Special foundation engineering

Special foundation engineering comprises methods used to found, secure, or selectively deconstruct structures in or on the subsoil. It combines geotechnical engineering, pit shoring, and controlled material removal. Wherever massive elements of reinforced concrete or rock must be adapted, opened, or removed, precise, low-vibration tools and static separation methods are used. In this context, concrete pulverizers as well as rock and concrete hydraulic wedge splitters are frequently deployed which, in combination with suitable hydraulic power units, operate reliably even under confined and sensitive boundary conditions. For users in concrete demolition, tunnel construction, underpinning, and natural stone extraction, special foundation engineering provides robust solutions – from the excavation pit to selective deconstruction.

Definition: What is meant by special foundation engineering?

Special foundation engineering refers to the entirety of methods for constructing, securing, and modifying structures in the ground and on massive existing structures. These include, among others, pile foundations (bored pile foundation, micropiles), diaphragm walls, sheet pile walls, ground improvement (injection method, high-pressure injection), pit shoring (anchors, soil anchoring, shotcrete), underpinning as well as the controlled demolition of concrete and rock elements. A central aspect is the minimization of vibration, noise emissions, and overall emissions, especially in inner-city locations, in sensitive industrial areas, and in tunnels. Static separation techniques such as the hydraulic splitting of rock and massive concrete, as well as the targeted crushing and breaking of elements with concrete pulverizers, are suitable for this. In environments with explosion protection requirements or limited ventilation, non-sparking, low-vibration approaches maintain process reliability.

Core processes and construction principles in special foundation engineering

In special foundation engineering, forces and construction stages are controlled to ensure load-bearing capacity, serviceability, and safety at every phase. Methods differ by objective (founding, securing, separating), medium (soil, rock, concrete, steel), and mode of action (static, dynamic, thermal, hydraulic). Selected principles:

• Load transfer into the subsoil: Bored piles and micropiles transfer loads into competent layers; anchors stabilize excavation pits and slopes.
• Edge formation and tightness: Diaphragm walls or secant pile walls secure excavation pits, reduce groundwater ingress, and enable deep excavation pits.
• Ground improvement: Injection method, soil anchoring, and high-pressure injection increase shear strength and tightness of the subsoil.
• Selective deconstruction: Hydraulic wedge splitters and concrete pulverizers separate elements in a structured, low-vibration manner with high dimensional accuracy.
• Monitored sequencing: Temporary states are checked via measurements and adjusted to keep deformations, settlements, and water ingress within permissible limits.

Clear interface definitions between subsoil, structural elements, and construction equipment support reproducible results and reduce rework.

Methods and procedures at a glance

Pile foundations and underpinning

Bored piles, micropiles, and underpinning secure new structures adjacent to existing buildings. When exposing pile heads, shortening piles, or creating connection details, concrete pulverizers are established for the selective removal of concrete cover and the gentle exposure of reinforcement. If the element concrete is very thick or a high-performance concrete (HPC), rock and concrete hydraulic wedge splitters are additionally used to drive cracks in a defined way and split cross-sections in a controlled manner. Pre-scanning reinforcement, respecting minimum residual embedment, and avoiding bar notching improve durability and load transfer at the interface.

Pit shoring

Diaphragm walls, sheet pile walls, and soil anchoring walls stabilize temporary and permanent excavation pits. For embedment into rock or when tying into existing structures, rock wedge splitters can purposefully build up material stresses to open precisely without explosives (non-explosive rock removal). For reinforcing steel, steel shears or multi cutters are used for separation and sorting. Where connection tolerances are tight, defined drilling patterns for splitters and a staged cutting sequence limit overbreak and protect neighboring structures.

Ground improvement and sealing measures

Injections (cement suspensions, silicates) or high-pressure injection methods improve load-bearing capacity and tightness. If injection bodies, caps, or test fields must be removed again, concrete pulverizers facilitate material-friendly deconstruction, while suitable hydraulic power units ensure a consistent energy supply. Trial areas with documented curing and quality checks help verify target parameters before area-wide execution.

Tunnel and rock construction

In urban tunnel construction and at portal areas, low-vibration methods are in demand. Rock and concrete splitters generate high static forces in the borehole and split rock in a controlled manner, which reduces emissions and protects neighboring structures. In tunnel heading areas or for profile corrections, the combination of splitting technology and concrete pulverizer supports precise shaping; here, hydraulic rock and concrete splitters provide reproducible results with minimal disturbance. Consideration of ventilation, permissible vibration velocities, and access logistics ensures safe and continuous operations.

Material separation and deconstruction in special foundation engineering

The targeted separation of concrete, rock, and steel is part of many construction stages – whether creating openings, removing pile heads, or during refurbishment. Decisive factors are precision, process reliability, and low vibration levels. Dimensional accuracy at interfaces accelerates subsequent trades and reduces remedial work.

Concrete pulverizers in selective demolition

Concrete pulverizers crush concrete by compression and tension, expose reinforcement, and enable controlled reduction of elements. They are suitable for concrete demolition and special demolition, building gutting and cutting, as well as adjustments in tunnels. Advantages include fine controllability, limited fragment size, and reduced noise compared with percussion tools. Optimized jaw geometry and consistent hydraulic supply support fast cycling, clean rebar exposure, and homogeneous fragment grading for recycling.

