Our Solution Helped Complete Sewer Main Replacements in Challenging Terrain when Nothing Else Worked
Our Client
Our client is a leading commercial and utilities contractor in Southern California. The company has a long-standing reputation for successful projects for over 30 years and works with many city and county municipalities. The project was for a city municipality replacing a main city sewer line in a wet, forested area.
The Problem
The sewer line was installed near a stream in a wet and densely forested area. The proximity to water caused the soil to be saturated and led to complications. When the company was backfilling the new 24” diameter PV pipe, the weight of the 10 feet of soil it was buried under would cause deflection or “pancaking” of the pipe. This would ultimately prevent the sewer pipe from being effective and cause clogs and backups of the entire sewer system.
The Geobear Solution
The company explored several options and found them to be ineffective. One of the most promising options would have been to backfill the sides of the pipe with gravel and backfill with concrete. This solution still posed the risk of the gravel not stopping the deflection and the concrete adding to the weight of the soil.
The expert team from Geobear performed a full site investigation and discussed solutions to stabilize the ground around the pipe and densify the soil. Collaboratively, Geobear technicians and engineers were able to work with the contractor to determine a plan for increasing the load-bearing capacity of the soil.
Our deep injection process was able to densify the soil around the pipe and encapsulate the pipe. Geobear technicians drove injection tubes along the pipe based on our engineers’ specifications, injecting polymer at specified depths and volumes to densify the ground without adding weight to the soil.
Results
Geobear’s proprietary geopolymer injection method created a 3D soil matrix that glued itself together, increasing the load-bearing capacity of the soil around the pipe. This prevented the pipe from having to hold all the weight itself, which is what caused the deflection or “pancaking”. The operation proved to be successful and the pipe passed all of the local municipality’s required inspections.
