Details
Concept were the main site investigation contractor for projects carried out for BBMMJV (Balfour Beatty Mott Macdonald Joint Venture) on the AREA 4 Highways Agency MAC Framework.
Concept were required to complete a ground investigation around the busy M20 Junction 10A, using cable tool and rotary techniques on fields and an area of landfill.
The works comprised:
- 13 No. rotary boreholes with depths between 10m and 20m with associated with sampling, in-situ testing and groundwater measurements.
- 2 No. hand excavated trial pits to maximum depths of 1.2m.
- 12 No. machine excavated trial pits to maximum depths of 4.5m.
- 5 No. Dynamic Cone Penetrometer (DCP) tests.
- Service clearance of all locations.
- Installation of standpipe piezometers and standpipes and subsequent monitoring/sampling visits. – (contamination assessment from installation monitoring: Measurements of VOC’s using a Photo Ionisation Detector; Thickness of non-aqueous phase liquid layers within groundwater using oil/water interface meter; Measure concentrations of landfill gases, temperature, gas flow rates and pressure.)
- Surveying of exploratory hole locations.
- Geotechnical testing.
- Chemical testing.
- Provision of a factual report.
Challenges
Clean drilling techniques had to be applied to each borehole to prevent the downward migration of any contamination as the borehole was progressed. Concept used reducing diameters casing strings and tooling with environmental seals to ensure aquifer protection.
All ground investigation work types including rotary open holing and percussive drilling, trial pitting, rotary coring, CPT Testing, GPR surveying, in situ testing were carried out in a combination of night and day works under various levels of traffic management.
All operations had to be co-ordinated and planned in conjunction with the MAC Motorway Area Contractor BBMMJV and their appointed supply chain for delivery of traffic management so as not to disrupt the highway traffic flow, inconvenience the road users in any way and also work with and alongside other sub-contractors and 3rd Parties.
Outcome
All of the work was completed to the satisfaction of the BBMMJV, to programme and within project specific budget, on time and without commercial conflict.
Concept provided all data in digital format for scheduling, carrying out laboratory testing and analysis and presenting all final data/results and summary in a Factual Report in accordance with BBMMJV programme requirements for each individual project.