Preparation of Trial Liners. The contractor must win at least 40 cu.m of clay won from the cell excavation and from at least 6-8 different locations in the borrow pit area. The trial liners must be representative of the full depth of clay determined in the borrow pit area. The clays must be mixed, moisture conditioned, spread in 200mm thick layers and compacted until a 1.0m thick liner depth is achieved. The Geotechnical Subconsultant is required to ensure sufficient representative clay has been sourced for the trials and undertake appropriate moisture, density and permeability samples and tests in accordance with the Specification and Australian Standards. The Geotechnical Subconsultant is required to certify all results and submit a report to the Superintendent for approval. The Contractor shall not commence placement of the clay liner until such approval in writing has been obtained from the Superintendent. Between two and four trial liners are recommended so that a number of clay mixture and compaction level options can be analysed, providing the Contractor with more flexibility during the construction of the compacted clay liner. Provision for four (4) permeability tests on the trial liners has been included in the Bill of Quantities. When the mixture(s) of clay identified as passing the permeability requirement have been established and approved by the Superintendent, the Contractor and Geotechnical Subconsultant shall ensure that all clay being used to construct the liner is at least of equivalent quality.
