The blasting effect describes the totality of effects that arise when chemical energy is released abruptly in an explosion. It includes shock waves, gas expansion, vibrations, fragmentation, and thermal as well as acoustic phenomena. In the practice of concrete demolition, special demolition, rock excavation, tunnel construction, and natural stone extraction, the blasting effect determines whether conventional blasting technology is permissible and appropriate—or whether alternative, controlled methods such as hydraulic rock and concrete splitters or concrete demolition shear from Darda GmbH are more advantageous.
Definition: What is meant by blasting effect
Blasting effect refers to the physical and technical impacts of an explosion on materials and surroundings. These primarily include the shock wave (shock front), the gas pressure (heave or throw effect), the brisance (shattering capacity in the near field of the charge), fragmentation (breakdown into pieces), vibrations (ground waves, particle velocities), air overpressure (airblast), thermal effects, and noise emission. In the construction industry and extraction sectors, these effects are decisive for safety, permitability, structural compatibility, and the selection of alternative, non-blasting methods such as hydraulic splitter and shear-based deconstruction.
Action components and influencing factors of the blasting effect
The blasting effect arises from coupling explosive energy into the surrounding medium. Its manifestation is governed by explosive properties (detonation velocity, brisance), charge geometry and coupling, degree of confinement, borehole and stemming conditions, stand-off to the surface, as well as material properties of concrete and rock. Understanding these factors is central for planning, risk assessment, and methodological alternatives.
Physical fundamentals of the blasting effect
Shock wave and impulse
Detonation generates a shock front with a very steep pressure rise. The maximum overpressure and the impulse determine spalling, scabbing, and local shattering. In brittle media such as concrete or hard rock, this leads to radial crack networks and fragment formation.
Gas pressure and heave
After the shock front, hot reaction gases expand. This longer gas-pressure phase causes throw, ejection from boreholes, and large-scale loosening. Tight coupling of the charge to the borehole (e.g., by full coupling) increases energy transfer and thus the blasting effect.
Fragmentation and crack formation
The combination of brisance and gas work generates cracks that lead to fragments. In concrete, reinforcement layers influence the fracture pattern; in rock, bedding, joints, and water content are decisive. Unwanted overbreak occurs when the blasting effect extends beyond the intended area—an essential reason to rely on concrete demolition shear or hydraulic splitter in sensitive environments.
Vibrations and air overpressure
Vibrations are transmitted through the subsoil as seismic waves; the governing metric is peak particle velocity (PPV). Air overpressure (airblast) can affect building envelopes and glazing. Both parameters are often limiting for permits and, in dense urban settings, argue for low-vibration hydraulic methods.
Thermal and acoustic effects
Temperature spikes and noise emission are accompanying effects. For occupational safety and neighborhood protection, noise limits, dust exposure, and visibility impairments matter—aspects that can be reduced by controlled, non-explosive methods.
Blasting effect in concrete demolition and special demolition
In the deconstruction of structures, structural stability, protection of adjacent infrastructure, and emissions control take priority. Blasting effects often have to be drastically limited. In urban situations, near sensitive installations (utility lines, laboratories, hospitals), or with heritage structures, conventional blasting works are frequently not permissible or only manageable with great effort. Here, concrete demolition shear for controlled biting and size reduction of components and hydraulic splitter for low-vibration opening of massive sections are suitable.
Typical application patterns
- Selective deconstruction of foundations and columns with hydraulic splitter to prevent cracks from propagating into adjacent components.
- Removal of slab and wall sections with concrete demolition shear; reinforcement is gripped simultaneously, allowing controlled load transfer.
- Combination with hydraulic power units to supply the tools, matched to drive power and accessibility.
Blasting effect in rock excavation and tunnel construction
In rock tunneling, blasting is common, yet the blasting effect can lead to overbreak, damage at the tunnel face, and vibration issues. Near inhabited areas, in sensitive geology, or in zones with settlement risk, hydraulic splitter are employed as an alternative. They produce directed crack formation with highly accurate fracture surfaces and minimize vibrations and air overpressure.
Precision and geology
Hydraulic splitter enable precise contours, reduce rework, and protect the integrity of the rock mass. This is a major advantage at the tunnel heading, in portal areas, and near existing structures compared to uncontrolled blasting effect.
