Ground Penetration Radar investigations and surveys

Ground Penetration Radar investigations and surveys on the Lower Thames Crossing

We are carrying out a huge programme of ground investigations and surveys under the Thames and across Essex, Thurrock, and Kent, to help us design the new crossing.


Why we are doing it

These surveys will give us a clear picture of the locations and types of utilities in the road where we may be building. This will help us to improve our proposals and to develop our application for the Development Consent Order (DCO).

What we will do

We will be carrying out the works using equipment called a Ground Penetrating Radar. GPR uses radar pulses to create a profile of what the ground looks like beneath the surface.

The two types of GPR we will be using are:

Push GPR - Push GPR is similar to a lawnmower in appearance and is used on paths and walkways where an operative will push the equipment along to collect information.

Push GPR

Mobile GPR - Mobile GPR uses equipment attached to a van or tractor. This will be used on the roads to carry out the non-invasive surveys. We will be doing the majority of the works using this method.

Mobile GPR

What to expect

Our priority is to carry out this programme of work in a way that will have the smallest possible impact on the community.

The works will be carried out in two phases with the first phase involving signage and an escort and the second phase involving some traffic management. (Please see the map below for more detail)

  • The works are non-invasive and will not cause any noise disruption.
  • Due to the nature of the works, there will be flashing lights which are used on our works vehicles for the safety of both the workforce and the road users. As the works are mobile, the vehicles will be continuously moving, so any disruption caused by these will be kept to a minimum.
  • Access to properties will be maintained throughout the duration of the works.
  • At times, there will be lane closures with two-way traffic lights in place. This is required for the safety of both the work force and the road users.
  • The working hours for the mobile GPR (vehicles travelling at 10 mph/15kph) will take place during day time off-peak hours, Monday to Friday or carried out at night-time in high traffic areas, between 8pm and 6am, Monday to Friday.
  • We expect the works to continue until mid-December.

Map Key

  • Push GPR – Equipment pushed on foot. Traffic escorted.
  • Mobile GPR (signs/escort) – Survey van followed by traffic management vehicle. Some signage.
  • Mobile GPR (traffic lights) – Lane closures with temporary traffic lights or stop go boards.
  • Mobile GPR (ring management) – At J29 on M25 we will close the inner ring and then the outer ring of the roundabout. Survey completed by van.
  • Mobile GPR (mobile works on high speed roads) – Multiple traffic management vehicles, approx. 5 or 6 at intervals pushing traffic across lanes. These will all be on nights. Limited to A2/M2 and M25. Survey completed by van.

Frequently asked questions

Where will the work take place?

Work will take place in various locations between the B186 in North Ockendon, Essex and the A2/M2 near Gravesend, Kent.
(See map above)

Work will start in October 2019 through to February 2020. (See map above for dates of work at each location)

The works will not cause any noise disruption, as they are non-invasive surveys.

There will be a mobile working unit with the equipment mounted on to the back of the van. At times, where lane closures are required we will use traffic management including cones and traffic lights, while the surveys are done. People in protective clothing and equipment will also be present.

At times, we will have mobile working in place which will involve a van travelling at 10mph while the surveys are done. At times, for safety reasons, we will need to install temporary traffic lights with a lane closure which may cause some disruption, but we will endeavour to keep these to a minimum. Access properties will be maintained throughout the works.

The sites that we are carrying out surveys will remain as they were prior to us starting works due to the non-invasive nature of the surveys.

The surveys will enable us to identify the type and location of utilities infrastructure.

We have used previous records to obtain data, but we need to obtain more up-to date information to ensure that we can build the Lower Thames Crossing safely and efficiently with accurate information.

These surveys will take 6 months.

Balfour Beatty will be carrying out these works, alongside CAT Surveys who specialise in carriageway surveys.

Balfour Beatty staff will be wearing protective clothing and equipment which will be branded with LTC, working on behalf of Highways England.

The surveys will help us plan utility diversions if required. The surveys will enable us to identify the type and location of utilities infrastructure.

This will help us to improve our proposals and to develop our application for the DCO.