Using blast energy as an effective technology to provide subgrade stability in road construction

Abstract

Drilling and blasting technology is considered to be one of the most efficient and cost-effective ways to increase the bearing capacity of soft soils which form the subgrade of road embankments. This study investigates blast energy as a means of creating vertical sand drains in a section of Moscow-Saint-Petersburg Motorway M-11 (construction 2018) which crosses the Kolomenka River and is located in a swampy area. Geophysical and geological engineering tests were conducted, they included monitoring of pore pressure modification in soft soils as well as geodetic monitoring of settlement levels. The findings showed that the applied technology quickly allowed a large bulk of sandy soils (more than 500 thousand cubic meters) to compact in the subgrade of the road as a result of generation of excessive pore pressure. No other technology could have been used due to the presence of an embedded bulk of soft soils and swampiness of the site. Decreasing deformations of the subgrade and CPTU data revealed that the subgrade of the road embankment was compacted. This fact was also confirmed by geophysical tests. Drilling and blasting technology is very effective from an ecological and economic perspective in comparison with other technologies. In addition, this study highlights the importance of preserving swamp systems in order to protect river sources.