Tunneling
Tunneling
Tunneling through hard rock is one of the most demanding tasks in civil engineering and mining. Whether you’re advancing a new tunnel, enlarging a cross-section, driving adits, or creating shafts and caverns, breaking solid rock in confined spaces adds complexity, risk, and cost. Traditional methods like blasting and breaking can be disruptive, heavily regulated, and difficult to use safely.
At Yamamoto, we provide a proven alternative with our hydraulic rock splitter. Engineered for precision, safety, and productivity, our technology makes it possible to tunnel through hard rock quickly and cost-effectively, especially in sensitive or confined environments where blasting is restricted or impractical.
What is tunneling?
Tunneling is the process of creating underground passages through competent rock formations for transport, utilities, mining access, or hydropower. Unlike open rock excavation, tunneling brings added constraints: ventilation, overbreak control, ground stability, and strict limits on vibration, noise, dust, and flyrock.
Common methods include:
- Drilling and blasting – productive in certain geologies but often restricted due to vibration, overbreak, and safety requirements underground.
- Mechanical breaking – hydraulic breakers or roadheaders
- Chemical expansion agents – low impact but generally much slower and less predictable for continuous headings.
The challenges of breaking hard rock in tunneling
Working underground introduces unique hurdles:
- Confined spaces & safety – flyrock, fumes, and overbreak control are critical challenges when people and equipment are close to the face.
- Vibration limits – strict vibration thresholds near sensitive structures, existing tunnels, or rail corridors often prohibit blasting.
- Ventilation & dust control – managing air quality and visibility is harder underground; high-impact methods compound the problem.
- Programme risk – slow progress at the face delays every subsequent activity, driving up cost and extending possession windows.
- Overbreak & profile accuracy – poor control increases support costs and compromises the design cross-section.
How Yamamoto Rock Splitter help with tunneling hard rocks
Yamamoto hydraulic rock splitter offer a non-explosive, low-vibration solution ideally suited to underground works. Two counter wedges are inserted into a pre-drilled hole, and the hydraulic cylinder drives a central wedge between them, forcing the rock apart from the inside.
How it works for tunneling:
Yamamoto Rock Splitter is designed for flexible application, and can be used horizontally in a tunneling project:
Drilling
- Create a free face by drilling slots in the centre, bottom and periphery.
- Then, drill split holes between slots, including drilling overlapping holes as bridges between the holes allow the rock to maintain its structural integrity.
- Special attachment on the jumbo boom may be required for slot drilling
- See image for recommended drilling pattern
Splitting
- Mount splitter on a customized carrier equipped with a telescopic boom and rotator, we recommend using Yamamoto Arm-System YTB-1120.
- Start splitting the holes closest to the free face by inserting splitter wedges into the holes. Aim at working from the bottom and up to allow support from gravity.
- Split in 3 steps:
- First, insert half of the total length of the wedge and split.
- Second, further insert ¾ of the total length and split again.
- Finally, insert full length of wedge and split again.
Secondary breaking and mucking
- Work along the cracks caused by the splitter, use a hydraulic breaker mounted on a conventional excavator to break out the cracked rock.
- Use mucking method that suits each project, typically done with a standard excavator.
Benefits of Yamamoto Rock Splitter for tunneling
- Low vibration & noise – protect adjacent assets (rail, utilities, existing tunnels) and improve worker safety and comfort.
- Controlled profile – reduce overbreak to cut support and shotcrete costs and achieve the designed cross-section.
- High productivity – faster than mechanical breaking in hard rock, with predictable cycle times.
- Safer underground operations – no explosives, no flyrock, and no blasting fumes; simpler ventilation management.
- Cost-effective – reduce reliance on blasting teams, roadheaders, or oversized breakers.
- Versatile – effective for headings, portals, adits, cross-passages, cavern enlargements, and shaft sinking.
- Environmentally friendly – minimal dust and no chemical residues.
With decades of global experience, Yamamoto is the world leader in hydraulic rock splitting, trusted by contractors for underground works where control, safety, and efficiency matter most.
Tunneling FAQs
In vibration-sensitive or confined environments, hydraulic rock splitter provide a safe, non-explosive alternative. By applying controlled splitting forces in pre-drilled holes, you can advance the face efficiently with minimal disturbance.
Yes. Many contractors use Yamamoto splitter for profile trimming, cross-passage breakthroughs, night possessions, or zones where blasting is prohibited—complementing drill-and-blast elsewhere.
Productivity depends on geology, hole pattern, and equipment. In hard, abrasive rock where breakers struggle or blasting is restricted, splitter often achieve higher net advance with fewer stoppages and simpler safety procedures.
Yes. Because fractures are induced along a planned hole pattern, splitter help you maintain the designed tunnel envelope and reduce unnecessary overbreak and support costs.
Absolutely. With the YTB-1120 arm-system and compact HRB units, you can position the splitter precisely in tight confines, enabling efficient breakthroughs and enlargements.
Depending on the size of the wedges, drill holes are between 4-5 inches and spaced between 2-5 ft. Your Yamamoto representative can advise on patterns for your geology and tunnel profile.
No explosives and no combustion gases. Dust is limited to drilling and mucking operations, which are managed through normal underground ventilation controls.