Ground improvement encompasses all measures that strengthen soil or rock so that structures can be founded safely and durably. This includes increasing load-bearing capacity, reducing settlements, improving drainage, or enhancing earthquake resistance. In practice, ground improvement often does not start with adding new materials but with creating access: selective deconstruction of existing remnants, profile-accurate rock removal, or opening of excavation pits. Many projects employ concrete pulverizers and hydraulic rock and concrete splitters, frequently powered hydraulically via compact hydraulic power packs. This allows excavation pits, foundation bases, and alignments to be prepared with low vibration levels and enables geotechnical measures to be executed in a controlled manner.
Definition: What is meant by ground improvement
Ground improvement is the systematic alteration of soil and rock mechanical properties to ensure serviceability and structural stability of constructions. Typical objectives are increasing shear strength, reducing settlement tendency, adjusting stiffness, lowering permeability, or purposefully increasing drainage capacity. Depending on the ground, this may include compaction, injection, mixing, reinforcement, drainage, preloading, soil replacement, or controlled shaping and stress relief of rock. In existing structures, preliminary deconstruction is required: concrete foundations, floor slabs, pile heads, or rock outcrops are exposed, separated, and removed. Here, concrete pulverizers enable material-friendly removal of reinforced concrete sections, while hydraulic wedge splitters break massive components and in-situ rock into defined blocks with low vibration, which is particularly advantageous in urban environments.
Objectives, key parameters, and design fundamentals
The design of geotechnical measures is guided by load cases, limit states, and target parameters. Commonly monitored parameters include effective shear strength (c′, φ′), stiffness modulus (E, M), permeability (k), pore water pressure, relative density, void ratio, and swelling rate. Field and laboratory investigations such as CPT, SPT, load plate tests, density measurements, wave measurements, and water sampling provide the basis for design and quality assurance. While safety factors and stability checks govern the ultimate limit state, allowable settlements, differential deformations, and vibration limits are paramount in the serviceability limit state. In rock, the geometry of discontinuities, bedding, and site-specific joint statistics are decisive. Well-documented subsoil investigation and continuous control during execution are integral to any ground improvement.
Overview of ground improvement methods
Numerous methods are available for ground improvement. Selection depends on grain structure, fines content, water content, construction time, environmental requirements, site constraints, and the vibration sensitivity of the surroundings. The following outlines common approaches and links them to practical preparatory works, which are often executed with concrete pulverizers or hydraulic wedge splitters.
Soil replacement and exchange
Unsuitable soils are excavated and replaced with load-bearing material. In existing conditions, this often requires selective removal of concrete slabs, foundation remnants, or fills. Concrete pulverizers separate reinforced elements in a controlled manner, producing a clean excavation pit base. In rocky ground, rock splitting cylinders enable profile-accurate removal without blasting vibrations, preserving the stability of adjacent structures.
Compaction and relative density
Vibro techniques, dynamic compaction, and surface compaction increase the relative density of granular soils. When an excavation pit is prepared beforehand, a low-vibration pre-deconstruction with hydraulic wedge splitters reduces the risk of settlement-induced cracking in neighboring buildings. Processed recycled concrete from deconstruction can—after suitability testing—be reused as frost protection or base layer material, strengthening material cycles.
Injections and solidification
Injections with suspensions or resins can fill voids, reduce permeability, and mobilize reserve bearing capacity. Existing components are often exposed to establish drilling points and injection corridors. Concrete pulverizers create precise openings, while chip-free edges improve control over the injection path. In rock, controlled split contact surfaces provide a defined geometry for grouting packer levels.
DSM and soil mixing methods
Soil mixing techniques introduce binders into the ground and homogenize them. This requires sufficient working height and clear excavation pit edges. Preparatory separation and cutting of existing components and installations are often performed with hydraulic tools; hydraulic power packs supply the required energy, while the low noise and low vibration facilitate work in existing structures.
Drainage, preload, and consolidation
Drains, vacuum consolidation, and preloading accelerate consolidation of cohesive soils. For drain trenches, service crossings, pile heads, or old concrete must be locally opened. Concrete pulverizers and precise cutting tools minimize damage to existing utilities and allow orderly backfilling.
Reinforcement and elements
Geogrids, micropiles, anchors, gravel and vibro-replacement columns increase load-bearing capacity and mitigate deformations. Where steel sections, reinforcement, or sheet piles must be separated, in addition to concrete pulverizers steel shears and combination shears are used to clear the ground for subsequent measures.
