The Stockholm Bypass – A Grouting Design in Accordance with the Observational Methodpre-Excavation Grouting by Means of Rock Fissure Grouting with Cementitious Grouts-Video

Video Transcription

Video Summary

Mikael Kreutz presents an adaptive pre-grouting design developed for the Stockholm Bypass, a major hard-rock project with 18 km of tunnel along a 21 km stretch. In 2017, unexpectedly weak, water-conductive rock in the northern area made it difficult to meet strict water-ingress limits, prompting a redesign.<br /><br />The approach uses an observational method rather than relying rigidly on geological forecasts. Drilling data, water inflows, grout takes, and other field observations guide decisions about grouting class, additional rounds, and when to stop. Flowcharts and defined control and termination criteria help teams make consistent, transparent decisions, while allowing the design to adapt to actual ground conditions. The fan layout supports up to three grouting rounds, with additional measures for challenging zones.<br /><br />Although the method makes scheduling and contractor compensation harder to predict, Kreutz reports that it has worked well for the client and contractor and has informed other Stockholm projects. His central message: use observed data to adapt grouting in practice.

Keywords

adaptive pre-grouting

Stockholm Bypass

observational method

rock grouting

water ingress control