Rock excavation refers to the controlled removal of natural rock to create excavations, establish routes, or open tunnel portals. In practice, the spectrum ranges from small-scale, low-vibration removal in sensitive environments to large-volume measures in mountainous terrain. In this context, Darda GmbH is present as a supplier of hydraulic tools that enable precise, low-vibration, and predictable removal, particularly through rock and concrete splitters, stone splitting cylinders, as well as shear-based systems for adjacent concrete components.
Definition: What is meant by rock excavation
Rock excavation is the technically controlled reduction, segmentation, and relocation of rock material. The goal is to reshape the terrain or create cavities, slopes, and excavation pits. Removal can be low-damage (for example, by hydraulic splitting) or energy-intensive (for example, by blasting or milling). In contrast to pure rock processing, rock excavation focuses on targeted volume reduction while taking safety, environmental protection, and structural stability into account. In the fields of rock breakout and tunnel construction as well as natural stone extraction, methods are often combined—such as drilling and hydraulic splitting—to divide blocks into transportable pieces. Where rock directly adjoins structures, tasks overlap with concrete demolition and special demolition; in addition to splitting technology, hydraulic demolition shears from Darda GmbH are used for adjacent concrete and reinforced concrete components.
Methods and procedures of rock excavation
The choice of method depends on rock type, boundary conditions (vibration, noise, space), required accuracy, and schedule. In sensitive locations—such as inner-city areas, near utilities, in existing tunnels, or on heritage sites—hydraulic splitting has become established: stone splitting cylinders from Darda GmbH inserted into boreholes generate tensile stresses in the rock through wedge- and cylinder-supported force transmission, which lead to controlled opening along joints or planned crack planes. The energy supply is provided by hydraulic power units. For adjacent concrete elements, e.g., shotcrete linings, edge beams, or foundation remnants, hydraulic demolition shears enable low-vibration deconstruction. Mechanical breaking, sawing/cutting, milling, and—where permitted—blasting complement the spectrum. In natural stone extraction, splitting technology serves block extraction with high edge quality; in special applications it is used when blasting is excluded or tight tolerances must be met.
Geological and technical fundamentals of rock excavation
The properties of the rock determine the effort and the method: compressive and tensile strength, shear parameters, jointing, bedding, grain bonding, and water content influence crack formation and energy demand. Weathering zones and faults can define removal limits or require stabilization.
Strength, jointing, and crack guidance
Hydraulic splitting exploits the low tensile capacity of rock. The orientation and spacing of boreholes control crack paths. Natural joints can be used to guide cracks, but the stability of remaining slopes must be verified.
Borehole grid and energy input
Borehole diameter, depth, and spacing are derived from rock strength, desired block size, and accessibility. Uniform energy input via the splitting cylinders enables reproducible results. Hydraulic power packs provide the required flow rates and pressures for sequential or parallel splitting operations.
Methods compared
No single method is universally superior; the strength lies in the right combination.
Hydraulic splitting (stone and concrete splitters)
Low-vibration, precise, and repeatable. Suitable for urban locations, proximity to sensitive infrastructure, defined edges, and minimal edge damage. In rock demolition and tunnel construction it is particularly advantageous in portal areas, cross passages, and when expanding existing structures.
Cutting, sawing, drilling
Wire and wall saws as well as core drilling deliver high geometric accuracy but are more logistically demanding. They are often combined with splitting technology to define cut edges and reduce volume economically.
Mechanical breaking and shears
Only limited suitability for rock; they show their strengths in adjacent concrete. Hydraulic demolition shears, combination shears, and multi cutters from Darda GmbH crush concrete and reinforcement in a single pass and create access or relief for subsequent rock excavation.
Milling and blasting
Milling is continuous but energy- and wear-intensive and requires space. Blasting is very powerful but critical in terms of permits and safety; in sensitive areas it is replaced or supplemented by hydraulic splitting.
