UDI Supports Jack and Bore Success in Sun Valley, California

Problem

In Sun Valley, California, Los Angeles County officials had a plan to connect two different commercial developments, separated by Arleta Avenue, with a utility expansion project. The project would involve a jack and bore process to install new service underneath the thoroughfare. However, LA County’s prime contractor, WA Rasic, was concerned about poorly compacted and weak soils at the job site. They concluded that the project would likely have a negative impact on the stability of Arleta Avenue’s pavement system, and they knew that full-depth repair was not an option. Before jack and bore work began, and as a purely proactive measure, WA Rasic decided to call URETEK.

Analysis

Working together with the prime contractor, URETEK crews developed a preliminary plan to apply URETEK Deep Injection® (UDI) at the core areas of the upcoming jack and bore work. Next, URETEK conducted Dynamic Cone Penetrometer (DCP) testing to assess the pre-injection soil conditions and confirm the working injection plan. Throughout the planning phase of the project, URETEK worked closely with WA Rasic engineering personnel to confirm the details of a UDI application that would fully stabilize the area and help ensure a successful jack and bore project for WA Rasic.

Solution

URETEK and WA Rasic decided to drill injection holes on three-foot centers. The plan called for one row of injections directly over the targeted pipe location, with two rows of injections on each side of that. URETEK crews installed injection tubes at four depths on the east side of Arleta Avenue, and at five depths on the west side, with the goal of fully stabilizing the area and providing sturdy sub-grade aggregate in which to conduct jack and bore operations.

Result

This unique project demonstrated the effectiveness of UDI as a preventive application when weak soils threaten the long-term success of jack and bore operations. In this case, the prime contractor was willing to take the extra step to ensure overall project success. URETEK stabilized the full area at multiple depths, down to a maximum depth 16 feet. Following UDI, WA Rasic began work on the jack and bore project. The new utility lines were installed successfully to the satisfaction of LA County officials, and there was no negative impact to Arleta Avenue’s paving system, as was originally feared.

URETEK Deep Injection® (UDI)

Widely referenced throughout our industry, UDI involves the injection of structural polymer into base and subgrade soils to increase the load bearing capacity. This is achieved by injecting the polymer through small holes drilled directly through the pavement structure to depths determined by site-specific analysis. Our URETEK 486 Star® material flows easily into voids and weak zones within the soil mass below. Through a controlled chemical reaction, the expanding polymer compacts surrounding soils and applies a controlled pressure on targeted areas of the affected pavement above. If needed, a multi-injection design plan is utilized to gently return the pavement to its original grade. The composite material quickly cures into a strong, dimensionally stable, and water-resistant geo-material, providing years of reliable service.

URETEK 486 Star®

URETEK 486 Star® polymer is a two-component, high-density, expanding thermoset polyurethane system. It was developed to be the ideal solution for under-sealing, void filling, lifting of settled pavement, stabilization and stiffening of weak soils, and for encapsulating and sealing buried infrastructure. URETEK 486 Star® is environmentally inert, non-toxic, and resists underground water erosion or weakening due to its industry-leading hydrophobic properties.

Arleta Avenue
UDI on Arleta Ave
URETEK crews preparing for UDI on Arleta Ave. in Sun Valley
UDI on Arleta Ave.
Only one lane was closed, allowing traffic flow to continue