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Site Investigation

Constructive Evaluation has a team of experienced Geo-Environmental specialists, able to provide full Contaminated Land assessments or soil screening as necessary to fulfil the requirements of construction projects and to satisfy the planning process.

Ground Investigation Services

Good quality Ground Investigation is a vital part of any assured, value engineered design. Constructive Evaluation are able to apply a range of investigation techniques to suit the engineering objectives, access constraints and budget for your project.

Our team of specialist engineers and scientists can advise on the most suitable method to suit any project; with experience across different sectors on projects ranging from domestic insurance claims and house builds to major infrastructure design and large commercial developments.

Investigations can be tailored to suit geotechnical and geo-environmental requirements, with exploratory holes utilised to gather data related to both disciplines. For example drilled geotechnical boreholes may be installed with standpipes to allow groundwater sampling. Our specialist technicians are also trained in construction materials testing, allowing a range of disciplines to be covered by one investigation team.

Intrusive investigations are supervised by one of our team of Project Engineering Geologists and Geo-environmental Scientists to ensure that appropriate, concise and high quality data is recovered from site.

Investigation data is displayed on concise logs available in .pdf and .ags formats, with engineering soil and rock descriptions to BS5930. Typically this is followed by laboratory testing, with production of factual and interpretive reports specific to the project requirements.

Our Ground Investigation services are assured by our industry accreditations including ISO9001 and ISO14001; our teams are trained to work across different working environments in the construction industry, including Highways and Rail sites.

Investigation techniques include:

Window Sampling / Dynamic Probing
Completed using tracked or hand held mini rigs, window sampling and Dynamic Probe Testing provides a mid-range soil investigation technique (typically up to 6-8m) which is highly manoeuvrable and can provide several test holes during a single day. This allows the stratigraphy and strength profile of soils to be established.

Tracked window sampling provides lined samples, ideal for contaminated land investigations, as well as Standard Penetration Testing (SPT) capability. Hand held window sampling uses a jackhammer to drive the samplers into the substrate, this technique is particularly suited to restricted access and is usually supplemented by Dynamic Probe Testing.

Cable Percussive Boreholes
Cable Percussion or Shell and Auger drilling is a reliable and cost effective mid to deep range drilling technology, capable of working on a range of soil conditions and supplying high quality soils testing and sampling. This technique is particularly suitable where it is possible that a deep or special engineered foundation will be required owing to anticipated ground conditions or intended loadings. 

Owing to the flexibility of the drilling system, holes can be advanced to depths in excess of 30m and through variable stratigraphy by utilising multiple strings of temporary casing. Cable percussion usually utilises an A Frame type rig, however demountable versions are available where access is restricted.

Trial Pitting
Constructive Evaluation are able to offer hand excavated and mechanically excavated trial pits to satisfy a range of investigation objectives. Hand pitting by or technical staff is typically used where existing foundation construction needs to be established, and to gather shallow samples for geo-environmental screening.

Mechanically excavated pits provide a tool for rapid assessment of shallow soil conditions, up to 4m depth, and are most suited to multiple plot housing developments. Trial pits may also be used to complete insitu testing such as permeability or California Bearing Ratio assessment.

Rotary Boreholes
Where deep range boreholes or penetration of rock is required, rotary drilling techniques can be used to obtain the necessary investigation data, with modern multi-function plant. This method uses percussive sampling to rockhead, with the hole subsequently advanced using rotary coring or drilling. Samples are recovered in plastic tubes for subsequent logging and sampling.