Category Archives: Site Investigation

Site Investigation – Trowbridge, Wiltshire

Southwest Environmental has recently undertaken a site investigation in Trowbridge, Wiltshire. The purpose of the investigations were two fold.

  1. Find Out Soil Strengths
  2. Expose Existing Footings
The work was undertaken over 2 days, and the data was used to write a report on the state of the ground on site. The existing pad footing appear to be bedding directly on to the bedrock which was a cornbrash limestone: Limestone, medium- to fine-grained, predominantly bioclastic wackestone and packstone with sporadic peloids; generally and characteristically intensely bioturbated and consequently poorly bedded, although better bedded, commonly somewhat arenaceous units occur in places, particularly in the upper part. Generally bluish grey when fresh, but weathers to olive or yellowish brown. Thin argillaceous partings or interbeds of calcareous mudstone may occur.
SPT data was used to provide input data for bearing capacity calculations. These are then provided to the structural engineer.
SWEL undertake site investigation all over the UK. We try to do things on a quick turnaround where possible. 

Site Investigation & Phase 2 Assessment – Islington, London. N19

Site Investigation & Phase 2 Assessment – Islington, London. N19

Acting on instructions from a corporate client Southwest Environmental Limited have carried out an Environmental Site Investigation in connection with a property acquisition / purchase. 
SWEL managed to deliver a reduced scope report, sufficient for our client’s needs within a 3 week period, despite having trouble on site with buried services. 
The scope included the collection of 20 soils samples, with breaking out at each position. There were 3 deeper holes drilled, for installation of boreholes for gas and ground water monitoring. Although this was not carried out owing to time frame. 
Statistical Analysis of Results 
The site was operational at the time of the investigation, with high level of vehicular and pedestrian traffic,  despite this SWEL managed to complete site works within 2 days.
Soil testing was conducted on a rapid turnaround, and results were published as part of a contamination assessment (Phase 2). The site was found to have elevated levels Benzo-a-Pyrene, are carcinogen and as such will require remediation. 

Site Investigation – Bristol

Site Investigation – Bristol

Recently Southwest Environmental Limited submitted a  Desktop Study for a site in Bristol, to Bristol City Council for scrutiny. Despite SWEL recommending that the site was fit for use, with no further work recommended BCC were of the opinion, that some further investigations were required. 
BCC were very pragmatic in the scope of these further investigations, and limited the scope to a number of hand dug trial pits, which were then used to ascertain the extent of made ground on site.
The finding were that despite having some made ground in the form of crushed brick under the driveway, the ground under the proposed structure was natural ground.

Brick Footings

Made Ground . . . of Brick

Ordinarily it would be standard practice to take samples and analyse them for a suite of chemicals as part of a Site Investigation . However, in this instance the checks for the presence of made ground, combined with floor slab sub-ventilation were deemed as an appropriate mitigatory measure.

This saved around ¬£5000 in costs, which on a small project would represent a significant percentage of  the overall project value.

Geotechnical Investigation Belluton near Bristol

Geotechnical Investigation Belluton near Bristol 

In support of some road stabilisation work SWEL have carried out a geotechnical investigation at Belluton near Bristol.

Despite tight access, drilling works started in a timely fashion, with recovered of some excellent core samples. Holes were advanced to a depth of 15 meters, with dynamic sampling in soils and weathered rocks, and coring in rock proper.

Dynamic Samples from Ground Level in c. 3 Meters Depth

Core Samples from Weathered Rock Head

Close Up of  Core Fragment

SPT results and disturbed samples from Soils. 

The investigation is to provide data for a cutting for road widening. The rock seems very competent, but soil nails are proposed for further strengthening. Samples were tested for aggressive ground characteristics, and a variety of classification and strength tests.

Geotechnical Investigation Bristol

Site Investigation Bristol

Site Investigation Bristol

Acting on instruction from a property owner in Bristol. Southwest Environmental Limited are currently undertaking a Geo-environmental site investigation in Bristol.

The site is an dis-used petrol filling station, there are concrete filled tanks on site, and various buildings with above ground tanks and assicoated storage.

Site Investigation Bristol – Buried Services and Pipework were Present

Site Investigation Bristol – Site Works were completed in One Day

The site works were undertaken in December 2015, with reporting no being progressed.

A full report will be prepared to collate finding of investigation and to compare soil quality against various guide values. 

Site Investigation Bristol

Contaminated Land Site Investigation – Epsom and Ewell

Southwest Environmental have recent been commissioned to undertake a contaminated land  site investigation within the London borough of Epsom and Ewell. The site investigation was commissioned on Wednesday the 30th April, and work began on the 6th of May. Making for a very prompt start.

I addition to the soil sampling of a car park area, vapour monitoring was also undertaken in the existing building which is ear marked for conversion under the new permitted development rights.

Another riveting photo!

The samples are currently with the labs on a very quick 3 day turnaround meaning the draft (soils only) report will be issued just two weeks after commissioning.

Geotechnical Investigation Bristol

Geotechnical Investigation Bristol

SWEL were engaed to undertake a geotechnical investigation within an existing reatial unit, structural engineers required ground data so as to construct a mezzanine floor.

There was restrict access on site but with the help of an expert crew from Stunt Drilling Services,  3 rotary boreholes were advanced 10 meters below ground level in to the Sandstones and Coal measures that underlie the site.

Core recovery improved with depth, and rock core logging was used to give empirical rock mass strength estimates.

Below is a video of site works (drilling rig) underway.

Running a drilling rig in a building can cause a build up of fumes and as such an extractor system was used to suck exhaust gas outside the building via lots of ducting.

Site Investigation Bristol

Geotechncial Consultants Bristol

Site Contamination Asessment Bristol

Site Contamination Assessment Bristol – Introduction

Acting on instruction from a planning consultant, Southwest Environmental have undertaken a site contamination assessment in St. Philips, Bristol.

The site is currently in use as a builders yard and is ear marked for development.

Site Contamination Assessment Bristol – Work Undertaken

Six exploratory location were chosen and soil samples were taken from the top meter of soil, there was a great thickness of made ground on site, in places extending to the full depth of the exploratory holes.

Bristol has many buried river channels and it became apparent that a buried river channel or culvert runs along the site boundary.

breaking out positions

There was a considerable thickness of concrete on site, and made ground was hard going composed for the most part of brick, whether whole or in parts.

Geologically Bristol centre is normally river silts over marls.

Sample were sent for testing and results are awaited.

Site Contamination Assessment