Subsurface Maps Dublin Centre

The subsurface geology of central Dublin is very important to the implementation of the Transport 21 initiative. A major expansion of Dublin’s transportation system is planned and a major element in it is the construction of underground rail lines. This will require extensive tunneling in the city centre area in particular. The nature of the subsurface geology is crucial to the engineering design and therefore to the ultimate cost of the project.

Information on the subsurface is largely dependent on data derived from boreholes and trial pits. Over many decades there has been extensive drilling in Dublin city centre. A key parameter is the depth to bedrock. Much of the earlier drilling was to relatively shallow depths which often did not meet bedrock, whereas in recent years the construction of larger buildings and the requirement for deep basements has meant that drilling has gone to greater depths, and bedrock has been intersected much more frequently. The National Geotechnical Borehole Database is a major dataset for the modeling of the subsurface geology in Dublin. A Depth to Bedrock Contour Map and a Rockhead OD Contour Map for central Dublin have been produced. In addition a 3-D model showing the elevation (metres OD Malin) of the buried bedrock surface has been produced. This modeling has been carried out using a dataset of 1,888 boreholes and trial pits which met rock out of a total of 5,222 digitised borehole and trial pit locations in central Dublin. New editions of these maps will be produced as more investigation locations are digitized.

Click on the link for more information on the Subsurface Geology of Central Dublin