Structural Soils operates 26 varied boring and drilling rigs and has direct access to more than 50 additional drilling rigs thorough our sister companies. Our in-house resources include over 60 accredited drillers with appropriate NVQ Level 2 qualifications and CSCS skilled worker cards.
Our comprehensive fleet includes cable percussion, track and truck mounted rotary drilling rigs and window and dynamic sampling rigs suitable for virtually any application, including difficult access and restricted headroom drilling.
Our services include:
Complementary services include a full range of in-situ testing, including
- Standard penetration and borehole vane testing
- Variable head permeability testing
- Packer testing
- Instrumentation and monitoring
Expanding our capabilities further are our wide range of sister companies and long standing and trusted subcontractors, offering services such as downhole borehole logging, dilatometer testing, pressuremeter testing, pumping testing, and seismic testing.
Cable percussive boreholes Back to list
Cable percussive boreholes are the most common method of ground investigation in the UK. A Land Rover tows the rig then winches it onto the borehole position. Where there are low-headroom or access limitations, a modular or demountable percussive rig is available. The company has various rigs, including scaled-down versions of a standard towed tripod or modular rigs that we transport in sections on a trailer and assemble the component parts at the borehole location. We have experience of constructing boreholes to depths of more than 70 m using heavy-duty rigs and a range of casing sizes between 150-mm and 300-mm diameter.
- Various including Dando 2000, 2500 and 3000
In-situ borehole testing techniques include standard penetration testing, permeability testing, borehole vane testing and packer testing, which allow our engineers to provide information for geotechnical design. Engineers retrieve disturbed and undisturbed samples from the boreholes for inspection, logging and subsequent testing in our laboratories. We can install groundwater and ground gas standpipes or instrumentation in the boreholes as part of a long-term monitoring programme.
Rotary boreholes Back to list
We employ rotary drilling techniques where boreholes are required in very dense gravel or bedrock. Our rigs are capable of investigating mineral workings, drilling inclined (angled) boreholes and working in restricted access areas. Samples of bedrock are recovered in seamless plastic tubes for subsequent logging and photographing by a suitably qualified engineer. Samples of rock may then be subsampled for laboratory testing. Rotary drilled boreholes are also capable of undertaking in-situ testing and can be installed with instrumentation.
- Comacchio GEO 205 – small track-mounted multipurpose drilling rig capable of carrying out a variety of drilling techniques, making it a compact ground investigation rig
- Comacchio MC 300 – track-mounted rotary unit capable of carrying out a variety of drilling techniques
- Comacchio MC 405 – track-mounted capable of carrying out a variety of drilling techniques including wireline
- Comacchio GEO 601 – larger version of the Comacchio MC 405
- Comacchio GEO 602 – larger version of the Comacchio MC 405
Window/dynamic sampling Back to list
Window sampling uses either track-mounted or hand-held hydraulic percussive samplers and involves driving cylindrical steel tubes into the ground using a percussive hammer. Window sampling is particularly suited to restricted access sites, contamination investigations and where disturbance must be kept to a minimum. The track-mounted equipment is also capable of carrying out standard penetration testing and dynamic probing.
When sampling, samples are retrieved in seamless plastic tubes for logging and photographing by our suitably qualified engineers. As with the rotary and cable percussive boring, these boreholes can be installed with instrumentation.
All our window and dynamic sample rigs have the capability to undertake dynamic probing
- Geotool – a small versatile dynamic probing rig, capable of window/window-less sampling. Easily transported in a van and can be stripped down to a hand portable state
- Dando Terrier and Lightweight Dando Terrier – a small track-mounted soil-sampling rig designed to carry out rapid, relatively shallow ground investigations for geotechnical and geoenvironmental assessment
- Archway Competitor Dart – similar to the Dando Terrier, capable of dynamic probing
Dynamic probing Back to list
Dynamic probing involves driving a steel cone vertically into the ground using a hammer and the operator recording the number of blows for each 100 mm of penetration. Several versions of the test methodology are available, the usual being ‘super heavy’.
The test provides a continuous profile of ground resistance with depth and is therefore able to locate boundaries between strata of differing density and driving resistance. The dynamic probing results may be used to establish the subsurface presence of obstructions such as old foundations or buried objects. The results can also be used to identify soft areas and voids or cavities within the soil, such as makeup of embankment fills, dissolution features in chalk or mine workings.
Our in-house resources are also capable of undertaking hand boring and Mackintosh probing. Both these techniques are ideal if shallow surface soils need to be investigated, particularly in areas of restricted or limited access.
Concrete coring Back to list
Concrete coring is the process of drilling or cutting through concrete floors, walls and ceilings. Often if our rigs are working within a restricted environment, the concrete is removed using concrete coring. The cores can then be subject to a description by our engineers and in some instances laboratory testing, should the slab be required for reuse. The information obtained on the concrete cores can assist with the preliminary designs.
Our teams have also been asked to perform coring on masonry bridges or stone façades of historic houses to ascertain their makeup.