N4 Carrick-on-Shannon to Dromod Project - Phase 2 Ground Investigation

Tender description

The N4 Carrick-on-Shannon to Dromod Project aims to identify, evaluate, and resolve the transportation issues in the Carrick-on-Shannon / Cortober area, its environs, and the broader national road network – in particular the N4 corridor, as appropriate. The ground investigation comprises a combined geotechnical, geo-environmental and hydrogeological investigation, as part of Phase 2 for the N4 Carrick-on- Shannon to Dromod Project. In total, the ground investigation will comprise 31 No. cable percussive boreholes with rotary core follow-on to various depths, 11 No. rotary percussive boreholes to various depths, 29 No. groundwater monitoring installations and 1 No. combined groundwater and gas monitoring installation, 3 No. push in vibrating wire groundwater piezometers, 42 No. trial pits to a maximum depth of 4.5mBGL, 208 No. dynamic probes to a refusal, 6 No. window samples to refusal, 19.0km of electrical resistivity tomography profiles and 10.0km of 2D MASW survey. Soil, rock and groundwater samples are required from the trial pits, boreholes and monitoring wells for geotechnical and chemical testing and classification. The ground investigation scope shall be completed in stages to ensure reusability and other critical laboratory testing is completed within the required timeframe. To allow for this, boreholes at potential cut locations and all trial pits have been scheduled to be completed within the first 2 weeks of the field works. The locations to be completed as part of each stage is provided in Schedule 2 and must be adhered to. A number of proposed exploratory locations sit within the flood plains of the River Shannon and its associated tributaries and also in peat bog areas. Soft ground conditions that may be difficult to traverse will be encountered in these areas. The Contractor shall allow for appropriate measures to overcome difficult access due to soft or wet ground in the tender return.