Deep Soil Mixing solution used on HS2 in the West Midlands

It is fantastic to be part of the largest infrastructure project in the UK and it was exciting to get involved in HS2, to see the environmental ambitions and standards on site and play our part in contributing to these. Deep Soil Mixing were working for Land and Marine Engineering Ltd (LME) who were contracted to HS2’s enabling works contractor LM JV (Laing O’Rourke and J. Murphy & Sons).

Take a look at what HS2 has said about our work on the project here

Before and after aerial shots of the site

Deep Soil Mixing Ltd Hires New Civil Engineer Apprentice

Ground remediation specialists Deep Soil Mixing Ltd has taken on a new apprentice at its Bedfordshire headquarters.

Brandon Wilson has been appointed as a Civil Engineer Apprentice at the award-winning soil mixing firm and will combine study with on-the-job training in his new role.

Deep Soil Mixing Ltd’s Managing Director Robert McGall says: “We are all delighted with the appointment of Brandon as an apprentice with us – especially as he joins at such an exciting time in the company’s history when we are involved with a vast range of soil stabilisation projects across the UK and Ireland.

“As well as working in all departments of Deep Soil Mixing during his apprenticeship, Brandon will be affiliated to Anglia Ruskin University and the Institute of Civil Engineers (ICE) where he will study for his BSc (Hons) Civil Engineering with Project Management degree.

“In terms of the work he’ll do as an apprentice, he’ll be a firm member of our team – from working onsite to see how the soil mixing process happens through to helping in the testing procedure.

“With a background as Trainee Civil Engineer for Kier Infrastructure before recently joining us, Brandon has experience of working on ground engineering projects and we have no doubt he’ll be an invaluable member of our team throughout his apprenticeship – and, we hope, far beyond.”

As the demand for soil mixing has grown over the years, so has the company which now has several offices across the UK, including in Staffordshire and Northern Ireland.

“I am pleased that Deep Soil Mixing has taken me on as an apprentice,” comments Brandon Wilson.

“This is a fantastic opportunity not only to study civil engineering but to gain first-hand knowledge and understanding of deep soil mixing technologies.

“With its ability to both speed up project times and cut the carbon footprint of projects in the construction industry, I’m excited to learn all there is to know about deep soil mixing solutions as I believe it is important that all construction projects now look to environmental solutions like soil mixing..”

Robert McGall adds: “Soil mixing techniques are likely to become standard practice over the next few years with more and more emphasis on construction cutting its carbon footprint. In 2021 we should be turning away from excavate and cart away if possible and remediate soil in-situ. Therefore, we’re investing in people – we want to develop the company and Brandon’s appointment is a big part of our planned expansion.

“We’re keen to bring onboard the next generation of civil engineers who want to specialise in ground stabilisation and deep soil mixing projects across the UK and around the world.

“Brandon has made a great start in his role as Civil Engineer Apprentice to-date and we look forward to working with him as he continues to achieve practical and theoretical knowledge throughout his apprenticeship.

“After the challenging year everyone has had, we’re looking forward to a much brighter 2021 and to working on further innovative construction projects where we have the opportunity to apply deep soil mixing solutions.”

Deep Soil Mixing Ltd Launch Environmental R&D Project

Ground remediation specialist Deep Soil Mixing Ltd has this month launched a research and development project to explore new environmentally friendly binders from recycled material for their soil mixing process.

Many companies have in the past used cement as their main binder for soil stabilisation but Deep Soil Mixing Ltd are currently working to utilise new recycled binder solutions to make the soil mixing process even more sustainable than it is already.

Developers, public bodies, contractors, and investors are recognising that environmentally friendly, sustainable construction provides not only long-term positive environmental benefits but also immediate financial payoffs as well. Furthermore with the UK government calling for a reduction in construction excavated material being sent to landfill together with the increase in landfill charges, improvement of existing ground is now high on the sustainable construction agenda, helping to reduce the industry’s carbon footprint when it comes to developing sites.

Deep Soil Mixing Ltd MD Robert McGall says: “We have to be innovative in the way we build to tackle carbon emissions and this means starting with the groundworks. UK soil contains about 10 billion tonnes of carbon, roughly equal to 80 years of annual greenhouse gas emissions so it is vital that we don’t where possible dig this out and take to landfill. Time and time again we see proposals where contractors are looking to remove poor soil such as peat from developments and this needs to be reviewed when there are solutions such as soil stabilisation which treats peats in-situ changing its geotechnical properties without the need to remove it.

