Narva mnt roadway subsoil stabilization, restoration of soil bearing capacity and stopping the subsidence

A high-voltage cable was installed under the roadway using a closed method, as a result of which the bearing capacity of the soil was weakened and a sinkhole appeared on the roadway. One of the most recognized communications developer planned to install a new asphalt surface on the road in this area and wanted to ensure that the subsidence would not happen again in the future. In order to avoid large and long-term excavation works to improve the load-bearing properties of the soil, the customer turned to URETEK Baltic specialists to find a quick and cost-effective solution.

URETEK Baltic technical team found on site that it is necessary to start work at a depth of 3 meters to stabilize the subsoil of the roadway. For this, geopolymer resin was gradually injected in stages from 3 meters upwards. The two-component geopolymer first displaced the excess water in the subsoil, filled the voids in the soil created by the water, and then mixed with the soil (compacted the soil), multiplying its bearing capacity.

In the last stage, geopolymer was injected from the surface of the road to a depth of 1 meter. As a result, the subsided area of the roadway was raised by 1mm, which means that the soil had reached the required bearing capacity to raise it. The asphalt road is a light structure by its nature, so additional weights with a total weight of 3 tons were installed on the area of the subsided road to create counter pressure, to be sure of restoring the load-bearing properties of the soil.

URETEK Baltic team restored the bearing capacity of the subsoil in the area of the subsided roadway and stopped the possible further subsidence of the roadway at this location. It took 1,5 hours to complete the entire work – at the same time, tram and vehicle traffic was not stopped on the adjacent roadways.

With an alternative method, it would have taken 4-5 working days to carry out such work, during which all traffic on the road next to it would have had to be closed, and there would have been no complete certainty as to whether the subsoil was sufficiently compacted to prevent further subsidence in the future.

No less important is the fact that in the case of an alternative method, heavy trucks should have been involved in addition to excavation, but URETEK technology does not require them. Thus, we can contribute to reducing the CO² footprint by minimizing the negative impact on both people and the environment around us.