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Casing Advancement Systems (Symmetrix)

Casing advancement systems, or drilled casings, are today's preferred method for drilling in difficult ground conditions, for example, where there are boulders or loose formations. This page guides you to the right solution based on your requirements.

What is a casing advancement system?

casing advancement system
As much as 90% of the land surface of the earth is covered with loose, unconsolidated material. When drilling in so-called overburden, the conditions are often challenging with risk for collapsing walls, hole deviations, and failure to reach design depth or bedrock. The casing advancement system is comprised of an ingeniously simple method of drilling through overburden while advancing the casing into the hole at the same time. This enables contractors to perform their work faster with higher quality and reduced risk. The system adds value whether the mission is to install foundation, support elements, or simply case the hole in collapsing formation.

How to select a casing advancement system?
The choice of solution depends on several factors, including ground conditions and application. This page describes a complete system solution and different application scenarios, allowing you to select the right equipment from the extensive product portfolio.


Casing advancement systems can be used in a wide range of applications where you need to drill in difficult ground conditions. The following are examples of the most common applications.

Geothermal well drillingGeothermal well drilling
Geothermal heating of houses is increasingly popular due to both economical advantages as well as environmental concerns. Casing advancement systems are often used to drill the holes through the overburden, keeping the hole open during installation of the heat exchange system and minimizing the impact on surrounding structures.

Water well drillingWater well drilling
Water well drilling is common in urban, developed areas where the well must be drilled quickly with minimum impact on the surroundings. Atlas Copco offers a solution that can be used with small, compact rigs (using the DTH drilling method) with excellent results in almost any ground condition.

Pipe roofingPipe roofing
Pipe roofing is a method to pre-reinforce the ground ahead of a tunnel face to ensure that excavation can proceed safely. A steel casing is installed in an umbrella pattern around the excavation line, forming a protective arch under which the tunnel can advance.

Foundation workFoundation work
Stringent demands on productivity, high drilling accuracy, and the ability to drill inclined piles for foundation work make casing advancement systems increasingly popular for both end bearing and friction piles.

Tieback anchors, or ground anchors, are common all over the world. They are typically installed to provide support for slopes or other structures. They can be installed in combination with a retaining wall structure, as individual or systematic support.

Drilling Methods

Atlas Copco casing advancement systems are available in versions for top hammer or down-the-hole (DTH) drilling. The selected drilling method depends on the diameter drilled, depth of the hole, and the driller's preferred equipment.

DTH is a common method used to drill deep holes with great accuracy. It is suitable to use for straight piling or well drilling that requires the high performance needed for drilling large and deep holes. DTH systems are available in the diameters 4 1/2" to 48"
Top hammer
Top hammer drilling is a fast and efficient method for drilling shorter holes, straight or inclined. It is primarily used for smaller diameter holes in overburden drilling, such as anchoring piles or micropiles. Top hammer systems are available in the diameters 3" to 5 1/2".

DTH versus Top Hammer

Casing Types

Permanent casingPermanent Casing
There are different applications where permanent casing is the preferred choice, the most common are water wells, geothermal wells, foundation works, and pipe roofing.
In water and thermal wells the casing is used as a sacrificial element to just keep the hole open. In foundation works, permanent casing can work as bearing structure of the pile, as a sacrificial element to protect the pile against corrosion or just to keep the hole open.

Retrievable casingRetrievable Casing
Retrievable casing is used when the casing is only needed during the drilling process, that is when it is used to keep the hole open during drilling and not used as support in the finished structure.
This is a cost-effective solution for piles and anchoring since the casing is retrieved from the hole and reused.

System Components

Casing advancement systems are available as either a solitary ring bit or as a ring bit set.


The Symmetrix systems are part of a total overburden drilling solution from Atlas Copco. They work well in both DTH and top hammer drilling, and your choice depends primarily on the drilling conditions on site.

Symmetrix - Productivity and Precision

Symmetrix is a versatile solution for overburden drilling where ground conditions are difficult, time is limited, and precision is crucial. Whether used in ground with big boulders, inclined competent layers, or hard bedrock Symmetrix drills until the required depth is reached. The system drills more quickly and accurately than any other method available today. The unique design of Symmetrix provides reliable results, which saves contractors money.