Finglas Slope Stabilisation and River Wall Underpinning

Jan 29, 2015

In recent months Byrne Looby have assisted Dublin City Council in the remediation of some slope stability issues and river wall undermining adjacent to the N2 Finglas Road in Dublin.

The scheme involves the stabilisation of a 50m long, 15m high, over steep slope adjacent to the N2 Finglas Road using soil nail stabilisation techniques. The slope is located above an open watercourse which is a tributary to the nearby River Tolka. In addition to the slope stabilisation works Byrne Looby have designed underpinning works to address localised scouring and undermining of the adjacent masonry river wall alongside an existing culvert.  The works are complex due to the steep nature of the slope, the slope location above the open watercourse and constraints on engineering solutions and construction works due to the local urban environment and location of nearby residential properties above the slope.

Byrne Looby progressed the design of the geotechnical solutions from the initial slope stability assessment, to site investigation and eventually onto detailed design, including tendering, procurement and contract administration on behalf of DCC.

Pictured: Soil Nail Installation using scaffold mounted drilling head                            Pictured: Temporary Scaffold Access for Soil Nail Installation

The preferable solution involved the installation of soil nail stabilisation measures, with self-drill soil nails drilled at 1.5m centres across the slope, with nail lengths of up to 12m installed. A shotcrete facing with aesthetic finish shall then be installed to ensure the long term stability of the slope and the residential properties above. 

Currently, the soil nail installation and underpinning works are nearing completion on site, with the permanent shotcrete facing and aesthetic finish to the completed in the coming weeks. Byrne Looby have regularly inspected the works to ensure the requirements of the specification are maintained on site, while also undertaking the role of PSDP.

Our geotechnical experience has proven critical in enabling the most effective solution to be identified and engineered to ensure buildable measures were chosen. In addition the works have caused minimal disturbance to the nearby landowners and operation of the adjacent Finglas Road.

Pictured: Clearing of slope vegetation and installation of crash deck and working platform over watercourse