to cart the material to stockpile. In total, there was 4,000m3 of topsoil stripped, and 9,000m3 of general fill excavated.
The team took care to ensure material that looked suitable for re-use was stockpiled separately, and this resulted in the re-use of over 5,000m3 of general fill during the bulk filling works.
Following the bulk excavation works, a 200mm sandstone capping layer was placed and compacted to provide a firm and level base for the High Energy Impact Compaction (HEIC) to be undertaken on the majority of the footprint. HEIC was used in order to meet the strict requirements of the Technical Specifications, as well as to identify any soft spots in the ground due to underlying uncontrolled fill. In total, Liberty Industrial excavated and backfilled over 3,000m3 of unsuitable material and backfilled to the required specifications.
Once the soft spots were remediated, Liberty industrial commenced with bulk filling works using imported structural fill. To avoid double handling of material, the imported material trucks tipped straight onto the work-front where a crew consisting of an 815 compactor, D7 dozer, 20t smooth drum roller and a spotter were stationed to receive, place and compact the fill under Level 1 Geotechnical supervision and density testing. Due to the pro-active approach of constructing an all-weather access road into site, the project was also able to accept imported fill during days of inclement weather, and hence were able to stockpile material to load and cart for placement once conditions improved. In total, over 50,000m3 of structural fill was placed over the project footprint. The final trim was undertaken by a millimetre grader to ensure the placed fill was within the allowable tolerance of 5mm of the design levels.
During the bulk filling works, the team constructed concrete slabs for the weighbridge and the wheel-wash. The team accelerated and prioritised the bulk filling in the areas where the slabs were to be constructed to allow for early construction and use of the weighbridge and wheel-wash.
The DGB20 pavement layer was then placed and compacted as per RMS specification 3051. LI worked with Qube to cart approximately 15,000m3 of crushed concrete from LI’s previous IMEX and PEDR contract at Moorebank Precinct East which passed as DGB20 after being tested by the Geotechnical Consultant, further showing LI’s ability to reduce costs where possible. The pavement layer was then finished with a 45mm layer of AC14 on the trafficable roads, and 10mm prime-seal in the carpark and compound area.
During the works, the team also constructed over 2km of swales and excavated two new basins as per the design to ensure the control of stormwater run-off during rain events. The team co-ordinated the testing with the site’s environmental consultants to ensure the water was below the criteria for contamination before releasing the water into the environment. The team flocked the water if the results failed for turbidity, applied hydrochloric acid solution if the water was too basic, or applied calcium hydroxide solution if the water was too acidic.
Liberty Industrial also undertook numerous variations during the project as requested by the client, the most notable of which was an above ground 3 mega litre basin to hold PFAS impacted water. Thanks to the investigations undertaken during LI’s previous Demolition and Remediation package on the site, the client, LI and all other relevant stakeholders were aware that PFAS contamination in run-off water was prevalent in some areas of site. The site team worked with Qube to come up with the best solution and location to construct the basin, taking into account future development staging plans as well as potential release points for the water once treated. The team constructed the basin with imported sandstone, and once the basin was shaped to design, installed a concrete sump pit connecting to an outlet pipe at the lowest section of the basin. The basin was lined with High Density Polyethylene (HDPE) to ensure the basin was impermeable and also guaranteed the longevity of the basin by protecting it from potential scouring. The individual rolls were fusion welded together, and the liner was kept in place at the top of the basin wall through the use of an anchor trench. Once completed, safety controls were put in place such as a life ring and a role of geofabric material on the shallowest slope of the internal walls to enable ease of access to the bottom of the basin if empty. The team also laid topsoil on the outside batters of the basin for stabilisation, and then placed jute mesh on top of the topsoil.