Subsurface Investigation

The cost of accidental strikes on buried pipes services and cables is significant across the UK and Ireland. The UK Geospatial Commission state the economic cost is approximately £1.2 billion annually. Considering that the indirect cost of damaging utilities can be up to 30 times the direct cost, this puts direct cost of utility damage on contractors at £40 million in the UK alone. The lack of accurate location data has been identified as a key issue.  

Murphy Geospatial recognise the importance of accurate subsurface mapping to help reduce this risk and cost on a project. Our tailored services provide our clients with the geospatial certainty needed to plan, design, construct and operate with confidence. Accurate and up-to-date utility mapping supports trenchless utility operations thereby reducing the amount of intrusive investigation needed, such as slit trenching, and associated disruption to traffic.  

We have invested in industry-leading technology and are pioneering the use of mobile subsurface mapping techniques for the largest infrastructure projects in planning currently. We recognise the potential of intelligent BIM deliverables for subsurface project and will consult with our clients to demonstrate and deliver these benefits on their projects. 

The future of the subsurface mapping industry is ripe for innovation and continuous improvement. The nature of buried infrastructure means it is ideally suited to augmented reality applications allowing our survey deliverables to be visualised like never before. Machine learning and artificial intelligence promise efficiency gains in the processing of data. 

As the AEC industry begins to further appreciate the value of accurate subsurface mapping, Murphy Geospatial can assist our clients to procure a survey that is fit for purpose and provides an excellent return on investment. We consult with our clients at an early stage to recommend an approach that will return the expected level of certainty. We invest in the latest equipment and employ a range of expertise and software to analyse the output providing the highest-quality outcome.  

We have developed site and processing workflows to ensure that our field data is verified and our processed data is of the highest quality. We don’t just mark the ground, but apply post-processing workflows to ensure that our field data is cross-referenced against multiple data sources to increase the accuracy of the result. We use statutory records of the services through a site, ground penetrating radar, electromagnetic detection data and manhole surveys to ensure a comprehensive picture of the subsurface infrastructure is established. 

We promote the adoption of 3D outputs and visualisation in the industry, including augmented reality. Our new utility AR walkthrough service brings the modelling of the underground into your office environment providing an unparalleled understanding of what lies beneath. 

Underground Utility Mapping  

Designers and engineers can make sure their construction project is viable and safe prior to work by identifying the geographic location and depth of utilities and buried infrastructure through underground utility mapping. We work to the industry recognised PAS128 specification in order to locate, trace and map subsurface utilities, including pipes, cables, ducts, sewers, fouls, and surface water drainage. 

We utilise Magnetics, Ground Penetration Radar (GPR), Electromagnetic Location (EML), digital utility desktop services, advanced manhole and buried chamber mapping, and remote CCTV pipe mapping to cover large areas quickly and efficiently. Our surveyors are confined space certified for Working in Medium and High Risk Confined Spaces 

In addition, we provide CCTV inspection services to inspect underground drainage networks to provide condition reports and connectivity of drainage networks. Reports include pipe size and material, cover and invert level, as well as drainage connectivity and classification. 

PAS:128 and 256 Specifications 

We work to the BSI PAS:128 industry recognised specification for utility detection and mapping. We also record assets in accordance with the PAS256 specification for the recording as-laid buried assets. 

• Type D – Desktop utility records search – Extensive research contacting asset owners to obtain existing maps and related asset information to create a CAD drawing of the site to support planning and design.  

• Type C – Site reconnaissance – Onsite physical examination of manholes, trench scars, and exposed services to improve the accuracy of, and to validate, existing records. 

• Type B – Detection with geophysical techniques – Location and mapping of services using ground-penetrating radar (GPR) electromagnetic location (EML), and other geophysical methods to provide a detailed and accurate plan of subsurface utilities.  

• Type A – Site verification – Exposing buried services prior to site excavation to reduce the potential of utility damage, using slit trenching/ trial pit or vacuum excavation, potholing procedures. 

 

Geophysical Surveys 

Understanding the composition and condition of the ground beneath is an integral part of the construction and engineering process. Geophysical surveys are used to determine the physical properties of the ground materials in a non-intrusive manner. By applying electrical, magnetic, gravitational, seismic and other methods Murphy Geospatial can provide information about distinct subsurface boundaries and conditions that other methods cannot. With an accurate understanding of the nature of the ground, its density, elasticity, magnetic susceptibility and contamination, civil engineers are better equipped to assess risk and plan, design, and manage their project with certainty, reducing potential cost or project delays. Geophysical surveys allow economies of scale in acquisition as information for large areas of interest can be acquired efficiently as opposed to costly direct methods. 

NDT – Structural Inspection  

Non-destructive testing (NDT) is used as a low-cost solution to determine information on structural elements in-lieu of costly destructive methods. Murphy Geospatial use high-resolution ground-penetrating radar (GPR) and non-destructive testing (NDT) to safely locate embedment within structures and assess the steel reinforcement layout for design and construction purposes. The depth, size and cover of the rebar and post-tensioned cables is mapped prior to a contractor drilling, cutting or coring in floor slabs, walls or concrete columns, avoiding costly damage and delay to projects.