Casing Advancement Systems

Work faster, safer and with higher quality even in the most challenging ground conditions.

Casing advancement systems, or drilled casings, are the preferred method for drilling in difficult ground conditions. When casing and drilling occur at the same time, the risk of hole collapse is minimized, and you can work faster with better results. Selecting the right kind of system depends on several factors, including the ground conditions and application.

TerraRoc’s casing advancement systems (CAS) have been designed for a wide range of applications to overcome the challenges of difficult ground conditions:

Geothermal well drilling

Geothermal heating of houses are 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 drilling

Water well drilling is common in urban, developed areas where the well must be drilled quickly with minimum impact on the surroundings. In this application the casing advancement systems are commonly used to case the overburden section of the water well.

Pipe 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 work

On the foundation projects its popular to use casing advancement systems for both friction and end bearing piles. The casings can be used as a structural element of the pile or as temporary solution to keep the hole open while installing bearing elements.


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.

Down-the-hole (DTH) drilling and tophammers

TerraRoc casing advancement systems are available in versions for tophammer 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 used to drill deep holes with great accuracy. It is suitable for straight piling or well drilling that requires the high performance needed for drilling large and deep holes. DTH systems are available in diameters 114.3–1219mm.


Tophammer drilling is a fast and efficient method for drilling shorter holes, straight or inclined, primarily with smaller diameter holes in overburden drilling, such as anchoring piles or micropiling. Tophammer systems are available in diameters 76.2–139,7mm.

TerraRoc Casing Types

Permanent casing

Permanent casings are used in water and geothermal wells as a sacrificial element to keep the hole open. In foundation work, they function as the bearing structure of the pile, a sacrificial element to protect against corrosion, or the element to keep the hole open.

Retrievable casing

Retrievable casings are used when the casing is only needed during the drilling process to keep the hole open and not as support in the finished structure. They are a cost-effective solution for e.g. piles and anchoring since the casing is retrieved and reused.

Casing Advancement System Models

TerraRoc offers the following Casing Advancement Systems:


Symmetrix/Elemex for deeper holes, difficult ground, and rock socket projects with casings up to 1219 mm/813 mm diameter. Elemex is ideal for sensitive ground drilling, improving flushing and drilling rates.


ODEX for shallow holes in easy ground conditions using casings up to 273 mm diameter.

Model D

Model D is a plastic casing for blast holes in quarries and mining, suitable for both tophammer and down-the-hole drilling, with adjustable casing length.

What is a Casing Advancement System?


The Casing Advancement System is a drilling method that casing and drilling occurs at the same time. Installing the casing when you are drilling minimizes the hole collapsing risk and enables contractors to perform their work faster with higher quality. The system adds value whether the mission is to install foundation, support elements or simply case the hole in collapsing formation.


Where do we use Casing Advancement System?


As much as 90% of the land surface of the earth is covered with loose, unconsolidated material. When drilling in overburden, the conditions are often challenging with risk of collapsing walls, hole deviations and failure to reach design depth or bedrock.