“Soil mixing is by nature of what we do environmentally friendly. By making use of the existing ground on site and improving it to achieve a specified bearing capacity and shear strength, there is no need to excavate, cart away or dispose of the existing material off site and then bring in costly and bulky fill materials. It is not just about improving unsuitable ground but aims to turn poor quality soils and fill into acceptable bearing strata for numerous applications.

“This in turn reduces the carbon footprint on a site with less vehicle movements and you are not moving contaminated or poor-quality ground to landfill. On one site alone following a carbon footprint calculation using soil mixing we reduced the carbon emissions by just over 70% as opposed to excavate and cart away and fill.

“Over the coming year we will be undertaking R&D at our research facilities in Bedfordshire and Staffordshire including extensive laboratory treatability studies in which a wide range of novel environmentally friendly binders and additives will be tested together with a range of soils and contaminants. In parallel, extensive field trials will then follow. Extensive in-situ testing, sampling and groundwater monitoring will then be carried out together with extensive laboratory testing of the site samples and assessment of the field measurements.”

Deep Soil Mixing is no stranger to ground breaking R&D as the company was at the forefront of soil mixing in the UK in 2009 as part of the Government funded Soil Mixed Remediation Technology (SMiRT) initiative with the geotechnical department of Cambridge University. The company has also been leading the way in improving the plant and equipment used for soil mixing and in 2008 they designed and developed a new double-rotary mixing attachment. The double rotary mixing attachment has proved a great success compared to the industry standard single rotary mixing head as the double rotary forms more consistent homogeneous soil mixed columns, enabling geotechnical engineers to have confidence that the system provides consistent results.

“We are hoping to publish our results in the summer of 2021 and highlight further the importance of sustainability to the construction industry from the ground up. In 2020 we should not be removing soil to landfill and effectively moving the problem elsewhere when there is a geotechnical and sustainable solution available. Soil mixing has been widely used across the USA, Europe, Australia and the Far East and the UK should now use it more. If we are to build three million homes to solve the housing crisis, we should be using more brownfield land and in doing so we should not be removing soil from site.

As a ground remediation solution soil mixing reduces project times, costs and the carbon footprint on construction projects compared to other more traditional ground engineering methods such as various types of piling, excavate and cart away, dynamic compaction, surcharge etc.” adds Robert.

Deep Soil Mixing Ground Engineering Specialist of the Year at Construction News Awards

Deep Soil Mixing Ltd has won the Ground Engineering Specialist of the Year at the 2019 Construction News Specialists Awards.

The inspirational winners of the 2019 Construction News Specialists Awards were crowned in front of the industry on 27 March at the Grosvenor House Hotel, London.

The Construction News Specialists Awards brought together over 750 of the UK’s leading specialist contractors for a glittering evening of celebration, recognition and networking.

After a face to face review by a panel of over 70 expert judges and facing competition from companies such as Lankelma, Groundforce, Keltbray Piling, McCoy Contractors and Volker Ground Engineering, Deep Soil Mixing Ltd won the award.

The judges said: “Deep Soil Mixing – despite some major competition in this category – stood out for its ability to organise and manage business growth, as well as the healthy approach it has taken regarding the promotion of workforce diversity.

“The company ticked all of the requisite boxes for the category and not only met the judges’ criteria, but exceeded them.

“From the completion of a challenging asbestos-contaminated slope-stabilisation job at Mytholmroyd, to undertaking a first-time soil-mixing scheme for housing foundations in St Mary’s Bay, Kent, it has been a year of firsts for Deep Soil Mixing.

“Despite its size Deep Soil Mixing Ltd has met the challenge of organising its own diversity, managing its business in different ways to some of the bigger firms it was up against. Its success has been formed around innovation and safety, ticking all the boxes around sustainability.”

CN editor Tom Fitzpatrick said: “The Construction News Specialists Awards recognise the achievements and the outstanding contribution of those companies who bring the innovation, the workforce and the vision to help this industry realise its potential.

“Congratulations to all our worthy winners whose work continues to buck the Brexit doom and gloom and showcase the best of the UK construction industry.”

Deep Soil Mixing Ltd Director Colin Critchlow said: “Awards are a great way for us as a business to reflect on our successes of the last year and we have to thank all our staff and partners who have all played a part in winning this award. In particular our long-term Geotechnical Designers, Byrne Looby, who provide detailed designs for our soil mixing projects.

