CRCP Rehabilitation Design to Rectify Mine Subsidence Damage on M1 Motorway

This paper details the concrete reinforced concrete pavement rehabilitation design required to rectify the damage due mine subsidence on the M1 Motorway north of Cockle Creek Killingworth. Concrete pavement settlements had been monitored from July 2003 to November 2010 at a series of locations along the northbound and southbound carriageways. Additional pavement investigations were carried out in 2012, including GPR surveys and deflectograph testing along both carriageways. The maximum upward movement recorded at the site was 263 mm.

Based on the critical lateral pavement buckling load distributions and deflection analysis, an asphalt overlay thickness of 240 mm was recommended to mitigate possible further buckling due to temperature variations and to rehabilitate the reduction in pavement service life resulting from the disturbances in the pavement layers. Prior to the commencement of the asphalt overlay, all possible air voids detected by the GPR study were to be verified by coring before being cement grouting. Due to the various risk factors associated with the critical pavement buckling stresses, continual pavement settlement monitoring was recommended.