Investigating the relationship between trenching practice and road deterioration

The functioning of modern societies relies on the successful performance of their infrastructure. In the UK, much of the buried infrastructure is located below the road surface, and routine maintenance of these requires networks to be accessed, commonly by open-cut methods. The open-cut operation in roads is likely to change the performance of the pavement structure and potentially how loads are transmitted, thereby affecting the buried infrastructure. The main objective of this paper is to investigate the impact of open-cut construction on the road, ground and buried infrastructure with the aim of improving the current associated guidelines. A fully instrumented site trial was undertaken where two pipes were installed using trenching in a road, with one reinstated according to the higher end of the UK specification and the other on the lower end of the specification. The trench reinstated according to the lower end of the specification experienced serviceability failure, where large settlements (approximately 70 mm) and deflections (up to 2000 mu m) were observed. The other trench also experienced distress, although to a much reduced level. This demonstrates that trenching, even when reinstated according to the higher end of the specification, still weakens the existing road locally.