Blasting effect in natural stone extraction
In the extraction of natural stone blocks, fracture-surface quality is critical. The blasting effect can induce microcracks and reduce block value. Hydraulic splitting acts slowly and in a controlled manner, preserving the integrity of large-format blocks. For subsequent sizing, concrete demolition shear or Multi Cutters in suitable configurations can contribute to dimensionally accurate pre-segmentation.
Planning parameters and evaluation of the blasting effect
For a holistic view, terms and characteristics are helpful without providing operational blasting instructions. In the context of alternatives, these quantities are used to define requirements.
- Brisance and detonation velocity: Measure of shattering in the near field.
- Coupling and confinement: How tightly the charge is connected to the borehole and material; influences energy transfer and fragment throw.
- Distances and geometry: Material thickness, edges, bedding joints; decisive for the propagation of the blasting effect.
- Peak particle velocity (PPV): Assessment metric for vibrations in the neighborhood.
- Air overpressure: Relevant for façades, windows, and sensitive installations.
Occupational safety, permitting, and environmental aspects
Blasting works are subject to strict legal requirements, qualification demands, and permitting procedures. Safety distance, shielding, measurements (ground vibration monitoring, air overpressure), and dust suppression are obligatory elements of a safety concept. Where these restrictions limit or exclude the use of explosives, hydraulic methods—such as with concrete demolition shear or hydraulic splitter—offer an alternative that is often better integrated legally and organizationally, with lower emissions.
Effect control without explosives
The targeted limitation of material effect can be finely metered with mechanical-hydraulic tools. Hydraulic power pack supply hydraulic splitter, concrete demolition shear, hydraulic demolition shear, and Multi Cutters with the required power. This allows components to be opened, separated, or reduced step by step without generating the typical collateral effects of the blasting effect. In steel and composite structures, steel shear provide controlled cutting; in special demolition, depending on the task, tank cutters are also used when thermal or blasting technology is not an option.
Practical criteria for method selection
- Environmental sensitivity: Proximity to existing structures, utility line, traffic, sensitive equipment—argues for low vibration and controlled effect boundaries.
- Material and build-up: Reinforcement density, concrete strength, rock fabric, moisture; influences crack propagation and fragmentation.
- Accessibility and sequencing: Space conditions, load transfer, staged work planning; hydraulic tools enable sequential working.
- Emission targets: Noise, dust, air overpressure; easier to control with concrete demolition shear and splitters.
- Reuse/recycling: Fracture pattern and grain-size distribution affect downstream use; controlled crushing creates defined fractions.
Typical damage patterns due to unintended blasting effect
Undesired side effects include spalling on adjacent components, crack propagation into load-bearing elements, overbreak in rock, fragment throw, and elevated vibrations. A planning switch to hydraulic splitter or the use of concrete demolition shear in edge areas can mitigate such risks, as the energy input is slow and directional.
Measurement and documentation
Vibration measurements with suitable devices and monitoring of air overpressure provide reliable evidence of actions. With hydraulic alternative methods, the measurement effort often decreases; nevertheless, documentation for quality assurance and neighborhood protection is advisable. Documentation of cut and split schemes, load transfer, and disposal supports a compliant project workflow.
Special demolition and particular boundary conditions
In areas with hazardous substance, in critical infrastructure, or under confined conditions, limiting the blasting effect is often mandatory. Tools such as tank cutters, hydraulic demolition shear, or steel shear enable separating interventions without explosive pressure and vibration peaks. This reduces the risk of unexpected secondary effects and facilitates work under protection requirements.
Application reference: products and areas of use of Darda GmbH
The control or avoidance of blasting effect runs as a common thread across several areas: concrete demolition and special demolition benefit from concrete demolition shear and hydraulic splitter for controlled dismantling; building gutting and cutting uses hydraulic demolition shear and Multi Cutters for low-emission separation cuts; in rock excavation and tunnel construction, hydraulic splitter ensure precise fracture lines; in natural stone extraction, block quality is preserved through low-vibration splitting; in special demolition, specialized cutting tools such as tank cutters come into play. Hydraulic power pack are the power source for the tools in all cases.