Geotechnics links soil and rock mechanics with the planning and execution of structures as well as controlled demolition. It provides the fundamentals to investigate subsoil, assess load-bearing capacity, secure excavation pits, and perform targeted concrete separation/cutting of concrete or rock members. For practice-oriented tasks such as concrete demolition, special demolition, interior demolition and cutting, rock excavation and tunnel construction, or natural stone extraction, it forms the methodological framework: geotechnical parameters determine drilling and splitting patterns, cutting lines, required forces, and the sequence of work steps. This enables the safe and efficient use of methods such as the hydraulic splitting method with hydraulic rock and concrete splitters, the gentle crushing with a concrete pulverizer, or combined cutting and shearing processes.
Definition: What is meant by Geotechnics
Geotechnics encompasses soil and rock mechanics, subsoil exploration, foundation and earthworks, slope stabilization, tunnel and rock construction, as well as the geotechnical part of deconstruction. Central contents include determining material and structural parameters (density, grain-size distribution, consistency, shear strength, stiffness, crack and joint systems), forecasting deformation and failure behavior, and deriving safe construction and demolition methods. In practice, the range spans from dimensioning a pit shoring to planning non-explosive rock removal, and defining separation and crushing paths in reinforced concrete. Tools such as stone and concrete hydraulic splitters or a concrete pulverizer are selected and operated on the basis of these geotechnical insights.
Fields of application of geotechnics in deconstruction and rock removal
Geotechnics structures decisions along the entire life cycle of a structure or rock mass: before intervention, ground data are collected and evaluated; during execution, geotechnical parameters steer the choice between splitting, cutting, gripping, or shearing; after intervention, measurement and observation data serve quality assurance. In concrete demolition and special demolition, it supports defining the separation joint layout, estimating tensile and shear forces in components, and assessing reinforcement ratios—an important basis for using a concrete pulverizer, hydraulic demolition shear, or a concrete cutter. In rock excavation and tunnel construction, it derives drilling and splitting patterns for hydraulic splitter from joint orientations and strengths and minimizes overbreak. In natural stone extraction, bedding and joint planes are used to release blocks with low energy input. For interior demolition and cutting, insights into material heterogeneity help optimally plan cutting sequences, force paths, and the power supply via a hydraulic power pack. Special operations—such as in confined spaces, in sensitive neighborhoods, or underwater—benefit from geotechnically founded procedures with low vibration levels, precise force metering, and controlled fragment size.
Fundamentals of soil and rock mechanics
The mechanical properties of soils (cohesionless, cohesive, organic) and intact rocks (massive, jointed, weathered) govern load-bearing and deformation behavior as well as failure mechanisms. Effective stresses control settlements and shear resistance; porewater-dependent processes such as consolidation influence time effects. In rock, joint spacing, roughness, infill, and orientation shape failure. These parameters are decisive for choosing splitting, cutting, or crushing procedures and for sizing the required hydraulic pressure and drive power.
Shear strength and failure criteria
In soils, a Coulomb-like criterion describes shear resistance via cohesion and friction angle. In rock, splitting- and shear-based failure along joint systems or tensile failure due to local stress concentration occur. Practice-relevant classifications such as RMR or GSI help assess structural quality. For hydraulic splitter, boreholes are positioned to deliberately activate existing weakness zones; in reinforced concrete deconstruction, understanding tension and transverse load paths enables controlled crushing with a concrete pulverizer without unintended load redistribution.
Deformation and settlement
Settlements due to compaction, creep, or consolidation influence the order of interventions. When working near sensitive neighboring structures, splitting and cutting steps are coordinated to minimize vibrations and deformations. Gentle splitting and targeted “biting” with a concrete pulverizer are advantageous in such situations because the introduced energy remains locally confined.
Investigations and exploration of the subsoil
Before starting, layer structure, groundwater conditions, and material properties are in focus. In addition to file and records analysis, borehole drilling with core extraction, dynamic probing and sounding, load plate test and pressure sounding, as well as geophysical methods are used. For existing structures, rebar localization, cover measurements, and compressive strength tests complement the database. These results make it possible to proactively define borehole diameters, hole depths, splitting spacings, cutting lines, and the sizing of the hydraulic power pack.
Boreholes and core extraction
Core quality, RQD, joint frequency, and orientation provide indications of splitting behavior. Drilling and splitting patterns are adapted to these structural features: In massive zones, smaller spacings and deeper boreholes increase the probability of success of the splitting process; along well-developed joint planes, borehole utilization can be reduced.
Assessment of concrete structures
Concrete strength, aggregates, moisture, concrete carbonation, and chloride contamination influence separation behavior. Knowledge of reinforcement geometry shifts cutting and crushing lines to where tools such as a concrete pulverizer can grip effectively. Pre- and post-separations are coordinated so that load redistributions remain controlled.
Planning of demolition and separation works in a geotechnical context
The choice of method follows the boundary conditions: vibration limits, noise control and dust protection, space constraints, water ingress, neighboring buildings, and load behavior. Hydraulic splitting is suitable when tensile failure is to be triggered in a targeted manner and vibrations minimized; a concrete pulverizer is appropriate when reinforcement is present and fragment sizes must be defined. A hydraulic demolition shear, steel shear, and a concrete cutter cover mixed components and secondary demolition; a cutting torch is used for special material combinations.
Vibration and shock control
To comply with limits, measurement concepts (e.g., vibration velocities) are linked to the sequence. Splitting sequences and pulverizer attacks are placed so that energy inputs remain local. Pre-tests on trial boreholes or edge areas help adjust parameters such as pressing pressure and attack times.
