Services - Site Investigation


Amplus is an Associate Member of the Association of Geotechnical and Geoenvironmental Specialists

Amplus is a member of the ECO-ACTIVE BUSINESS environmental accreditation scheme

Amplus drillers are trained  in accordance with  BDA  and CITB guidelines.    

Generally the following site investigation techniques are employed for the majority of projects:
     Trial Pitting 
     Window Sampling and Dynamic Probe Testing 
     Rotary Cored Boreholes
     Rotary Percussive Boreholes

Trial Pitting

Trial pitting can be carried out by a variety of methods from hand dug 
pits to machine excavated trenches. Trial pitting is generally carried out to a maximum depth of 4.5m with standard excavation plant and, depending on soil conditions, is generally suitable for most low rise developments. 

All trial pit investigations are supervised by experienced engineers with a thorough understanding of geology and soil mechanics.

Additional testing in trial pits can include soakaway testing, CBR testing and in-situ strength testing.                    back to top
Window Sampling

Window sampling is carried out by hand held pneumatic samplers.  Window sampling is particularly suited to restricted access sites, contamination investigations, and where disturbance must be kept to a minimum.                                                      back to top


Boreholes are a common method of site investigation. Using a vehicle-towed rig most sites can be investigated. In-situ testing techniques including Standard Penetration Testing, Permeability Testing, Borehole Vane Testing and Packer Testing can all be carried out in the boreholes in order to provide information for geotechnical design. Continuous disturbed and undisturbed samples are retrieved from the boreholes for inspection and logging by engineers and subsequent testing in our laboratories.
Rotary Cored Boreholes

Rotary drilling techniques are employed where boreholes are required into very dense gravel or bedrock. Samples of bedrock are recovered in seamless plastic tubes for subsequent logging by a suitably qualified engineer and for laboratory testing. 
Amplus owns versatile drilling rigs, such as the Fraste Multidrill XL Max rig,  and the Fraste PL rig that can recover high quality core samples in both soil and rock conditions.


Click below to download the following method statements:

More Information on Site Investigation


Site Investigation is undertaken using a light Trailer-mounted Fraste PL rig to undertake borehole ground investigations. This rig permits the recovery of a continuous core sample of soil and rock from the ground surface to completion depth..

A dry core drilling technique, utilizing a tungsten-set cutting tube, is used to penetrate soft materials with d
rilling diameters ranging from 128mm - 84mm. Drilling can be vertical or inclined. Diamond core drilling begins automatically on refusal to dry core drilling giving high quality rock cores. Dry core drilling can be resumed after diamond core drilling, should soft ground conditions recur. The continuous core is ideal for logging, for checking depths, and as evidence of performance.

70 mm diameter sample tubes (U-70) are interchangeable with core barrels, so undisturbed sampling is possible at any depth without reaming out the hole.

Standard Penetration Testing (SPT) can be carried out in the borehole. Down hole testing and instrumentation, gas and groundwater monitoring and sampling, and inclinometer monitoring are all possible.

Field Testing
A range of testing is available including piezometers from groundwater monitoring, magnetic extensometers for settlement measurements and plate load tests.

Laboratory Testing
Geotechnical laboratory testing to BS1377 and analytical contamination testing is undertaken in the UK.

Comprehensive reports including borehole logs and recommendations are available.

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