Strength and stiffness properties of stonewool used as cloudburst reservoir under roads

Abstract

With the climate change, Copenhagen has seen an increase in cloudbursts. During the cloudbursts, sewer systems overflow and result in flooded basements and overspill of untreated water into the harbour. A solution to the limited capacity is to make cloudbursts reservoirs to delay the rain water filling the sewer system. At Langelands Plads in Copenhagen, a reservoir has been established using the stonewool product Rockflow. The Rockflow is installed under two roads and a space used for recreational purposes. Based on monotonic and cyclic laboratory tests, material parameters and appropriate numerical model for the anisotropic material were established. In-situ measurements of the stiffness during and after installation at Langelands Plads consisted of plate load tests and falling weight deflectometer tests together with rutting measurements. The in-situ measurements were statistically processed and back-analysed to confirm the initial material parameters and model. Further, the in-situ measurements are ongoing at appropriate intervals to monitor the performance of the road.