Overview: In July 2025, during the final infrastructure phase of the Lennar Homes North River Farms project in Oceanside, CA, we faced a “zero-fail” scenario. We had to excavate a 400-foot sewer trench 25 feet deep through solid blue granite—all while operating inches away from a live fiber optic backbone.
The Challenge:
• The Material: Blue Granite bedrock tested at 41,000 PSI.
• The Proximity: A critical fiber optic line was located just 18 inches from the trench wall.
• The Failure of Force: Standard hydraulic hammers on a 75-ton CAT 375 were ineffective and created dangerous vibration levels for the fiber line.
• The Depth: 25-foot target depth with a requirement for a perfectly level 24-inch pipe install.
The Solution:
Rock Busters utilized a non-impact chemical demolition strategy to protect the sensitive infrastructure.
• Tandem Precision Drilling: We used two SmartROC T35 rigs to drill 4-inch diameter holes to 27 feet (2-foot sub-drill). By drilling the full depth from the surface in a single pass, we minimized the time spent near the fiber line.
• Vibration-Free Expansion: We switched to ROCK-XL specifically for its massive expansive force (18,000+ PSI) without the shockwaves of blasting or hammering.
• Overburden Pouring: By pouring the ROCK-XL through 10 feet of dirt into the rock below, we kept the trench “buttoned up,” providing extra stability for the neighboring fiber conduit.
The Result:
• Zero Service Interruptions: The fiber optic line remained fully operational throughout the 5-week project.
• Perfect Grade: Our 27-foot sub-drill ensured a clean floor for Southland Paving to install the sewer main.
• Infrastructure Safety: Rock Busters proved that high-production excavation doesn’t have to be high-risk. Rock Busters: Making the Impossible Possible.
0 Comments