Our Terrier drill rig, Tinky, recently celebrated its sixteenth birthday. In that time it has had 2 new head gaskets, 15 calibrations, 22 oil changes and services, 2 new tyres, 2 new tracks, 1 rebuilt mast frame, 1 new radiator , 1 new weight guard and a new fan. We know that good maintenance is the key to keeping any machine working and we like to think we’ve done our Terrier proud. It has certainly paid us back.
It may be sixteen years old but last week it still managed to dynamically sample 25m of weathered sandstone to 5m depth with SPT tests every metre plus completing an additional four dynamic probes to competent bedrock at 9.5m and installing four gas monitoring wells to 1.5m. All this in two days including a round trip mobilidsation of over 300 miles. Hats off to Tinky.
We are looking for dynamic sampling operatives. If you think you fit the bill then give Angus Gale a call on 01296 739400 or email your CV to Angus Gale.
The sewage system in the UK is under increasing demands from the increase in rainfall volume and intensity associated with global warming and from the demand of new housing developments.
These pressures required a change in policy approach to a more sustainable system. On 6th April 2015 the government introduced a new planning policy aiming to lessen the likelihood and impact of surface water flooding from new developments of 10 dwellings or more; or equivalent non-residential or mixed development, by encouraging the use of sustainable drainage systems (SUDS).
Soakaways and permeable paving are two types of SUDS which are used to limit the impact of surface water discharge from new building developments. Designing these systems requires careful measurement of soil permeability. We offer a comprehensive range of testing methods compliant with NHBC (Chapter 5.3) and BRE (Document 365) guidance.
For further information please contact Steve Partridge – 01296 739413
Let’s face it, sometimes you just need CBR results fast. Really fast. Maybe you need to identify any soft spots in a piling mat or in a road sub-base before the compaction plant leaves site. Or – be honest – maybe you just forgot to get the required testing done in time. Either way, we have a solution for you. We can test your sub-base using our Clegg Impact Hammer, typically completing 80+ tests in a day with results available immediately. Although the CBR value measurements aren’t as accurate as those obtained from a conventional test, we reckon they are acceptable for about 90% of the enquiries we receive.
For further information please contact Steven Partridge – 01296 739413
Well, in our case the answer is very safe indeed. We’ve just completed our annual HSE audit, carried out by an independent auditor on our clients’ behalf, and scored a record 93%.
The auditors praised PrismERP, the IT system we have developed over the last decade for both managing HSE and integrating it into every aspect of our operations. With further upgrades to PrismERP planned for the coming year, we are determined to get an even higher score next time round.
PrismERP is commercially available. If you’d like to know more about how it might help your organisation please contact Duncan Eastland.
Another post discussing the joys of working at a busy airport. This time we were asked to advise on the allowable bearing capacity for a foundation to be installed at 2m depth, without either excavating a trial pit of drilling a borehole.
We opted to carry out a series of dynamic probes, using our lightweight terrier drill rig, along the line of excavation, using the data to calculate an equivalent SPT ‘N’value and thence an allowable bearing capacity. We were able to provide our client with results in real time, ensuuring there were no delays to the construction programme.
Working ‘airside’ at Heathrow Airport is always a challenge, but when our client contacted us requesting plate bearing testing of the ground prior to them lifting a new chiller refrigeration unit using a mobile crane at Terminal Four we were happy to help.
The only kind of chilling our engineer enjoyed was the cool breeze while he worked through the night to ensure our testing was completed safely, on time and on budget, allowing the aircraft stand to open in time for the first plane arrival.
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
The pressure to building new housing seems to be constantly in the news these days. Developers working to meet this demand are increasingly finding that they are required to find sustainable methods for disposing of the rainwater from roofs and paved areas. The days when this could just be discharged to the municipal sewer are long gone. Instead, wherever possible, the water must be disposed of into the ground via soakaways or other similar ‘infiltration features’.
Designing these requires careful measurement of soil permeability. We offer a comprehensive range of testing methods, from hand-dug percolation tests for Sustainable Drainage Systems (SUDS – NHBC Chapter 5.3) to machine-dug test pits for full scale soakaway tests (BRE 365). If site access is limited we can even carry out the requisite testing in boreholes drilled as part of our geotechnical/environmental investigation of the site.
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.
A prominent pipeline client came to us with a problem. A ‘positive’ problem that is. A section of their pipeline runs underground next to a railway line. The railway’s overhead high voltage power lines were causing an amplified positive electrode potential in the ground, which in turn was leading to increased corrosion of their pipeline. In these cases, cathodic protection is the usual solution.
A typical cathodic protection system would comprise a series of shallow earthing rods installed at regular intervals along the pipeline. However, this requires access for maintenance in the future to the entire pipeline. But these pipelines run for hundreds of miles through agricultural land, some of which is only accessible during certain periods of the year. The solution was to design a single anode string capable of achieving the required negative electrode potential in a vertical design. Thus saving on space, maintenance and cost
The client’s senior cathodic protection engineer approached us to see if we could drill a 75m deep borehole and undertake the (negative) anode installation. We took the challenge and set about devising a safe method for installing a multi core anode string weighing more than 300kg! The borehole was installed through 18m of gravel into underlying mudstone. Just to complicate matters further, our environmental appraisal identified a potential risk of penetrating into a sandstone aquifer beneath the mudstone. To mitigate these risks and achieve the required potential we had to install a vent pipe to the base of the borehole, a tonne of coke, gravel and a bentonite seal at the top of the mudstone to ensure the underlying aquifer was protected.
Exactly how we did all this is our secret but needless to say it involved a large rig, and unusually for us, a lot of “negativity” ………….But happy pipeline equals happy client – now that’s positive.
