Tunnel Boring Magazine has this synopsis of the project:
The East Side Access project in New York City involves some of the most complex civil construction in recent years. The project involves constructing new tunnels and station caverns in the heart of Manhattan with its pricey high-rises and maze of buried utilities and foundations â€“ not to mention existing rail traffic in and around historic Grand Central Terminal.
The jet grouting for this project is being performed by specialty geotechnical contractor Hayward Baker. The work is being performed at break-in/break-out areas where the TBM’s will enter or exit the run, at havens and to stabilize an existing slurry wall constructed under a separate contract. [Source: Tunnel Business Online. Image: Tunnel Business Online]