Soil anchoring is a central element for structural stability, load transfer and controlled workflows on construction and deconstruction sites. Wherever excavation pits are secured, rock faces stabilized, concrete components separated or heavy components moved, ground anchors reliably transfer tensile forces into soil or rock. In combination with hydraulic tools such as concrete demolition shears and hydraulic rock and concrete splitters, they enable safe cutting sequences, prevent uncontrolled movements and hold components in position until separation work is complete. This applies to concrete demolition and special demolition as well as rock excavation and tunnel construction, natural stone extraction and precise operations during strip-out and cutting or in special operations.
Definition: What is meant by soil anchoring
Soil anchoring refers to temporary or permanent systems that transfer tensile forces into the subsoil or into rock. A ground anchor typically consists of an anchor head, a free length (load introduction path), a bond length with an injection body (grout or resin), anchor steel (bar, strands or hollow bar) as well as corrosion protection. Load transfer occurs through bond and shaft friction between the injection body and the surrounding soil or rock. Soil anchoring stabilizes retaining walls, pit shoring, slopes and structural elements, or secures components during separation and demolition work, for example when forces are deliberately introduced using concrete demolition shears or stone splitting cylinders.
Methods and systems of soil anchoring
Common systems include cement-grouted permanent and temporary anchors (strand and bar anchors), rock anchors, micropiles with tensile function, soil nails and self-drilling anchors. They act as tie-back anchoring (e.g., for excavation pits), as hold-down anchors against uplift, as tension piles or for slope stabilization. Selection and sizing depend on the ground, loads, durability requirements and construction sequence.
Applications in concrete demolition and special demolition
In deconstruction, anchors are used to hold components during cutting, to stabilize shoring, and to transfer loads from demolition and auxiliary structures into the ground. Especially when using concrete demolition shears, reaction and vibration forces arise which, without sufficient tie-backs, can lead to cracking, edge spalling or unwanted movements. When splitting massive components in a controlled manner with stone and concrete splitters, securing the surroundings is also essential: ground anchors reduce the risk of buckling of remaining cross-sections, hold column heads in position and enable defined working joints.
Typical use scenarios
- Tie-back of bracing in excavation pits during the demolition of foundations.
- Temporary securing of wall panels or columns before they are removed with concrete demolition shears.
- Guying of auxiliary masts, guide rails or beams on which hydraulic attachments are guided.
- Load transfer for slab openings made during strip-out and when cutting openings.
Soil anchoring in rock excavation and tunnel construction
Rock anchors stabilize loose rock zones, shingled layers and overhanging sections in the context of rock demolition and tunnel construction. When rock is opened using stone and concrete splitters, anchors installed in advance can secure control faces, define shear planes and retain loose material. In tunnel construction anchors serve for crown and face support, as a temporary measure until lining is installed, or as part of the permanent load-bearing structure. The interaction between anchor tensile forces and stresses induced by split cylinders requires careful design of bond lengths in competent rock.
Natural stone extraction: Stabilization of benches and blocks
In natural stone extraction, rock anchors improve the stability of quarry benches and prevent tipping movements. In combination with stone splitting cylinders, separation joints can be formed in a targeted manner without destabilizing adjacent layers. Ground anchors also serve as lifting points for the safe handling of large blocks until lifting equipment takes over.
Special requirements for strip-out and cutting
When cutting openings in walls and slabs or separating additions, components often have to be secured against tilting and sliding. Temporary ground anchors create defined holding points that take the reaction forces from wire saws, core drilling systems and concrete demolition shears. Low deformations under load are important so that cuts remain to size and no restraint forces are transferred to adjacent components.
Planning and design
Planning is based on ground investigations, load assumptions, construction stages and the anticipated duration of use. For design, characteristic resistances of soil or rock, shaft friction values, base pressures and partial safety factors are used. In addition to ultimate capacity, serviceability (settlements, creep behavior, prestress losses) and durability must be considered.
Relevant load cases
- Tensile forces from shoring and bracing systems, e.g., for excavation pits.
- Reaction forces from hydraulic tools such as concrete demolition shears, combi shears or multi-cutters.
- Dynamic components from splitting operations with stone splitting cylinders.
- Environmental actions such as wind, water overpressure or uplift.
Geometry and anchoring ground
- Free length for elastic elongation and reliable prestressing.
- Bond length in competent layers for safe load transfer.
- Inclination and orientation to minimize lever arms and edge distances.
- Spacing between anchors to avoid overlap of bonded bodies.
Execution: from drilling to tensioning
- Drilling with a suitable method (rotary, hammer drilling, double-head), adapted to soil/rock.
- Cleaning the borehole (air/water flushing, brushing) to ensure bond values.
- Placing the injection material (cementitious grout or resin) and the anchor element.
- Curing under documented conditions, observing minimum waiting times.
- Prestressing to the target force, checking elongations and seating the anchor head.
- Protecting the head area (sealing, caps) and making the connections to walers or girders.
Quality assurance and testing
To verify load-bearing capacity, suitability and acceptance tests are used, e.g., pull-out tests with test loads above the service load. Installation parameters, injection quantities, curing times, prestressing forces and creep behavior are documented. Test plans depend on project size, risk class and the importance of the anchors for temporary structural stability.
Materials, corrosion protection and durability
Depending on exposure, corrosion-protected strand and bar anchors, sheathed systems or double corrosion protection solutions are used. Reduced protection measures may suffice for temporary anchors; permanent anchors require greater effort. Crucial are adequate cover, tight caps and controlled handling of chloride-containing media, for example during the deconstruction of industrial plants.
Tie-back anchoring and hydraulic attachments
Hydraulic attachments such as concrete demolition shears, stone and concrete splitters, combi shears, steel shears, multi-cutters and tank cutters generate forces that are transferred into auxiliary structures and ultimately via ground anchors. hydraulic power units provide the drive power, while soil anchoring provides stability. Important for the construction process: low-friction deflections, backlash-free connections and clearly defined prestress states so that tools work precisely and components are separated to size.
Typical failure modes and remedies
- Insufficient borehole cleaning: leads to low bond – remedy by standardized flushing and brushing procedures.
- Bond length too short: incomplete load transfer – adapt design to ground parameters.
- Missing or insufficient prestressing: excessive deformations – provide tensioning records and re-tensioning.
- Corrosion risk at the anchor head: leakage – tight caps, controlled grouting solutions.
- Overlap of bonded bodies: mutual weakening – plan sufficient anchor spacings and staggered rows.
Occupational safety and environmental aspects
Safe site processes require coordinated lifting and rigging equipment, controlled tensioning and testing procedures, and protected areas during pull tests. For the injection material, ensure low-dust, low-emission handling, avoid leakage and dispose of properly. Noise control and vibrations are reduced by suitable drilling and injection methods; when working with concrete demolition shears and splitters, defined cutting and splitting sequences help limit energy input.
Standards and verifications
Planning, design, execution and testing are aligned with recognized technical rules and project-specific requirements. These include geotechnical verifications, ultimate capacity and serviceability verifications, scopes of testing, as well as documentation of installation and tensioning operations. For international projects, the locally applicable guidelines and approvals apply.
Practice-oriented notes for site execution
- Integrate with the cutting and splitting concept: anchor first, then cut or split.
- Allow for prestress losses: account for creep and relaxation during the construction process.
- Provide measurement points: monitor elongations and displacements, define limits.
- Removal of temporary anchors: clarify early whether pulling, cutting off or backfilling is intended.
- Clarify interfaces: closely coordinate drilling crew, injection, tensioning team and operators (e.g., for concrete demolition shears).