Drilling and splitting patterns
Borehole diameter, depth, center-to-center spacing, and edge distance govern the success of the splitting process. In jointed rock, drilling rows are arranged parallel to major joints; in reinforced concrete, reinforcement is avoided or deliberately undercut so that a concrete pulverizer can follow for exposing and biting off the bars. Water management and drill cuttings disposal should be clarified early.
Tools and methods: selection by ground and component
The selection is based on material, geometry, boundary conditions, and target fragment size. Stone and concrete hydraulic splitters activate tensile failure along prepared boreholes and are suitable for massive concrete or rock when low vibration levels are required. A concrete pulverizer is used on reinforced components, foundations, slabs, and bridge components to reduce cross-sections in a controlled way and expose reinforcement. A hydraulic demolition shear, a concrete cutter, steel shear, and a cutting torch complement secondary demolition, especially for embedded parts, sections, and mixed materials. A hydraulic power pack provides the necessary flow rate and operating pressure and is designed for drive power demand, duty cycle, noise emission, and thermal management.
Concrete pulverizer in foundation and bridge deconstruction
For foundations, pile head, and bridge caps, a geotechnically informed sequence supports safe load shedding. First, tension zones are weakened or pre-cut; then cross-sections are reduced with a concrete pulverizer and reinforcement is exposed in a controlled manner. Groundwater level and slope stability are to be monitored; temporary shoring or a relief cut secure the construction process.
Stone and concrete hydraulic splitters in rock removal and tunnel construction
In tunnel construction near sensitive buildings, splitting devices reduce overbreak and vibrations. In natural stone extraction, they enable release along bedding and joint planes with low energy input. Splitting pressures and wedge geometry are adapted to rock strength, joint spacing, and drilling pattern; borehole utilization increases with precise alignment and appropriate hole cleaning.
Hydraulic power pack and power supply
Essential are flow rate, operating pressure, drive power reserve, and thermal management. Hydraulic hose line routing, quick coupling, and protection against mechanical damage influence availability. In emissions-sensitive areas, noise reduction measures are to be planned. Matching the power unit and attachment prevents performance bottlenecks and reduces cycle times.
Occupational safety and permits
Occupational safety is based on hazard analysis, instruction, and suitable personal protective equipment. In hydraulic splitting and crushing, stored pressure, snap-back, flying fragments, and pinch points must be considered. Noise control (noise), low vibration levels (vibrations), dust protection, and water protection must be addressed early. Permit/approval issues should generally be coordinated with the competent authorities; component-related structural analysis must be provided project-specifically.
Hazards in hydraulic operations
- High-pressure media: protect against hydraulic injection via intact hydraulic hose line, safety distance, and suitable protective clothing.
- Holding sequence: secure components against tipping and falling, plan gripping and shoring points.
- Flying fragments: covers, defined safety zones, adjusted splitting and pulverizer forces.
- Energy relief: depressurize before changing tools or disconnecting lines.
- Communication: clear hand signals and exclusion zones, especially in confined spaces.
Environmental and emissions protection
Dust is limited by wet drilling and targeted dust extraction plant; noise reduction occurs through damping, encapsulation, and sequence optimization. Vibrations are reduced by gentle procedures such as splitting with a hydraulic splitter or removal with a concrete pulverizer. Hydraulic fluids must be handled carefully; leaks must be remedied immediately and disposed of properly.
Sustainability and resource conservation
Selective deconstruction, construction waste separation, and the reuse of construction materials lower resource consumption. Geotechnically optimized splitting and crushing strategies reduce overbreak, secondary damage, and rework. Documenting material flows facilitates recycling; short intervention times and low vibration levels improve acceptance in the surroundings.
Calculation and sizing at a glance
Design is guided by material strengths, cross-sectional geometries, and contact areas. In splitting, the induced tensile stress must exceed local tensile strength; borehole spacing, edge distance, and hole depths control stress distribution. In crushing reinforced concrete, pulverizer forces, jaw opening, and gripping strategy are matched to cross-sections and reinforcement ratios. To avoid edge breakouts, loads are increased stepwise and checked in short cycles.
Example parameter ranges
- Borehole diameter for splitting: about 30–50 mm, depending on wedge geometry and member thickness.
- Borehole depth: typically 70–90 percent of member thickness; for through-holes, increase edge distance.
- Hole spacing: in concrete typically 25–50 cm; in rock depending on joint spacing and strength.
- Edge distance: choose to limit spalling; reduce for thin-walled members.
- Concrete strength: typical compressive strengths 20–50 MPa; tensile strength is significantly lower and governs splitting behavior.
- Reinforcement influence: high steel contents favor the combined use of a concrete pulverizer and cutting tool.
Documentation and monitoring
Ongoing control of vibrations, crack monitoring, settlements, and groundwater level increases execution safety. Photo documentation and measurement logs record progress and support adjustment of parameters such as pressing pressure, pulverizer force, and cycle rate. A clean handover of documented component conditions facilitates subsequent work steps.
Typical challenges and practice-oriented solutions
Water-bearing joints or groundwater require adapted drilling and splitting sequences as well as dewatering. Densely reinforced nodes are gradually exposed with a concrete pulverizer before profiles are separated with a steel shear. In confined spaces, sequence, tool weight, and hose routing are planned to ensure safe access and stable working platforms. In sensitive neighborhoods, monitoring and the preferred use of low vibration levels procedures such as hydraulic splitter are effective.