John Moroney Correctional Centre - Miracell® Geocell

Project Background

John Moroney Correctional Complex, an Australian minimum security prison complex for males and females, is located in Berkshire Park, 5 kilometres south of Windsor in New South Wales. In 2018 a new state-of-the-art Shooting/Rifle Range was opened for police officers. The rifle range is designed to provide specialised firearm training for recruits and prison officers in NSW. This outdoor range is remote from other activities and surrounded by natural barriers such as small hills to prevent encroachment, ensure privacy and to assist in noise insulation.

Problem

The slopes of the firing range were built to approximately 45 degrees with a compacted inner core. Following heavy rain experienced in Sydney earlier this year, some localised failures occurred on the slopes at this facility. These if unattended, could lead to more problematic failures, such as a major slope failure in the future.

Solution

The initial design was for a 200mm geocell on the slopes of the firing range. The geocell is used to hold growing media to establish a grass surface on the steep slopes. The contractor contacted Global Synthetics for an alternative solution. The proposal was very conservative causing problems for the contractor. Consequently, we enlisted the services of Geoinventions to provide a preliminary design including installation details. The design was refined to meet project requirements and changed so the installation method would suit the site topography.

After some consultation the designer selected Miracell® 150mm to hold the soil material on the surface. Tendons were selected to support the Miracell®. Cellular confinement systems —also known as geocells—are widely used in construction for erosion control, steep slopes, channel protection, and structural reinforcement for load support and earth retention. Geocell products are three-dimensional, expandable panels made from high-density polyethylene (HDPE). The Miracell® panels have perforated cell walls which are expanded and held into position by either pins or tendons. This ultimately facilitates a free-draining system that keeps materials in place and prevents mass movements by providing confinement of the soil.

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Result

The contractor was able to benefit from the refined design and installation procedure to suit the steep slopes on this project. Following the success of Stage 1 the facility decided to upgrade the other 2 firing ranges shortly after. The Miracell® panels were filled by blowing in a soil mix containing grass species and irrigated.

Miracell® advantages:

• The cellular configuration allows for effective protection and resistance to downward migration of slope materials due to hydraulic flow events.

• the cell is very effective at retaining soils within the cell structure in applications of cut slopes and where the natural cut materials cannot support vegetated slopes

The completed 45 degree slopes have endured very heavy rain events with little erosion damage thus far.

If you have a similar application or looking for solutions to slope erosion or stability issues get in contact with us at Global Synthetics. We have a team of engineering staff who can provide technical advice and preliminary designs for your next project.