“Byrne Looby has had a major influence in helping Deep Soil Mixing Ltd to develop soil mixing. They have successfully designed and overseen the implementation of soil mixing technology to re-engineer the soil at previously unusable sites, such as flood plains with deep soft compressible soils, to provide improved bearing and minimise settlements for a range of projects for Deep Soil Mixing Ltd.

“Being shortlisted and then selected as the winner from the hundreds of entrants in the prestigious CN Specialist Awards is a fantastic achievement and distinguishes Deep Soil Mixing Ltd from our competitors.”

Deep Soil Mixing has been shortlisted for two Ground Engineering Awards

Following hot on the heals of the Construction News Awards Deep Soil Mixing Ltd has now been shortlisted in two categories for the Ground Engineering Awards 2019. The two categories we have been shortlisted in are:

  • Brownfield Redevelopment Project of the Year
  • UK Project with a Geotechnical Value of up to £1M

The Ground Engineering Awards are prestigious awards and we are honoured to be short listed amongst a number of other successful contractors and consultants. Winners will be announced on the 5th of June in London.

Deep Soil Mixing Shortlisted for two Construction News Specialists Awards

We are pleased to announce that we have been shortlisted for two Construction News Specialists Awards in the categories Ground Engineering Specialist of the Year and Project of the Year by a Specialist Contractor (subcontract up to £1m). The Project of the Year was for our Scout Road Slope Stabilisation project

The recognition of being shortlisted acknowledges the hard work and dedication made by our employees and partners over the past year.

The Construction News Specialists Awards, now in their 15th year, recognise the outstanding achievements of specialist contractors, and is the only national awards to do so.

Construction News Editor Tom Fitzpatrick said: ‘Specialists are continuing to up their game in difficult economic circumstances. Our expert judges have now shortlisted the companies who represent the best of the people, initiatives and projects in the construction industry supply chain’.

Deep Soil Mixing Director Colin Critchlow comments: “We are delighted to have been shortlisted for two awards highlighting our work in 2018. The year saw some great advances in Deep Soil Mixing Ltd’s position within the industry, with the completion of the Scout Road project and the use of soil mixing on a housing project in Kent, together with soil stabilisation work at Dover Harbour to name but a few. We are facing impressive competition but we are hopeful in receiving official recognition for what has been a brilliant year.”

The awards evening is on 27 March 2019

Soil Mixing Technology Double Rotary Auger Brings Improved Geotechnical And Engineering Qualities Than Single Rotary

When considering soil mixing for a ground remediation project it is important to consider the equipment being used, in particular to look at the benefits of using a double rotary auger as opposed to the more commonly used single rotary auger.

Soil stabilisation contractor, Deep Soil Mixing Ltd’s Director Robert McGall developed a double rotary mixing head in 2010 and has since then continued to develop the mixing head design and techniques to further improve what is already a very successful system.

The design improvements made by Deep Soil Mixing Ltd to various double rotary mixing heads, follows from R&D work and in situ trials undertaken by Deep Soil Mixing Ltd’s Directors Robert McGall and Colin Critchlow for the Government sponsored soil mixed trials ( SMiRT ) in 2010 alongside Cambridge University.

These trials proved that single rotary mixing was not as successful as the double or multi rotational mixing heads which are used on all Deep Soil Mixing Ltd projects.

Deep Soil Mixing Ltd’s bespoke double rotary auger system has twin paddles and these move in opposite directions to enhance the process of soil mixing with the distribution of the binder vastly improved and mix designs are more finely tuned and accurate in the soil mixing process. This in turn improves many of the geotechnical and engineering qualities of the mixed soils, more so than single auger mixing heads. This in turn brings economic benefits to the client.

From their R&D facility in Staffordshire Deep Soil Mixing Ltd have been working on the next generation of mixing heads and are now trialling these on site. The results from Deep Soil Mixing’s laboratory show the results are again proving that double or multi rotational mixing is far superior to single rotary action.

Innovation in soil stabilisation through use of Cutter Soil Mixer

We saw a question on LinkedIn recently asking to what extent the Cutter Soil Mixer had been used in the UK and if soil mixing and the cutter soil mixer for retaining walls was a viable option for the UK.  We thought we would answer that question and highlight how innovation in engineering can deliver solutions that are both cost effective and environmentally friendly as well as saving time on construction projects.

