BBV Sublot 1B Tunnel Grout Treatment

"Ground Treatment " The SC (Subcontractor) will assess the findings of the probe hole investigation and will develop the grout treatment strategy to be followed with a scope to minimize any excess water ingress during CP excavation and improve the ground stability.

Grouting operations will include stage permeation grouting on max 1m steps, with the use of packers.

Subcontractor based on ground and ground-water conditions as revealed from ground investigation (probe holes) shall develop the grouting strategy.

The strategy will include as a minimum but not exclusively the following: • A grouting pattern of primary and secondary on the periphery of CP profile • Drilling diameter, orientation, and lengths of each grouting hole • Bottom-up grouting stages with the use of packers.

The grouting stages should not exceed the length of 1m. • In case required (unstable ground) Subcontractor may need to make use of a tube a manchette TAM (sleeve pipes) system to perform the grouting.

In this case the strategy should be developed accordingly. • Mix design(s) of the grout injection • Max Pressure and max Volume criteria for stopping each grouting stage • Tertiary drilling holes in case primary and secondary do not reach the target criteria. • As built records grouting locations lengths stages grout consumptions and max pressure. "