Microtunneling Through Rock? Here’s What You Need to Know About Best Utilizing Excavator Splitters For Microtunneling

Microtunneling has become a go-to trenchless rock breaking technique for installing underground pipelines in urban and sensitive environments. But what happens when your microtunnel path hits solid rock?

At Rock Busters, we’ve seen it all— from itty-bitty-tight sites, to tough timelines, with even tougher ground conditions. When you’re dealing with hard rock during microtunneling, using an excavator splitter can make the difference between a stalled project and a smooth breakthrough.

Let’s break down just how exactly to handle the rock encountered during microtunneling (the right way)—and why the excavator splitter is the tool you will want in your corner when you encounter it.

The Problem with Rock During Microtunneling

Microtunneling machines are quite powerful, but if you hit granite, basalt, or high-strength concrete — even the best cutter heads can slow down (or suffer damage). So what are the risks to your project?

• Delays
• Increased wear and tear on your equipment
• Blown budgets
• Safety concerns (ouch)

That’s where controlled rock breaking with the experts comes in.

Enter: The Excavator Splitter

An excavator splitter is a hydraulic device designed to break rock with controlled force. Unlike blasting, which requires permits and comes with safety risks and vibrations, an excavator splitter is quiet, safe, and precise.

Here’s how it works:

1. Drill small-diameter holes into the rock (usually around 1.5–1.75 inches).
2. Insert the splitter’s wedge into the hole.
3. Activate the hydraulic force, causing the rock to fracture from the inside out.

The result? Large pieces of broken rock that are easy to remove, without disturbing surrounding soil, utilities, or the tunnel line.

Why It Works So Well for Microtunneling

Microtunneling requires precise alignment and minimal ground disturbance. The excavator splitter fits the bill perfectly:

• No vibration: Won’t shift soil or damage nearby infrastructure.
• Controlled fracturing: Allows you to remove just enough rock to get the job done.
• No explosives needed: Skip the red tape and keep your crew moving.
• Fits tight spaces: Works in confined shafts and launch pits.

Some Real-World Experience

On one of our recent microtunneling support jobs, a contractor hit hard limestone just a few meters into the launch shaft. Instead of pausing to wait for permits to blast or burning through cutter heads, they called us in – saving time and their project budget.

We drilled a series of shallow holes—only 3–4 inches deep—and used our excavator-mounted splitter to fracture the rock in place. Within hours, they were back on track.

The splitter didn’t just save the timeline—it protected their equipment and kept the site safe.

Tips When Facing Rock in Microtunneling

1. Plan ahead: If your geotechnical report hints at bedrock, make sure to line up a rock splitting solution early (AKA – have a plan B prepped and ready to go!).
2. Use shallow holes: Products like Rock-X as an expansive demolition grout or mechanical splitters can be used effectively with 3″ deep holes.
3. Stay in control: Controlled splitting keeps ground pressure stable—crucial for trenchless projects.
4. Call in the pros: At Rock Busters, we specialize in on-site rock breaking using non-explosive, excavation-ready solutions. If you need help or have a question about your job – feel free to give us a call for advise! We are always here and happy to help.

Starting a Microtunneling Project? Let’s Break Rock—The Smart Way

Whether you’re tunneling under a city street or through a remote hillside, rock doesn’t have to be the end of the road. With the right tools and crew, it’s just another part of the job.

Do you need help breaking rock safely and efficiently on your microtunneling project? Reach out to us! Contact Rock Busters today. We’ll bring the power—without the blast.