Deep basements
Multi-level basement excavations on tight urban plots where internal propping would obstruct excavation and substructure works.
Anchoring Division
Apex installs tie-back ground anchors that retain deep excavations and keep the working area clear of props. Drilled on rake, grouted, stressed to design load and proof tested — in single or multiple layers.
Anchoring division quick facts
Anchoring division — quick facts
| Service | Tie-back ground anchors for retaining deep excavations |
|---|---|
| Arrangements | Single layer and multiple layer |
| Installation | Drilled on rake, anchor placed, grouted, then stressed to design load |
| Strand | PC strand wire to ASTM A416/A416M-98 Grade 270, 15.24 mm nominal diameter |
| Anchor heads | 3, 4, 5, 6, 7, 8, 12 and 16 hole, 60 mm thick |
| Load cell range | 0–10 000 kN, 1% full-scale precision |
| Areas served | All seven emirates, from workshops in Al Aweer and Ajman |
Method
Hold the wall from behind, not across the hole
Ground anchors are structural elements that transmit load from a retaining structure into the ground. On a deep basement, they replace internal propping: the load goes backwards into competent strata instead of across the excavation.
Apex installs anchors at a prescribed angle to the horizontal using a tracked anchoring rig — drilling to the specified depth, placing the tendon, grouting the bond length, then stressing up to the design limit once the grout has gained strength.
- Anchors in single layer — one row, typical of shallower retained heights
- Anchors in multiple layers — successive rows installed as excavation advances downward
Sequence
How an anchor goes in
Design review
Anchor load, rake angle, free length and bond length come from the shoring designer. We confirm plant access, working platform level and the drilling method suited to the strata.
Drilling on rake
The anchor hole is drilled at the specified angle below horizontal using a tracked anchoring rig, cased where the ground requires it.
Placing the anchor
The strand tendon is placed to the design depth, with the free length sheathed so that only the bond length transfers load to the ground.
Grouting
Cement grout is injected to form the bond length. The grout is left to gain strength before any load is applied.
Stressing
Once the grout has cured, the anchor is stressed with a multi-strand jack against the anchor head and locked off at the design load.
Proof testing and monitoring
Anchors are proof loaded and readings taken through a load cell and digital indicator. Where the design calls for it, load cells are left in place for monitoring during excavation.
Specifications
Anchor components and capacities
Supplied from stock through the Apex trading division.
PC strand wire — ASTM A416/A416M-98 Grade 270
| Nominal diameter | Steel area (mm²) | Weight (kg/1000 m) | Min. breaking load (kN) | Min. yield (kN) |
|---|---|---|---|---|
| 15.24 mm (0.6 in) | 140.0 | 1102 | 260.7 | 234.6 |
Anchor head dimensions
| Description | Thickness (mm) | Diameter (mm) |
|---|---|---|
| Anchor head, 3 hole | 60 | 115 |
| Anchor head, 4 hole | 60 | 115 |
| Anchor head, 5 hole | 60 | 115 |
| Anchor head, 6 hole | 60 | 135 |
| Anchor head, 7 hole | 60 | 135 |
| Anchor head, 8 hole | 60 | 170 |
| Anchor head, 12 hole | 60 | 185 |
| Anchor head, 16 hole | 60 | 185 |
Load cell — type PRE10000/0/120
| Property | Value |
|---|---|
| Nominal capacity | 0 – 10 000 kN |
| Outside diameter | 189 mm |
| Bearing ring outside diameter | 153 mm |
| Overall height | 120 mm |
| Measuring system | Strain gauges |
| Precision | 1% full scale |
| Resolution | 10 kN |
| Operating temperature | −30 °C to +60 °C |
Applications
Where anchoring is used
Shoring wall support
Contiguous pile, secant pile, diaphragm and sheet pile walls requiring lateral restraint as the excavation is taken down.
Retaining structures
Permanent and temporary retaining walls where load must be transferred into competent ground behind the structure.
Questions
Ground anchoring questions, answered
What is a tie-back ground anchor?
A tie-back ground anchor is a steel tendon installed at an angle behind a retaining or shoring wall and bonded into competent ground beyond the failure wedge. Once grouted and stressed, it holds the wall back against the pressure of the retained soil, allowing a deep excavation to be opened without internal propping.
Why use anchors instead of internal props?
Anchors transfer the load behind the wall rather than across the excavation, which leaves the working area completely clear. On a basement job that means plant can move freely, excavation is faster and the substructure can be built without working around a forest of struts.
What angle are tie-back anchors installed at?
Anchors are installed on a rake below horizontal, at an angle set by the shoring design. The angle has to carry the bond length past the active failure wedge into competent ground while staying clear of adjacent structures and services.
Are anchors permanent or temporary?
Both are possible. Most anchors on UAE basement projects are temporary — they hold the shoring wall while the substructure is built, then are de-stressed once the permanent floors can carry the load. Permanent anchors require additional corrosion protection to the tendon.
Do you need permission to install anchors under a neighbouring plot?
Yes. Anchors frequently extend beyond the site boundary, so agreement from the adjoining landowner and the relevant authority is required before installation. This should be resolved at design stage, because it can decide whether anchoring is viable at all on a tight urban plot.
Enquiry
Get an anchoring price
Send the shoring layout, retained height and anchor loads from your designer and we will come back with a method and a price.
- Prefer to talk
- +971 4 320 4120
- apex@eim.ae
Reach us directly
Call, WhatsApp or email — all three reach the same team, and we reply within one working day.
Call +971 4 320 4120WhatsApp +971 55 221 9418Email apex@eim.aeSite owner: set NEXT_PUBLIC_FORM_KEY to enable the enquiry form.