From the supply of amenities (water, gas, etc) to highspeed internet, network reliability is of utmost importance to any utility owner. One of the top reasons why unplanned disruptions occur in Singapore is utility strikes from Earthworks.
As-built databases are only indicative of the general location of existing utilities. Exact spatial coordinates are lacking or even lost to time. There is heavy dependence on trial holes to confirm the alignment of subsurface utilities before starting the construction of the new utilities. However, the increase in trial holes exponentially raises the risk of utility damages, increasing project costs to the contractors and project owners.
In severe cases, projects could be stopped by the authorities and re-routing is performed at the contractor’s expense.
Subsurface Utility Engineering (SUE) is a discipline of engineering that qualifies the investigation levels for subsurface utilities. By performing Subsurface Utility Mapping (SUM), the alignment of utilities like power and telco cables, gas, water, sewer pipelines and drains, can be accurately done.
With accurately mapped utilities, new projects can be planned to accommodate the existing subsurface infrastructure. This enables project owners to better identify clashes and conflicts during the design phase, mitigating significant risks downstream, like cost overruns and long project delays.
SUE allows for the reduction of unnecessary utility relocations and significantly decreases the likelihood that existing utilities will be damaged in new construction projects.
SUM is not new to Singapore. We are used to doing numerous trial holes to map out the location of utilities, but this is an expensive and slow process. Each trial hole can easily cost $2,500 - $3,500 depending on the scale of the project.
It is estimated per lane-km of trial holes at 30m intervals will take about 1 working month with a cost of $100,000. The data that it yields is incomplete and non-continuous, leaving room for site discoverable.
With a combination of plants maps (QL D), site recce (QL C) and GPR (QL B), we produce a Geo-located Utility Map. The alignment and width of the utilities are also recorded.
Results were verified during trenching works to be immensely accurate. The existing utilities exposed during the construction of the new utility lined up exactly with the Geo-located Utility Map HSC produced before beginning Earthworks.
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