Deep Soil Mixing Ltd has used the Cutter Soil Mixer four times in the UK now over the last six years including the Mersey Gateway Bridge, Cheshire in 2016 where, after undertaking extensive soil mixing trials on behalf of Merseylink CCJV, we installed over 1800 panels at a number of locations across the north landside area of the Mersey Gateway project and these panels were designed to stabilise the ground in areas around the various bridge structures so that further construction work could be undertaken. Visit our case study page for more information 

We also used the Cutter Soil Mixer on a retail park in Runcorn, where we installed soil mixed panels across the site as well as a soil mixed mattress and soil mixed wall next to a Major Accident Hazard Pipeline (MAHP), to lock in chemicals and prevent leachate to ensure the ground was stabilised for the building works to commence. During this project we installed a secant retaining wall which satisfied two functions (1) to retain a canal embankment and (2) assist in creating a plume stop for ground contaminants.

More information on the Runcorn retail park project can be found here.

We are currently using the cutter soil mixer on a housing project in Kent and have also recently used the Cutter Soil Mixer on a project at Dover Harbour.

Deep Soil Mixing Ltd has undertaken a wide variety of projects and have practical experience in the design and construction in a wide variety of soil mixed solutions from road construction through to dealing with contaminated and poor-quality ground, flood alleviation and slope stabilisation. We installed circular secant cells on the banks of the River Clyde for the Commonwealth Games Village project to stabilise and retain the embankment from further movement and also on the Manchester Ship Canal where rotational slippage was occurring..

We have used secant soil mixed columns as a sub-foundation on numerous projects.

We are becoming renowned for successfully undertaking challenging and difficult projects that others may not wish to do and can demonstrate the impact this is making in the world of civil engineering and illustrate how soil mixing techniques can transform severely contaminated or poor-quality land into commercially viable land that can be developed.

Our method of soil mixing remediates the soils in-situ. Using various binders for various applications we carry out soil mixing of the existing site soils to either produce large diameter stabilised columns, mass mixing for full depth treatment, mass mixing over the top of the columns to provide a transfer mattress, trench mixing to provide cut-off walls or even PRB walls, we do not remove materials from site, this has significant advantages of reducing CO2 emissions, improves sustainability and is recycling on a grand scale.

Soil mixing also reduces project times and costs as well as your carbon footprint on construction projects compared to other more traditional ground engineering methods such as various types of piling, excavate and cart away, dynamic compaction, surcharge etc. You are treating the ground in-situ and will not incur costly landfill charges.

If you have a project that has land that is contaminated or contains peat or if you want to improve the strength of weak soil and do not want to dig and cart away the ground please get in touch with us.

Deep Soil Mixing Helps to Win Awards

Two projects that Deep Soil Mixing Ltd provided the soil stabilisation solutions for have just won awards – Mersey Gateway and Earnsdale Reservoir.

In the ICE NW awards The Mersey Gateway won the ICE 200 special award – Deep Soil Mixing initially undertook soil stabilisation trials for the joint venture team and were then awarded the multi million pound project to install over 1800 soil mixed panels at a number of locations across the north landside area of the Mersey Gateway project.  These panels were designed to stabilise the ground in areas around the various bridge structures so that further construction work could be undertaken. More information about the Mersey Gateway project can be found in our case studies.

Another project that Deep Soil Mixing Ltd carried out soil mixing for won the ICE North West Small Projects award – Earnsdale Impounding Reservoir Improvements.

Earnsdale Impounding Reservoirs is situated 1.5km to the west of Darwen town centre in Lancashire and is owned and operated by United Utilities.

The improvement work at Earnsdale impounding reservoir included several ground breaking technical innovations for UK dam engineering, which included the use of soil mixing that Deep Soil Mixing Ltd carried out.

Working alongside GHD and the main contractor Askam our soil mixing solution was value engineered. This reduced the volume by 900m³, making significant cost savings and reducing the programme by eight weeks.

GHD said that Alan Williams, ICE North West Regional Chair noted that, “The improvement work at Earnsdale Impounding Reservoir included several ground breaking technical innovations for UK dam engineering, ….. It was this innovative approach that won it the Small Project of the Year 2018 award.”

John Lowery, Managing Director of Askam Civil Engineering, the principal contractor on the site, said: “The use of Deep Soil Mixing was an impressive solution due to the working conditions on this elevated and exposed site, which were on the whole extremely challenging….”

SMAS Worksafe Contractor

We are pleased to have gained a SMAS Worksafe certificate ( This means that we have met the SSIP core criteria recognised by the HSE and other SSIP accreditation schemes. Meeting the SSIP Core Criteria demonstrates that we are serious about H&S and have (and use) an effective H&S Management System to ensure that any work they are engaged in is, so far as reasonably practical, carried out without risk to health and safety.