|
Single Shield LOVAT TBMs consist of a Cuttinghead, Forward Shell, Stationary
Shell, Trailing Shield as well as the Trailing Gear & Gantry. Machines can
be designed to convert in order adapt to changing ground conditions.
There are three broad categories of Lovat Pressurized TBMs
1.Semi-Pressurized Mode - When the tunnel face requires some
support the TBM is operated by utilizing LOVAT’s patented Mucking Ring and
Pressure Relieving Gate (PRG) technology. When the PRGs are engaged, pressures
of up to 2 bar can be maintained in the cuttinghead chamber.
Operation of
the PRG can be manually or automatically controlled.
2. Earth Pressure Balance Mode - This excavation mode
provides continuous support to the tunnel face by balancing the inside earth and
water pressure against the thrust pressure of the machine. The ground excavated
by the cuttinghead is mixed and accumulated under pressure in the cuttinghead
chamber, and is then extracted by a Screw Conveyor. The pressure in the
cuttinghead chamber is controlled by balancing the rate of advance of the
machine and the rate of extraction of the excavated material by the Screw
Conveyor.
Manual or automatic operation of the EPB system is possible
through the integrated PLC and computer-control systems.
3. Slurry Pressure Balance Mode – The Slurry excavation mode
provides continuous support to the tunnel face by balancing earth and water
pressure in the in-situ soil with a pressurized bentonite slurry. This
excavation mode provides continuous support to the tunnel face by balancing the
inside earth and water pressure against the slurry pressure of the machine. The
ground excavated by the cuttinghead is mixed and accumulated under pressure in
the cuttinghead chamber, and is then extracted by a Screw Conveyor. The pressure
in the cuttinghead chamber is controlled by balancing the rate of advance of the
machine and the rate of extraction of the excavated material by the Screw
Conveyor.
For a
typical Configuration, please click here.
For a sample Product Sheet, please click here.
|
