Combined Percussive and Rotary Drilling

Name: Ruddlesden Geotechnical
Price range: $

Ground conditions, particularly in the South West, often mean that a combination of percussive and rotarydrilling techniques are required.

In situations where softer ground (e.g. clay/ sand) is interlayered with harder ground (bedrock), drilling rigs that are capable of utilising both percussive and rotary drilling techniques are used.

Case Study

Boreholes for Retaining Wall, North Devon

To aid the design of a large retaining wallat a former glove factory in North Devon, Ruddlesden geotechnical were commissioned to undertake a geotechnical investigation to provide information on the ground conditions. Combined percussive and rotary drilling was undertaken, to obtain sufficient samples of the near surface soils and deeper rock materials, which could not be readily sampled using percussive or rotary methods in isolation. Cost (and time) savings were made by only mobilising one drilling rig, rather than have undertaken separate phases of investigation for the sampling of soils and rock materials. Photograph of the completed project, courtesy of the architect – Woodward Smith.