Specialised service
Geotechnical engineering & ground anchorage
Subsurface analysis, retaining structures, rock and soil anchors, and slope stabilisation — engineered against measured ground behaviour and proven by test.
Why it matters
Most structural risk is decided below the ground line
A frame can be redesigned in a week. A failed slope, an under-capacity tieback or a settlement crack after handover cannot. ARN treats the ground as a structural element with its own investigation, its own design case and its own test evidence — before the first foundation is poured.
Where ground data is thin, we say so and price the investigation that closes the gap. We do not carry an unmeasured assumption into a design.
- InvestigationBoreholes, SPT, CPT, rock coring, groundwater observation
- LaboratoryClassification, shear strength, consolidation, compaction
- AnalysisBearing capacity, settlement, slope stability, liquefaction screening
- DesignFoundations, retaining systems, anchorage, drainage
- VerificationOn-site testing, instrumentation and monitoring
Anchorage systems
Ground tiebacks, soil nailing & rock anchors
Selection follows the ground, the load path and the design life — not the equipment on the yard.
Ground tiebacks (anchored walls)
Pre-stressed strand or bar anchors drilled through a retaining face into competent ground beyond the failure wedge, then grouted, stressed and locked off. Used to hold deep excavation walls, quays and bulkheads with minimal internal bracing so the excavation stays open for work.
- Free length isolated with sheathing; bond length grouted into stable strata
- Double corrosion protection for permanent anchors
- Lock-off load set from measured wall movement, not a default value
Soil nailing
Closely spaced passive bars grouted into a cut face as it is excavated in lifts, creating a reinforced soil block. Faced with shotcrete over mesh or with a drained facing where the cut is permanent. Efficient on staged slope cuts and widening works where access for large plant is poor.
- Top-down installation in 1–2 m lifts, matched to stand-up time
- Pull-out tests on a percentage of nails to confirm bond
- Weep drains and drainage composite to keep pore pressure down
Rock anchors & dowels
Resin or cement-grouted bars and strand anchors into rock to resist uplift, overturning and sliding — for retaining structures, foundations under wind or seismic uplift, and stabilisation of jointed rock faces.
- Discontinuity mapping before layout, so anchors cross the joint sets that matter
- Bond length designed on rock–grout and grout–tendon capacity
- Mesh, dowel and shotcrete combinations for rockfall protection
Slope retention & stabilisation
Full slope treatment — regrading and benching, gabion and reinforced-earth walls, anchored bulkheads, surface protection and the drainage that keeps them working through the monsoon.
- Stability analysed for drawdown, saturated and seismic cases
- Toe protection and scour checks where water is present
- Instrumented slopes where movement history is uncertain
Verification
Anchor testing — what we test and what you receive
An anchor is only worth its test record. Every ARN anchorage package is handed over with the loads, the movements and the acceptance criteria written down.
| Test | Applied to | Load | What it proves |
|---|---|---|---|
| Investigation / sacrificial | Pre-production anchors on a new site | To failure or to design ultimate | Actual bond capacity of the strata before the layout is fixed |
| Performance | Selected production anchors | Incremental cycles to 1.33 × design | Load–extension behaviour, elastic and residual movement |
| Proof | Every remaining production anchor | 1.33 × design load | The installed anchor holds its design load with acceptable movement |
| Creep / extended creep | Anchors in clay, weak rock or long design life | Held at test load | Movement per log cycle of time stays within the specified limit |
| Lift-off | Anchors after lock-off, and during service | To seated load | Retained pre-stress over time |
Acceptance criteria are set per project from the governing specification and stated in the method statement before testing begins.
Delivery sequence
How a geotechnical package runs
Desk study & aerial capture
Existing records, geology, terrain model and drainage read from the drone survey before anyone mobilises a rig.
Investigation
Boreholes and in-situ tests positioned on the model, sampling and laboratory schedule, factual report.
Design & method statement
Analysis, anchor or retention layout, corrosion protection, drainage, test regime and acceptance criteria.
Execution & proof
Installation in lifts, testing to specification, instrumentation readings, signed records in the handover file.
Have a slope, a deep cut or a settlement problem?
Send the location and any existing soil data. We will tell you what investigation the site needs before anyone talks about anchors.