Horizontal DTH casing advance drilling is most commonly used for underpasses of roads and railways. Drilling is typically called as "break through" drilling. Casings are drilled from starting pit to receiving pit. When casing is advanced to receiving bit, the reaming ring bit is removed and drill string with hammer and pilot bit are pulled back to starting pit.
With DTH hammer it is possible to drill horizontally in complex ground types. It is typical that overburden conditions vary from clay and sand to material with boulders, till and solid bedrock. Sizes vary from 168 mm casing up to 1,5 meters. Hammers that are used are typically undersized to keep the drilling front as light as possible for better accuracy.
Benefits of DTH in Horizontal Drilling
DTH has several advantages while drilling horizontally in overburden:
- DTH drilling can take casing through any ground and solid hard rock
- Spiral Flush air control bit does not push the stones up to surface nor create holes or cavities
- Productivity is high and can always be estimated
- Equipment is easy to transport and set up
- Mobilisation times are short and low cost
- Drilling is accurate
PPV Finland provides a wide range of solutions to horizontal DTH applications. Please contact us for further information.