Rock and concrete splitters for massive elements

Hydraulic splitters operate statically: via wedge or cylinder systems, high spreading forces are transferred into boreholes. In this way, thick foundations, abutments, diaphragm wall heads, and rock benches can be separated without blasting. This technique is particularly suitable in sensitive environments with strict vibration and noise requirements. Defined drilling patterns, adequate hole cleaning, and correct wedge alignment ensure predictable crack propagation and minimize collateral damage.

Additional tools working in concert

• Rock wedge splitter: For deeper split lines and large cross-sections.
• Hydraulic shear and multi cutters: For flexible separation tasks on mixed cross-sections and for separate processing.
• Steel shear: For reinforcement, beams, and structural steel during deconstruction.
• Cutting torch for tanks: For special operations on vessels and hollow bodies, for example on underground tanks in existing structures.
• Core drilling and saw cuts: For controlled pre-cuts, service penetrations, and high-accuracy terminations before splitting or pulverizing.

Hydraulic power packs: energy supply and process stability

Hydraulic power packs supply concrete pulverizers, splitters, and shears with defined pressure and flow rate. In tight excavation pits, shafts, or tunnels, compact units with efficient cooling and good sound insulation are in demand. Important criteria are adjustable performance, robust hydraulic connection, reliable filtration, and operational safety under varying load peaks. Correct matching of power pack and tool increases service life, working speed, and reproducibility of results. Depending on boundary conditions, electric drives can reduce on-site emissions, while load-dependent controls and remote monitoring improve energy efficiency and availability.

Geotechnical planning and construction stages

Every measure is preceded by subsoil investigation, structural analysis, and construction monitoring. Soil parameters, groundwater, settlement behavior, and the interaction between structure and subsoil determine methods and sequence. During deconstruction or breakthroughs, temporary load paths must be considered. Monitored construction stages with measurement concepts (e.g., settlement levels, tilt, ground vibration monitoring) support safe execution. Method statements, risk assessments, and digital as-built documentation enhance transparency and facilitate approvals.

Vibration and noise protection

In densely built areas and with heritage structures, low vibrations and reduced noise emissions are crucial. Static splitting technology and the use of concrete pulverizers help maintain limits and protect neighboring structures. Pre-condition surveys, continuous monitoring, and adapted working windows complement technical measures such as tool selection, damping elements, and optimized advance rates.

Dewatering and environmental aspects

Groundwater lowering, waterproofing, and the handling of process waters must be carefully planned. Water-bound dusts, fines, and flushings must be captured and disposed of professionally. The goal is to minimize inputs into soil and water through suitable environmental protection measures. Turbidity control, separation of fines, and compliant discharge routing reduce environmental impacts and support permit compliance.

Fields of application and typical uses

• Concrete demolition and special demolition: Removing pile heads, opening diaphragm wall heads, deconstructing abutments. Concrete pulverizers and hydraulic wedge splitters enable a controlled sequence with low edge risk.
• Strip-out and cutting: Selective removal of load-bearing and non-load-bearing elements, creating wall openings, rebar cutting with steel shear and multi cutters.
• Rock excavation and tunnel construction: Profile corrections, niches, and cross-passages. Splitters reduce vibrations; concrete pulverizers work on linings and concrete segments.
• Natural stone extraction: Gentle release of blocks along natural joints using splitting technology; low crack formation and good block quality.
• Special operations: Work in ATEX zones, with restricted ventilation, or in highly vibration-sensitive environments. Static separation methods and cutting torch for tanks are considered here.

Process chain: from removal to further utilization

After separation come sorting and logistics. Coarse size reduction with concrete pulverizers, separating reinforcing steel with steel shear, bundling, and haulage. Clean separation joints reduce rework, facilitate recycling, and improve construction waste separation by material streams. On-site processing and documented material flows strengthen circularity and can shorten transport distances.

Quality assurance and documentation

Construction-accompanying measurements, photo documentation, protocols on vibrations, noise emissions, and water management, as well as approvals for construction stages, are common. In deconstruction, markings of separation cuts, evidence of material separation, and weigh tickets substantiate compliant execution within the waste management chain. Pre- and post-condition surveys, calibration records for measurement devices, and maintenance logs for hydraulic tools contribute to traceable quality.

Practical tips: tool selection and procedure

1. Element analysis: Check strength class (concrete/steel), reinforcement, material thickness, restraint, and accessibility.
2. Method combination: Use hydraulic wedge splitters for crack initiation, then concrete pulverizer for edge formation and exposing reinforcement; steel shear for clean steel removal.
3. Match hydraulics: Adapt working pressure and flow rate of the hydraulic power pack to the tool; pay attention to temperature and filtration management.
4. Sequencing: Secure load paths, keep sections small, remove from top to bottom, monitor and document.
5. Control emissions: Apply dust suppression, collect water, perform ground vibration monitoring, and use noise control measures and low-noise time windows.
6. Readiness: Inspect wear parts, keep critical spares available, and plan access routes for safe tool changes.

Legal and safety notes

Work in special foundation engineering requires qualified planning, suitable protective measures, and compliance with relevant regulations. Hazard analysis, briefings, and an adapted construction emergency plan are advisable. Requirements from authorities and clients, for example on vibrations, noise, or groundwater lowering, must be checked project-specifically. Confined space entry, hot work on tanks, and operations in ATEX areas require specific permits and supervision. The information in this text is general in nature and does not replace binding consultation.