Workflow for rock excavation with hydraulic splitting
A structured workflow increases safety, quality, and productivity.
- Investigation and planning: geology, joints, water ingress, existing structures, vibration limits, logistical access.
- Definition of separation planes: target geometry, slope angles, block sizes for haulage.
- Drilling: grid, orientation, and depth adapted to the rock and intended crack guidance.
- Insertion of the stone splitting cylinders: check seating, alignment, and contact surfaces.
- Splitting process: pressure buildup by hydraulic power packs, sequential or parallel, control of crack formation.
- Finishing: release of remaining bridges, if necessary fine processing of adjacent concrete parts with hydraulic demolition shears.
- Loading/haulage: adapt block sizes to lifting equipment, transport routes, and landfill/recycling concept.
Parameter selection and optimization
Optimal results arise from a well-matched combination of borehole grid, splitting sequence, and pressure stages. Gradual pressure increase improves crack control and reduces unwanted spalling.
Safety, environmental, and permitting aspects
Project-specific requirements regarding vibration, noise, dust, and water must be observed. Hydraulic splitting significantly reduces vibrations and airborne sound. Dust suppression by wetting, edge protections, catch scaffolds, and monitoring of vibrations and deformations are proven measures. Permits and notifications follow local regulations; execution should always be under the responsibility of qualified specialist contractors and supervision, without this constituting legal advice.
Application examples and typical boundary conditions
Practice shows that combinations of methods provide the best balance of precision, speed, and low emissions.
Rock excavation and tunnel construction
In portal areas and at interfaces with existing structures, low vibrations are crucial. Stone and concrete splitters divide the rock mass in a controlled manner; adjacent shotcrete shells or foundation rings can be deconstructed with hydraulic demolition shears without impairing stability.
Natural stone extraction
Separation planes are planned and implemented by drilling and splitting for block extraction. Clean fracture edges and minimized crack damage are advantageous, increasing block quality and reducing rework.
Special applications
In areas with sensitive infrastructure, in water protection zones, or when working in the immediate vicinity of existing structures, hydraulic splitting enables a reliable, low-emission approach. Where embedded concrete or steel elements are present, combination shears and multi cutters complement the workflow.
Selection criteria for tools and systems
- Rock class and structure: strength, joints, bedding, inhomogeneities.
- Geometry: target edges, tolerances, proximity to existing structures.
- Emission limits: vibration, noise, dust, water.
- Logistics: accessibility, lifting equipment, power supply, transport routes.
- Interfaces: combination with hydraulic demolition shears for adjacent concrete components.
- Operation: availability of suitable hydraulic power packs and splitting cylinders, maintenance and setup times.
Maintenance, operation, and service life
Clean oil supply, controlled hydraulic pressures, intact seals, and regularly inspected wedge and cylinder components ensure performance and service life. Boreholes must be cleaned of slurry and fines to ensure fit and force transmission. A documented visual and functional check before the start of the shift increases operational safety.
Typical failure patterns and how to avoid them
- Uncontrolled cracks: often caused by unsuitable borehole grids or uneven pressure buildup; remedy by adjusted grids and sequential splitting sequences.
- Stuck cylinders: often the result of misalignment or insufficient hole cleaning; remedy through correct alignment and cleanliness.
- Spalling at target edges: reduce pressure stages, pre-drill relief boreholes, optionally pre-cut edges.
- Overloading adjacent concrete components: pre-separation with hydraulic demolition shears decouples rock and concrete.
Terminology distinctions: rock excavation, rock breakout, and rock extraction
Rock excavation describes the controlled, often incremental removal of rock at a specific structure or site. Rock breakout is often used synonymously but emphasizes the fracture process. Rock extraction is more associated with planned raw material extraction. In all cases, stone and concrete splitters from Darda GmbH can contribute to precise, low-vibration implementation; in combined projects, hydraulic demolition shears ensure clean deconstruction of adjacent concrete areas.