Rotary Drilling

Rotary drilling is used to collect soil and rock strata samples, or to form deep observation boreholes which are used as part of geotechnical and environmental site investigations.

Rotary Drilling as part of Site Investigations

What Is Rotary Drilling?

Rotary drilling is used to collect soil and rock strata samples, or to form deep observation boreholes as part of Geotechnical and Environmental ground investigations. This is a fast drilling technique used where penetration is required through very dense soils and rock to investigate the sub-surface conditions of a development site. Rotary drilling advances a borehole using impact energy plus rotation.

The drilling rigs can be track or lorry mounted depending on access and the area of the site investigation. The drilling rigs use high levels of torque and rotation to enable the penetration of very dense soil and rock strata. The drill has a rotary cutting head at the end of the drill shaft, which rotates rapidly (50 and 120 rpm) and advances through the ground.

The dual speed and high frequency of rotations mean that this form of drilling can carve through hard rock easily, and softer ground. The rapid rotating cutting heads require cooling down so are lubricated with air, water, or drilling mud, as appropriate. The results of rotary drilling can be used to provide interpretive reports for Geotechnical and Geo-Environmental Ground Investigations for a wide range of services including:

  • Foundation Designs
  • Piled Foundation Solutions
  • Basement and Retaining Wall Design
  • Piling Mat Design
  • Mine workings

Earth Environmental & Geotechnical Ltd. provides a full range of drilling services throughout the UK for Geotechnical and Geo-Environmental Site Investigations.

What Are the Different Types of Rotary Drilling?

There are two main types of rotary drilling, Rotary core drilling, and Rotary open-hole drilling.

Rotary Core Drilling

Rock coring for Site Investigation

Rotary core drilling is used when core samples of rock are required to investigate the structural details and composition of the underlying rock. Rotary Core Drilling is frequently used when a development site may need deep foundations or heavy loadings. The core is brought to the surface for further analysis within the inner barrel using a wire rope or attached line to a recovery tool. The rock cores are carefully extracted, photographed, and stored in wooden core boxes.

The cores are then logged by our experienced geo-environmental engineers in accordance with the relevant British and European standards (BS EN ISO 14688-1 and BS EN ISO 14689-1 )
The samples taken from rotary drilling may be tested on-site or sent for laboratory testing e.g.

  • Unconfined Compression Test -UCS Tests

  • Point Load Tests

  • Standard Penetration tests (SPT)

Rotary Open-Hole Drilling

Rotary open-hole drilling is used when rapid progress is required on projects such as mining investigations. Rotary open-hole drilling is appropriate when the structural details of the rock are not necessarily required, but the presence of voids and depth of rock is required. Rotary open-hole drilling is often used for investigating shallow mine workings etc.

Often gas and groundwater monitoring pipes are installed in the borehole to allow later measurements and monitoring especially if drilling through old mine areas

Rotary Open Hole drilling is an ideal Site Investigation drilling method for :

  • Site Investigations for Mineworkings (coal seams, mine shafts, etc.)
  • Site Investigations for Underground Cavities and Chalk Dissolution Features
  • Site Investigations to locate specific sampling depth in rock
  • Site Investigations for Installation for Gas Monitoring and Groundwater Monitoring in rock
What is Rotary Drilling

Further Information on Site investigations and Ground Investigations

Ground Investigation Intrusive Techniques Examples:

Earth Environmental & Geotechnical have been involved in Environmental & Geotechnical ground investigations for a wide range of developments. Contact us now to discuss your development

All Ground investigations are conducted in accordance with strict and well-defined health and safety practices with site specific method statements and risk assessments provided. Prior to commencement on-site service (gas sewers, electricity etc.) information is acquired from the client (or its agents) with utility tracing conducted, if required.

Many site investigations are conducted to discharge planning conditions and our staff always ensure, time permitting, that prior to delivery of a costed proposal an outline of the proposed works are initially discussed with the regulatory authorities.

Our staff have extensive experience in the design of geotechnical, mining and environmental site investigations in accordance with current best technical practices and planning guidance. The team are able to manage geotechnical and geo-environmental investigations for the most demanding of sites. Our multidisciplined teams include engineers, geologists, environmental scientists, drillers and technicians who are experienced in all aspects of ground investigation and remediation works.

In-house drilling rigs are wherever possible used for drilling work, with approved quality sub-contractors used for projects (where necessary).

Earth Environmental & Geotechnical conduct site investigations in accordance with Eurocodes that were introduced into UK design on 31 March 2010 and has invested in equipment and methodologies demanded by the standards. We ensure that updates and new legislation is adhered to as part of our code of conduct. We however believe that high quality site investigations arise as a result of the design, supervision, monitoring and interpretation process rather than the field equipment used.

What is Rotary Drilling

Call Now to Discuss Your Development Site

Rotary open hole drilling with water based flush

Drilling in Little Hulton as part of the assessment of shallow geology and coal mining regime. The client is proposing to extend a factory unit over an area of suspected shallow unrecorded coal mine workings. Rotary open hole drilling with water based flush. All done under the remit of a Coal Authority permit.

Site investigation on a school in Wigan

Site investigation on a school in Wigan. Assessment of ground conditions for foundation design. Rotary drilling to investigate potential shallow coal mine workings following a Coal Mining Risk Assessment (CMRA).

Deep rotary openhole drilling

Coal mining investigation in Burnley. Setting up two rigs for 40m deep rotary openhole drilling using water flush. Site investigation for extension of factory premises

rotary core drilling

Site investigation on a chemical works in Staffordshire. Rotary coring with standard penetration testing in superficial deposits. Ground information required for design of foundation piles and tower crane risk assessment.

Rotary drilling

Earth Environmental & Geotechnical Ltd. provide a full range of services. Here we are in Barnsley looking for an abandoned coal mine shaft in an area of deep colliery fill.

Rotary Drilling
Follow on drilling from a Coal Mining Risk Assessment (CMRA). Rotary open hole borehole (water flush) being used to assess potential shallow coal mine-workings beneath the development area. All work was undertaken in accordance with a Coal Authority Permit.
rotary rig undertaking an investigation
Rotary Drilling
Trial Pits

Trial Pits

Trial Pits are used for sub-surface site investigations and examination of the soil, rocks and groundwater. Trial pits ideally proceed construction works to determine the geology and the water table of that specific site and are typically between 1 and 4 metres deep.

Cable Percussive Boreholes

Cable Percussion Boreholes

Cable percussion boreholes can be used to investigate the soil profile to a depth of up to 50m. Different cutting head heads are used for different soil types. Chisel for rock and hard layers, a shell for granular soils and a clay cutter for softer cohesive soils.

Windowless sampling drilling rig

Window Sampling

Window Sampling is used on soft ground and cohesive strata to extract soil, clay or sand samples for geotechnical or chemical analysis. Window sampling is a great technique to recover undisturbed samples for geotechnical and environmental analysis.