Warsaw Metro Project C21 Station Soil Bottom Plug Using Big Diameter Jet Grouting Technique

Video Transcription

Video Summary

The presentation describes jet-grouting work for a Warsaw metro extension, including a 120-foot-deep, six-foot-thick plug beneath a large station excavation. About 4,500 columns were installed, with verticality the main technical challenge and drilling the main production bottleneck. The team combined electrical-resistivity measurements with painted-rebar checks to verify column diameter and set production parameters. Two rigs produced roughly 10 columns each per day; only about 1% required redrilling for deviation. Testing showed permeability and strength met specifications, and total water ingress was below the project limit. The speaker emphasizes careful verification, conservative design, and a little luck.

Keywords

jet grouting

Warsaw metro

deep excavation

verticality control

electrical resistivity