Residential Manhole Stabilization in California

Problem

The city of La Mesa (outside of San Diego, California) had a multitude of manhole issues in their city. Water infiltration was seeping, bleeding, and leaking through the concrete, and this caused other issues like the creation of voids in the soil from water flow. The city was mainly concerned because pipes could burst from unnatural flow of water from one pipe to the next. They hired URETEK to perform a demonstrational repair on one manhole as a trial run of the URETEK process in their city.

Analysis

The test manhole in question had significant bleeding and seeping, and the goal was to stabilize the manhole to avoid pipe failure and infiltration. The city monitored for water flow outside the walls of the manhole and watched for any irregularities at the base. URETEK planned to complete the project in no more than one day by injecting vertically outside the manhole and horizontally from within the manhole.

Solution

On the scheduled day, URETEK began working at 9:30 AM with La Mesa Engineers and analysts present. The URETEK crew decided upon a three-point injection pattern around the manhole. At each of the three points, crews deployed URETEK Deep Injection® (UDI) at five levels down to 20 feet. By stabilizing all around the manhole, URETEK was able to prevent infiltration at all levels while strengthening the foundation soil. URETEK completed the job by 1:30 PM for a job duration of just four hours.

Result

In less than one work day and in a project area of no more than 40 by 30 feet, URETEK successfully stopped the infiltration of water into the manhole. UDI stabilized the surrounding soils at all levels and plugged the eroding concrete that had allowed non-constructed flow of water. UDI also stabilized the soil radially around the manhole out to eight feet in all directions. The speed and efficiency of this job offered compelling evidence to the city of La Mesa that the UDI process could be a viable solution for their widespread manhole problem.

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.

Residential Manhole Repair
Manhole Repair
URETEK crew lays out the UDI injection pattern around the manhole
Manhole Repair
Top-down view of the manhole that URETEK fixed