Anchorage regional landfill-expansion project

Overview 

In 2020, the Municipality of Anchorage’s Solid Waste Services department (SWS) decided to expand its landfill capacity by adding a new cell 9 and tying it to a number of existing cells in close proximity. Alaska Aggregate Products, LLC (AAP) was awarded the geosynthetics and piping contract and chose Solmax to supply all of the required geosynthetics. AAP installed approximately 650,000 ft² (60,000 m²) of a composite liner system for the new cell. The liner composite system consisted of BENTOLINER^® NW Geosynthetic Clay Liner (GCL), 80mil (2mm) double-sided textured GSE^® HD liner and a 16 oz (450 g) cushion geotextile with a HDPE Leachate Collection Piping System. 

Challenge

For this project, a site-specific slope-stability analysis was performed by the engineering firm, Bristol Engineering Services Company, LLC. The specifications called for a GCL material that had already been tested and met the requirements. Bristol required interface-shear testing on the BENTOLINER NW GCL provided by Solmax to ensure that it met all requirements for the site specification, specifically 02078 2.3 C 8: “Interfaces shall have at a minimum a friction angle of 11.5 degrees and a cohesion of 250 psf, or equivalent combination of Mohr-Coulomb strength parameters, across the range of normal loads and displacements tested.”

Solution

Solmax performed all testing and provided all of the data to show that its BENTOLINER NW material exceeded all requirements for the specifications. All testing results were delivered on time and without any impact on the project’s schedule. 

Two significant challenges facing Solmax were the logistics and long lead times of getting materials to Alaska, while also keeping the project on track during those months when Alaska has the most rain. APP took advantage of every good weather day by working longer hours, and deploying as much GCL and liner as possible, in order to complete the job on schedule and within budget. Solmax’s logistics department worked closely with AAP and AAP’s freight subcontractor to schedule and ensure on-time delivery of all materials.