Ground Anchor Systems: Components, Functions, and Installation Guide

Introduction

Ground anchors are essential in construction, drilling, and mining projects for stabilizing soil and rock.

They provide quick and efficient construction while ensuring structural reliability and stability.

Popular systems include:

DYWIDAG’s DYWI® Drill Hollow Bar System, THREADBAR® Anchors, GEWI® Piles,

ISCHEBECK’s TITAN micropiles, and

Epiroc (formerly Atlas Copco) Self-Drilling Anchor rock bolts.

While specifications differ between brands, the principles and overall structure are largely similar.

This article explains the main components of ground anchor systems, their design, installation process, applications, and testing.

Key Components of a Ground Anchor System

1
2
3
4
5
6
1

Anchor Nut

Transfers load to the supporting node.

2

Anchor Plate

Distributes force to the supported structure.

3

Coupler Sleeve

Connects multiple anchor bars together.

4

Centralizer

Keeps the reinforcing element centered in the borehole, ensuring uniform cement coverage.

5

Anchor Bar / Full-Thread Drill Bar

Main reinforcing element.

6

Drill Bit

Breaks rock and soil during drilling.

Ground Anchor System Design

A ground anchor typically consists of three main parts:

  1. The Head – Transfers load to the anchor tie rod.
  2. The Anchor Tie Rod – Transfers load from the head to the root.
  3. The Root Seal – Transfers load from the rod into the ground.

After installation, injection mortar is poured into the cavity. To protect against corrosion, the rod is coated with a special polymer.

A hollow attachment (drill bit or chisel) is placed at the bottom of the pile to facilitate soil penetration, chosen based on soil characteristics.

At the top of the pile is a support plate secured with domed nuts. In most cases, the cap includes a support plate attached to the strapping belt, along with a direct anchor fastening unit (conical washer and nut).

The pile kit also contains centralizers and couplings:

  • Coupler sleeves extend the pile rods
  • Centralizers orient the shaft within the borehole

When Are Ground Anchors Used?

Ground anchors prevent excavation walls from collapsing.

  • Example: A deep pit needs excavation. Sloping walls may not be possible if the site is surrounded by buildings or infrastructure like tram tracks.
  • Solution: Secure the enclosing structure with ground anchors.

Applications of Ground Anchors

Ground anchors:

  • Reduce settlement of surrounding buildings
  • Simplify excavation compared to strut systems

Common applications:

  1. Excavations: Stabilize walls, slopes, and embankments
  2. Foundations: Stabilize tall buildings and bridges
  3. Transport Infrastructure: Roads, tunnels, railways, highways
  4. Hydraulic Structures: Dams, weirs, and water-retaining structures

Types and Fastening of Anchors

Materials used as anchor bolts include:

The anchor root is formed by injecting cement mortar under pressure.

Ground Anchor Installation Process

Required Equipment:

  • Drilling rig
  • Cement injection pump
  • Mixing station for cement slurry
  • Cement storage silo
  • Water tank

1. Drilling and Grouting

Drill to the design depth using a cement slurry with a water-to-cement (W/C) ratio of approximately 0.8.

2. Securing the Anchor and Load Testing

Dynamic well testing is performed using a thicker cement slurry with a W/C ratio of around 0.5 to ensure proper load capacity.

Note: W/C ratio = Water-to-Cement ratio

3. Ground Anchor Testing and Specifications

  • After installation, each anchor must be tested to confirm the design load
  • Only after confirming the load can the anchor be permanently secured (anchor locking)
  • Anchor tie-rod sizes ensure high load-bearing capacity for soil and material
  • Accessories should exceed the design load of bars

Self-Drilling Anchors and Drill Hollow Bars

For self-drilling anchors or drill hollow bars, drilling and grouting are completed in a single step.

This method saves time and is especially suitable for weak soil or rock conditions, increasing project feasibility and efficiency.

Conclusion

Ground anchors are critical in modern construction, civil engineering, and infrastructure projects.

By understanding components, installation, testing, and applications, engineers can ensure stability, reliability, and efficiency even under challenging soil and urban conditions.

Explore our full range of ground anchor systems and accessories—contact us today for technical guidance or an e-catalog.

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