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Lower Thames Crossing Ground Investigation Phase 3 

Shortlisted for Brownfield Awards Category 3: Best Adaptation to Covid-19 

Lower Thames Crossing Ground Investigation Phase 3 

This submission presents the controls and adaption to working practises applied on Phase 3 of the Lower Thames Crossing Ground Investigation project to manage the risk posed by the coronavirus pandemic. The project was classified as a critical infrastructure project by the Government and remained fully operational throughout the projects 10-month duration, with AECOM delivering the project to program. 


This submission focuses on AECOM’s approach to delivering the most intensive ground investigation project since the M25 whilst operating within a global pandemic. AECOM took early robust action and applied organisational and technology solutions to ensure the health of the 500 plus workforce, their family’s and third parties who may have been affected by our undertakings.

Project Background 

The Highways England (client) Lower Thames Crossing project consists of the construction of twin-bore tunnels under the River Thames and a new dual carriageway, extending between Junctions 28 and 30 of the M25 to the A2, east of Gravesend.

AECOM, Principal Contractor within Perfect Circle as a joint venture delivered Phase 3 of the ground investigation, having previously completed Phases 1 and 2. The project held critical infrastructure status as announced by the UK Government at the commencement of the Covid-19 pandemic and remained fully operational throughout the UK lockdowns until completion in January 2021. 


Exemplary Best Practice

AECOM, like many global organisations, was actively tracking coronavirus developments within Wuhan, China and other countries and had developed forecasts of the potential coronavirus impact within the UK. With this information AECOM were able to implement a robust coronavirus mitigation policy and specification for the project in early March 2020. Ensuring that the project establishment and the project staff were Covid-19 secure.    

A collaborative approach between AECOM, Highways England, LTC Cascade and all AECOM Sub-Contractors delivered an innovative and collective response to the pandemic which resulted in a best practice Covid-19 response. This collaborative approach ensured that coronavirus mitigation measures were designed into the project compound, welfare arrangements and work tasks, instead of being an afterthought.  It removed any obstacles which could have potentially impacted effectiveness.

The AECOM Lower Thames Crossing Coronavirus Policy focused on three core elements to ensure an effective mitigation strategy, 

  1. Early diagnosis of potential cases, isolation of potential cases and tracing of potential contacts.

  2. Social distancing of all project staff and limiting interactions to small segregated worker bubbles.

  3. Facility and personal hygiene standards.

To deliver this policy, innovative and technology solutions were used, together with collaborative project team planning to achieve a project which remained fully operational throughout 2020. The project recorded low numbers of positive coronavirus cases and zero third generation coronavirus transmission, demonstrating the effectiveness of AECOM mitigation measures.  


At the start of 2020 AECOM were completing Lower Thames Crossing Ground Investigation Phase 2 having been on site since June 2019. Phase 2 had been completed on most of the land and offshore packages, however two main areas of work remained.  These were being completed simultaneously with the preparations and planning works within early contractor involvement for Phase 3, with on site works commencing early March 2020. 

Managing Potential Coronavirus Cases 


Thermometric Units installed across the project provided daily face recognition touchless temperature readings for all staff. The Thermometric Units prompt staff to take their temperature as they approach. Audible conformation of a healthily reading is confirmed or an alert is issued when the temperature is above 37.8oC, an alert is also issued to the Site Manager. This system provided reassurance to the workforce and project team that physical health checks can and were being completed.

Individuals who declare or show symptoms were isolated within dedicated well ventilated first aid / covid rooms. Within which were clear instructions and provision to wash / sanitise their hands, put on a face mask and contact details for the responsible AECOM staff member. AECOM ensured that;

  • Details of their symptoms were recorded and testing advice given.

  • Details were taken in reference to their contacts over the past 48hrs.

  • The individual was able to get home or to medical facilities if required.

  • A record of the potential case was recorded and the cases are tracked and confirmed positive / negative.

  • The first aid room and any other potential affected areas underwent a deep clean.

  • All project package staff were informed of the potential case.

When testing capabilities allowed, all potential Covid-19 cases were reported onto AECOM’s IndustrySafe platform and were tracked through the UK testing process to confirm results. Prior to confirmed results being received or prior to testing being readily available, all suspected cases were treated as positive.

Following any suspected and then confirmed Covid-19 case, AECOM SHE Professionals would manage the communication and reporting process, including to regulatory authorities. Assisting the project team, AECOM international Occupational Health Team undertook a contact tracing process to identify potential transmission targets and ensure all were tested.

Segregation of Workforce

The Lower Thames Crossing Project has a 14 mile long boundary that has been separated into five work packages to aid delivery. This characteristic of the project leant itself to further isolating each package to ensure the limitation of cross package movement. In turn reducing the risk of a potential project wide Covid-19 impact in the event of an outbreak. At the peak of UK Covid-19 lockdown, further limitations were placed on the work packages, ensuring;

  • Non-essential site staff worked from home, or where only part time attendance was required, reducing the number of days they worked on site.

  • Senior Manager, Director, Client, and Client Agent package visits where paused.

  • Security enforced a strict authorised access policy, only allowing staff who held package clearance access, utilising AECOM Msite security system.

  • Any cross-package movement of staff were authorised by a single staff member and isolated working was implemented eliminating contact with existing package staff.

Through the duration of the project, following government advice AECOM worked to various standards, adjusting our controls when AECOM, Industry and Government guidance were published and updated.

