Ground Anchors and Soil Nailing

Sheet Piling (UK) Ltd are able to offer a full range of geotechnical engineering services including ground anchors and soil nails using a modern fleet of hydraulic drilling rigs.

The above services can be offered either as a complete package for an anchored retaining structure or as a stand-alone appointment for specialist geotechnical applications including grouting, CFA piling, rock bolting and facing works.

All site works are supervised and carried out by vastly experienced operatives with the necessary Health & Safety competency cards. Where design works are required these are undertaken using in-house design engineers or experienced external consultants.

Temporary & Permanent Anchors

The main application of geotechnical ground anchors is to prevent horizontal movement and ensure stability of retaining structures including sheet pile, bored concrete pile and steel tubular pile walls. In addition anchors maybe used to prevent additional movement or stabilize existing retaining walls and bridge abutments.

Ground anchors can be temporary or permanent depending on application; can either be "passive" or pre-stressed to 110% of working load post installation; and can be installed inclined or vertical.

Anchor capacities generally range from 100kN to over 3000kN depending upon the ground conditions over the grouted anchor length and the tendon material used.

The following type of geotechnical anchors can be supplied depending on final application:

Temporary anchors which maybe a single grouted self drilling bar or may incorporate a single duct.
Permanent anchors which incorporate full double corrosion protection from grouted and corrugated UPVC ducts to BS8081:1989.
Removal anchors which can be used where there are third party issues beneath adjacent properties.

Typical applications of ground anchors are summarised below:

Structural tensioned support to sheet, concrete or steel pile retaining walls.
To resist hydrostatic uplift forces and anti-flotation for deep structures.
Cofferdams where internally bracing causes construction problems.
Stabilizing and strengthening of existing dock walls / marine structures.
Tie backs to river and canal walls.

Soil Nails

Soil nailing provides a cost-effective solution to many slope stability and earth retention problems. Mainly used on infrastructure widening schemes (highway, motorway and railway earthworks); the system can also be used to re-profile and steepen existing sloping sites where more traditional expensive retaining solutions may previously have been used.

Soil nailing is a technique that works by reinforcing and strengthening the existing ground. Each soil nail consists of a reinforcing bar that is generally made of steel (with full corrosion protection for permanent works) although self-drilling hollow bar soil nails can be installed where soil conditions allow.

Installed from the top down, the slope or required excavation is supported/stabilized by the soil nails being put into tension as the ground relaxes. To ensure no localised slippage of the earthworks face, a facing system is generally required which can comprise sprayed concrete or geo-mesh fabrics as necessary.

Unlike ground anchors, soil nails are generally a "passive" system and are not post-tensioned. However testing to prove the bond capacity at the soil/grout interface is an essential par tof the design process and is generally carried out on sacrificial nails to confirm/verify assumption made in the design.

Typical applications for soil nailing include:

Stabilising/Steepening existing cuttings to maximise development space.
Stabilising of existing over-steep/unstable embankments.
Provide remedial works to existing concrete and masonry retaining structures to ensure long term stability.

Key Benefits and Advantages

Ground Anchors

Economical and practical alternative to propping.
Provides an open excavation.
Can be used in a wide variety of soil conditions.
High loads can be generated.
All anchorages are post-tensioned to 110% working load.

Soil Nails

Need for expensive temporary works is avoided by top down construction.
Adaptable to difficult access sites and quick to install.
Existing cuttings and embankments can be stabilized in economical manner.
Environmentally friendly since trees and vegetation can remain.
Installed using lightweight plant reducing working platform requirements.

Useful Downloads

Photos

Ground Anchors and Soil Nailing