Geo-Environmental Services
We were contacted by one of our regular clients with an urgent request to carry out pile probing at one of their sites in London. We were able to be on site the next day, using our Geoprobe rig to clear 55 pile locations to a depth of 4m, all before 3pm. To make matters even better, the sun shone all day.
For more information about our pile probing service please contact Duncan Eastland – 01296 739431
Contract Value: <£2k
Drilling has tradionally been pretty poorly regulated. Light cable percussion rigs (more commonly known as shell and auger rigs) still dominate the UK drilling market. They are crude, simple to operate and provide low quality samples but they live on because they are relatively cheap.
One reason they are cheap is that their operators are unqualified. Drilling has been seen as a job not a career. But lack of proper training has led to a woeful safety record; it is rare to see a 40-something shell and auger driller who still has all his fingers intact.
The British Drilling Association (BDA) has been working hard for some time now to encourage clients and consultants to require drillers working for them to hold a professional qualification – in this case an NVQ in Land Drilling. All our drillers hold this qualification. Our latest trainee, Alex, completed his NVQ this week.
If you’d like to know that your drilling requirement is going to be fulfilled safely and professionally then we’d be love to talk to you. Please contact Angus Gale (Tel: 07748 358304) for more information.
The answer is when it’s not calibrated.
The Standard Penetration Test, or SPT, has been the mainstay of geotechnical site investigations in the UK for decades. The test is simple, quick and cheap and it’s particularly suited to the light cable percussion drill rigs that are so widely used in the UK.
What isn’t generally appreciated is that even a low tech test such as this requires proper calibration in order to yield consistent, reliable results. In fact Eurocode 7 requires the SPT hammer to be calibrated annually. Unfortunately very few drilling contractors bother to do this and, in our experience, few consultants know that they should be asking for it. Given that results from out of spec hammers can vary by as much as 50%, we think this is something that should be given more attention.
We’ve put our money where our mouth is and now all our SPT hammers are correctly calibrated and all our drill rigs come with up to date LEAA inspection certificates. If you’d like to know more about our drilling capabilities please contact Angus Gale – 01296 739433.
We are accustomed to working for the big hitters of modern industry. However, today we were handed the opportunity of working around one of the big hitters from history. This WWII machine gun bunker holds listed status, and rightly so. It’s one of 18,000 built, around the coastal areas of the UK during Churchill’s defence against Operation Sea Lion.
Our plucky little rig was able to negotiate perimeter fencing, dense undergrowth, steep inclines, tank traps and machine gun bunkers just to get on site. It all sounds more “Band of Brothers” than “geotechnical site investigation”. In all 28m of dynamic windowless sampling with SPTs (and 2″installs) plus 80m of dynamic probing were effortless completed.
Now that’s the spirit…………..
……is our mini dynamic sampling rig! In fact, its photographed here having its oil checked during a day’s work at a site on the south coast.
The geotechnical survey, which comprised standard penetrations tests (SPTs), dynamic probing, CBR tests and plate bearing tests, was designed to allow the design of foundations for a leading supermarket chain’s new store.
The site had a history of industrial development so, not surprisingly, it was littered with large, buried concrete obstructions from previous structures (foundations, beams and piles). We will soon be returning to complete pile probing at each of the new pile locations to enable the augers of the piling machines to keep turning thus avoiding expensive standing time.
Hopefully it will have stopped raining by then…..and no, sadly, we didn’t find the pot of gold at the end of the rainbow.
No-one can say that our workload isn’t varied. Last week one of our drilling crews completed the following schedule:
Monday – Geotechnical investigation including U100 sampling and SPT testing with our Terrier drill rig;
Tuesday – Water well installation using rotary rock roller with our Commachio 205;
Wednesday – Environmental investigation at a filling station using hollow stem augering, again with our Comacchio 205, while a new canopy was being installed;
Thursday and Friday – Deep water well installation using down the hole hammer to penetrate into a limestone aquifer.
We love a bit of variety in life and this week has proved it so. Time for a rest…….next week looks busy………
Actually, there is nothing mythical about Subadra being commissioned to install shallow monitoring wells at the Daedalus Airfield Development! We constructed several shallow wells over the course of two days using our Hollow Stem Auger drilling system.
Lee-on-Solent is known for its sand and a dense gravels which are more or less guaranteed to make drilling difficult. So to avoid this we used our powerful Comacchio drilling rig which ensure we reached the target depth at all the drilling locations with minimal disruption to the site. We then installed 50mm diameter wells to allow future groundwater sampling. All our materials were sourced locally to enable us to take the minimum of equipment and vehicles thus reducing our carbon footprint for the works.
We even had time to the collect soil samples for the Principal Contractor and get them
analysed for WAC by our in house lab facility. As a result of our prompt and efficient service the client retained us to carry out a more detailed geotechnical investigation at the site. No myth there then!
The combination of restricted head room and a ‘confined space’ presents major obstacles to any site investigation. However, our Terrier rig was able to gain access and complete a geo-environmental investigation in such a space. Its quite amazing where this little rig can get.
Access was through a standard doorway working with an overhead ceiling clearance of
less than 30mm with the machine set up. Precision operation was required to ensure we completed five boreholes, each to 6 metres in depth, with SPTs every metre, all in a safe and efficient manner.
The nature of the confined space meant that exhaust gases from the Terrier’s engine had to be vented to an outside area. We used an extendable sectional exhaust pipe to ensure a safe working environment. But just in case we also carried out carbon monoxide monitoring to ensure our crew’s safety.
Even better, our work was completed without the need to close the car repair workshop we were working in. allowing our client to continue panel bashing, filling and spraying to his hearts content.
Have you ever wondered what is below your feet when you’re filling up at a petrol station? Big old tanks, that’s what! We’ve investigated the ground at more filling stations in the UK than anyone else and so, not surprisingly, we have a have a pretty detailed understanding of how they are put together. This sort of experience is invaluable when
it comes to assessing potential environmental risk – we know how and where problems
can occur…
Obviously owning our own specialist drilling systems, UKAS and MCerts accedited
laboratory and remediation equipment also has benefits, both in terms of cost and speed of turnaround.
For pragmatic advice and cost effective assessment strategies for the assessment
of filling station sites please contact James Skinner on 07770 611554.
We were commissioned to carry out a geotechnical investigation, including rock coring, at a site located just a stone’s throw from the busy harbour of Dover.
Our Commachio 205 and drilling crew were able to produce high quality cores and gain SPT/CPT data from 4 boreholes, each drilled to a depth of 20m below ground level. All completed on time and on budget.
Voids were encountered at various depths fueling rumours of secret smuggling tunnels similar to those we found in Margate last year. Unfortunately the only treasure recovered were metres and metres of chalk. Better luck next time lads!