Social Distancing 

All project welfare was upgraded as the project moved from the completion of Phase 2 and into Phase 3 as a result of the coronavirus planning. This allowed welfare to be specified to meet the requirements of coronavirus social distancing, while also implementing other control measures such as staffing numbers, shifts, etc. Office and Canteen layouts were designed to ensure that enough seating is provided, while ensuring it promoted space and complied to social distancing guidelines.


Some tasks required working closer than 2m and where this was the case a hierarchy of controls was followed based on;

  • Duration

  • Frequency

  • Same or different person(s)

  • Direction of interaction

  • Effort of operation. 

As a minimum, for all tasks where closer than 2m working is required, the working teams would be set with limited changes in personnel, together with the use of coronavirus PPE.

Each project package managed social distancing risks associated with briefings in one of two ways, where the compound layout permitted it, briefings would be held outside ensuring 2m social distancing is maintained before, during and after the briefing. Alternatively holding supervisor briefings via digital iAuditor or Microsoft Teams systems.


All AECOM project vehicles were fitted with dividing screens to permit two persons to use the vehicle, reducing the amount of additional parking required across the project and to reduce the carbon footprint from the initial arrangement to drive in separate vehicles. 

Within areas of the project with high footfall, the digital social distancing hardware ZoneRanger was used by all staff. The ZoneRanger system provides an audible and vibrating alert to the wearer when they encroach within 2m of another person outside of their working bubble, those within their working bubble do not produce an alert. 

A total of 1,137 litres of CO2 were injected into the waste at the active locations (Figure 4).  The average rate of injection over the duration of the trial (normalized to unit surface area of the waste) ranged between 0.21-1.28 kg/ with the slower rate (BH_CO2_01A) attributed to the presence of cohesive made ground at surface.

Cost Effectiveness

Through AECOM’s approach to coronavirus management and the risk mitigation investment that was made, this major infrastructure project remained on program. This feat would have been impressive within a normal environment given the size and geography of the scope of works, so to achieve this within a global pandemic, without project interruption, speaks volumes for the commitment of the entire team and how everyone on the project stepped up to manage coronavirus. 

Compliance with legislation, codes and guidance

Although AECOM initially developed the Lower Thames Crossing Coronavirus Policy before official Government or Industry guidance was issued, this was updated following every issue and revision of the Covid-19 Government and CLC guidance.

Effective Stakeholder Engagement

In the early stages of the pandemic, AECOM formed the Lower Thames Crossing Coronavirus Group attended by Project / Managing Directors from the contractors working on the project and LTC Cascade, with the aim to overcome some of the significant challenges posed by coronavirus. 

The attendees of the Lower Thames Crossing Coronavirus Group collectively and individually looked at the key issues to identify innovations which allowed works to continue on the project, these included, but were not limited to;

  • Installing screens on drilling rigs between Lead Driller and Support Operative where 2m social distancing could not be achieved.

  • The use of power filtered air visors for drilling staff.

  • Prefabricating monitoring point protection to allow it to be transported and installed maintaining social distancing.

  • Staggered shift patterns implemented to prevent staff gatherings at the start and end of the day, and during breaks.

  • Installation of additional welfare provisions and controls on maximum occupancy.

As part of any suspected case management, the workforce staff were informed of the potential case, their contacts and work areas attended by the potential case within the past 48 hours and following testing, conformation of the outcome. This open communication proved invaluable to ensuring worker wellbeing and a team management approach to coronavirus. Feedback from workforce surveys highlighted that staying informed of AECOM’s actions and responses aided in workforce wellbeing through the reduction of anxiety and stress.  



Ensuring that the project facilities were sterile and that those using them observe rigorous hygiene routines, aided to minimise the risk of virus transmission across the project. AECOM ensured that cleaning staff and provisions were increased to ensure two welfare cleans per day as a minimum, together with canteens being cleaned after each bubble uses it and all touch points cleaned hourly. 

All persons entering the project sanitised their hands as part of the site access procedure. Following parking vehicles and before accessing welfare all staff washed their hands at one of the wash stations and frequently throughout the day, as staff enter and leave welfare or use the facilities they sanitised or washed their hands.

Workforce Support 

In addition to the immediate health risks posed by coronavirus, there were organisational issues relating to Covid-19. These included the commuting and accommodation arrangements for staff, procuring safety equipment and PPE, and the accessibility of training. 

AECOM worked with the contractors and local businesses to ensure that requirements such as accommodation, parking, equipment, etc. were resolved, and used our national procurement team to support training and hard to obtain PPE. 


Real environmental/economic/social benefit

Where possible through reduction of vehicle movements and waste control, environmental benefits were introduced into AECOM coronavirus controls, however the primary focus was on health and response which limited the benefits within this area. The social value of AECOM’s approach, both within the progression of the project to aid economic recovery and the continued focus on staff wellbeing throughout 2020 will have added significant value directly to those involved and the local businesses.

A robust, sustainable and defensible solution

The results of how AECOM adapted to work within the coronavirus pandemic speaks for itself, there are few projects that continued to operate without pausing works due to coronavirus and fewer still that delivered a major infrastructure project, to high quality standard, on program. 

When visited by an HSE Inspector completing a covid compliance inspection they stated “the covid controls and their implementation were the most natural they had seen on any project”.

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