In this Issue:
The Warewithal : Review of summer work, sun cream and summer parties
Focus: Leicester Square
Case Study : Remedial Verification in East Hants
Geotechnical Investigation : An In-Tree-Ging Site
Staff News : Rebecca, our Falklands representative
Whilst the UK has had one of the hottest summers on record, all of us at WDE have been enjoying a very busy period. Sun protection and sun hats have been an essential piece of site equipment, with red faces where they have not been used.
Not a cloud in the sky in Southampton ..
Areas of work have been varied with geo-environmental assessments completed as well as the validation of remedial works. We have also seen an increased demand for geotechnical assessments on sites for foundation and drainage purposes.
WDE were shortlisted for one of their projects at the Ground Engineering Awards (Best Geo-Environmental Project) and enjoyed the night, even though we did not win. We have also submitted one of our projects for consideration at the Brownfield Briefing awards which are to be held towards the end of September, hopefully we will be more successful this time.
We also enjoyed an end of summer party for all staff with some fine dining (and a few too many G&Ts).
An In-Tree-Ging Site
A site in Harpenden had experienced historical subsidence and this was thought to be caused by dissolution features within the chalk. A geotechnical investigation was carried out and showed that the chalk was in fact of medium density with no soft spots and was overlain by a layer of highly plastic clay. However a number of very tall mature trees in very close proximity to the building were found to be causing ground heave due to the highly shrinkable clay. This highlights how important a good geotechnical investigation is for design of foundations.
|Remedial Verification - East Hants
This summer WDE were involved with the remedial verification of a former industrial site in Hampshire prior to its redevelopment for residential land use. Unusually, WDE were not involved in any previous intrusive investigation work and were relying on somewhat unreliable reports. While the lack of exact knowledge on the site meant we never knew what we might find in each excavator bucket, one thing was definitely clear – there was significant hydrocarbon impact.
As a former Victorian brickworks and later a builders merchants and vehicle servicing yard, the site had suffered from significant hydrocarbon contamination, focused around the numerous underground footings and structures associated with these previous land uses.
Importantly, throughout the excavation, we also had to ensure that we did not expose the chalk aquifer below the site, which was at ~6m bgl but had a confining clay layer above. The site was situated within a SPZ 1 for Portsmouth’s water supply borehole. Due to its sensitivity, the regulatory authorities were all keeping a watchful eye on progress, with WDE providing regular updates and holding site meetings during the remedial works.
The remedial methods used on site were relatively straightforward in theory; hydrocarbon impacted material within the upper 3m was excavated and placed in several windrows for onsite treatment. With regular turning of the biopiles, this summer’s long heat wave helped to remediate the material rapidly and they were later used to backfill the excavations under the CL:AIRE CoP. The heat wave was also beneficial for those of us working on our tans! As the site work here draws to a close and the weather gets cooler, it is now time to return to our warm office and catch up on all the paperwork and report writing.
WDE were requested to undertake a site investigation inside a commercial unit in Leicester Square, London prior to internal alterations and their potential effects on party walls with adjoining properties. There were a number of physical constraints which needed to be factored into the design of the investigation which included an underground basement, underground services, traffic for dropping off equipment, height restrictions and weight restrictions for the ground level floor.
Steel sheets and supports were used on the ground level flooring to enable a tracked window sampler rig to be utilised to determine the ground conditions to 17m bgl. In the basement a number of foundation pits were excavated along with conducting dynamic probes using electrical power to negate issues with exhaust fumes in confined spaces.
Latest graduate recruit Rebecca Arthur-Almond (originally from the Falkland Islands) comments on her first few months at WDE..... "I started working for WDE in May, so have managed to enjoy good weather for all my onsite learning so far. However, the thought of colder weather doesn’t put me off entirely as I am thoroughly enjoying having an interesting job that involves both office and field work, and is actually related to my degree. WDE is a small company which is friendly and variable – not just a faceless corporation – so I am feeling lucky to have found it; I have the opportunity to work with a good team and learn some new skills as well".