Restoring stability and access along Southmoor Drive with PROPEX Armormax and MIRAGRID

Overview

A section of Southmoor Drive was closed due to significant erosion. The road sits atop a slope, with a stream running at the base, making the area particularly vulnerable to erosion and slope instability. Since the closure, residents of nearby homes and patrons of local businesses had to take a detour. Additionally, the erosion had become a potential threat to nearby homes.

Challenge

The primary challenge was severe erosion encroaching up to the fence lines of nearby residential properties. The road location on a slope above a stream added complexity, especially as part of the project involved relocating the stream itself. Transporting traditional stabilization materials like rock riprap was logistically difficult and costly due to the road closure. Additionally, the project needed to balance environmental restoration with cost-effective engineering solutions.

Solution

To stabilize the slope and reopen Southmoor Drive, a fill slope was constructed and reinforced using PROPEX^® Armormax^®, a robust system for permanent erosion control and surficial slope stabilization. The system is comprised of high-performance turf reinforcement mat (HPTRM) and earth anchors that work together to resist hydraulic forces and increase the factor of safety.

Approximately 15,000 y² of PROPEX Armormax was installed using B1 anchors with standard spacing. Prior to installation, seed was applied below the mat to promote vegetation growth. PROPEX Armormax is engineered to promote rapid root development and reinforce natural vegetation. This system was selected over traditional materials like rock riprap as it is lighter weight and easier to transport to projects with site access challenges. Approximately half of a container van of PROPEX Armormax is equal to 250 dump trucks of rock riprap. This significantly reduced transportation costs and emissions.

The specification originally called for a competitor's uniaxial grid to be used as secondary reinforcement on steeper sections of the slope, however the project leads were able to value engineer the design using MIRAGRID^® 5XT. This provided significant cost savings without compromising performance. MIRAGRID XT features high strength, high tenacity, and high molecular weight. They are constructed for applications where long-term design strength is necessary.

The installation was successful, and the contractor expressed satisfaction with the technology and appreciated Solmax’s involvement throughout the project. Reopening Southmoor Drive marked a critical first step in the broader revitalization of the area, with long-term goals focused on restoring the surrounding environment, including the cleanup of Fountain Creek.