Deconstruction and clearance as part of ground preparation
Ground improvement in existing settings begins with the orderly removal of obstacles. In concrete demolition and special demolition, concrete pulverizers enable selective removal of foundations, abutments, or pile heads while simultaneously separating reinforcement. This reduces noise peaks and vibrations compared to percussive methods. In areas with in-situ rock—such as in rock excavation and tunnel construction—hydraulic wedge splitters are used to release rock beds or outcrops along predrilled hole rows in a controlled manner. The result is profile-true excavation pit walls and bases with minimal cracking.
Selective openings and gutting
For building gutting and cutting in existing buildings, precise openings are required for drillings, injections, or drains. Hydraulically powered separation tools supplied by compact hydraulic power packs create access without unnecessarily weakening the structure. Multi cutters and combination shears support the removal of heterogeneous installations, utilities, and profiles.
Special boundary conditions
In sensitive areas—near laboratories, hospitals, or heritage buildings—a low-vibration approach is crucial. Targeted splitting of concrete or rock limits vibrations and secondary damage. For special cases in special operations, a cutting torch can help clear contaminated zones or dismantle tanks to safely carry out subsequent soil mechanics measures. Such activities require heightened care in occupational safety and environmental protection measures.
Low-vibration and controlled working methods
Minimizing vibrations is a key factor in urban environments. Concrete pulverizers transfer forces in a controlled way into the concrete section and limit structure-borne sound. Hydraulic wedge splitters generate line-shaped separation plane systems in rock or concrete via borehole force. This enables predictable block sizes, clear removal sequences, and geometries optimized for subsequent geotechnical works—such as injection curtains or anchor drilling. Combining these with a suitable water spray system and dust suppression further improves working conditions.
Planning, investigation, and quality assurance
Successful ground improvement begins with thorough subsoil investigation. Core samples, soundings, laboratory analyses, and hydrogeological assessments form the basis. Execution and control proceed in defined steps: preparatory deconstruction, creating access, carrying out the geotechnical measure, accompanying measurements, and documentation. Load plate tests, density measurements, trial load tests, and permeability tests serve verification. For rock removal, documenting joints and discontinuities improves forecasting quality for further planning. Changes in the ground, such as water inflow, are addressed in a monitoring plan to adapt the construction method if necessary.
Material cycle, resource conservation, and environment
Ground improvement offers opportunities for a sustainable circular economy. Concrete material obtained from deconstruction can—after suitability testing—be used as recycled concrete aggregate in base courses or as filler. Precise deconstruction with concrete pulverizers facilitates clean separation of concrete and reinforcement. In rock removal, hydraulic wedge splitters allow the recovery of blocks with defined edges, which can favor reuse as riprap or backfill material. Water and dust management, protection of groundwater protection, and low-emission working methods are integral parts of site management.
Safety and legal notes
Ground improvement works are subject to technical regulations and official requirements. Safety and health plans, hazard analysis, and staff qualifications are key. Project-specific measures for noise reduction and vibration minimization, as well as protection of adjacent structures, are defined. Blasting works require a blasting permit; where such methods are not permitted, hydraulic splitting techniques and material-friendly separation methods can be suitable alternatives. The notes are general in nature and do not replace project-specific planning or consulting.
Application areas and typical projects
Ground improvement is implemented in numerous projects: in concrete demolition and special demolition to strengthen existing foundations, in building gutting and cutting to create new shafts and foundations, in rock excavation and tunnel construction for profile-true bench and crown, in natural stone extraction to obtain stable blocks, and in special operations where special boundary conditions such as emission limits or contamination exist. In all these areas, concrete pulverizers and hydraulic wedge splitters create the structural prerequisites for geotechnical methods to be implemented in a targeted, safe manner with high execution quality.
Practical recommendations for high execution quality
Early coordination between geotechnical engineering, deconstruction, and execution teams reduces interface risks. A field test or a sample cross-section helps verify parameters and site logistics. For work in existing structures, vibration and crack monitoring should be provided. Preparatory separation with concrete pulverizers and low-vibration rock removal with hydraulic wedge splitters increase the predictability of subsequent measures. Continuous documentation—from subsoil investigation through deconstruction to quality assurance—is essential for verification and the durability of the structure.