TUNNEL BORING MACHINE

TUNNELIER

English Abstract

The present invention relates to a tunnel boring machine having a cutting head rotatably mounted on the end of a housing and being driven by a first motor means and a rotatable central auger for removal of soil from the cutting operation mounted in the interior of the housing, the central auger being driven by a second motor means to allow rotation of the auger independent of the rotation of the cutting head. The tunnel boring machine may also be provided with a rock crusher between the cutting head and the auger to reduce boulders encountered during the tunneling to a size to be able to be transported by the auger.

French Abstract

La présente invention concerne un tunnelier ayant une tête de coupe montée de façon rotative sur l'extrémité d'un boîtier et étant entraînée par un premier moyen de moteur et une vis sans fin rotative centrale pour l'enlèvement du sol de l'opération de coupe montée à l'intérieur du boîtier, la vis sans fin centrale étant entraînée par un deuxième moyen de moteur pour permettre la rotation de la vis sans fin rotative de manière indépendante de la tête de coupe. La machine de forage de tunnel peut également être pourvue d'un concasseur de pierres entre la tête de coupe et la vis sans fin pour réduire les blocs rencontrés au cours du creusement des tunnels à des dimensions permettant à la vis sans fin de les transporter.

Claims

I CLAIM:
1. A micro-tunnelling machine comprising a cylindrical housing having a
diameter of
about 2 meters or less, the housing having a cutting head rotatably mounted on
an end of
the housing and being driven by a first motor means; a rotatable central auger
for removal
of soil from the cutting operation mounted in the interior of the housing, the
central auger
being driven by a second motor means to allow rotation of the auger
independent of the
rotation of the cutting head; a rock crusher between the cutting head and the
auger to
reduce boulders encountered during tunneling to a size to be able to be
transported by the
auger; and a cone surrounding an intake end of the central auger, the cone
being provided
with spaced apart bars to limit the size of debris capable of entering the
central auger.
2. A micro-tunnelling machine as claimed in claim 1 wherein the cutting head
has crusher
bars mounted on an interior surface which cooperate with the spaced apart bars
of the
cone to provide a rock crusher to reduce large rocks to a size capable of
entering the
central auger.
3. A tunnel boring machine comprising a cylindrical housing having a cutting
head
rotatably mounted on the end of the housing, a rotatable central auger for
removal of soil
from a cutting operation mounted in the interior of the housing, a rock
crusher being
located between the cutting head and the auger to reduce boulders encountered
during the
tunneling to a size to be able to be transported by the auger and a cone
surrounding the
intake end of the central auger, the cone being provided with spaced apart
bars forming
part of the rock crusher to limit the size of debris capable of entering the
central auger.
4. A tunnel boring machine as claimed in claim 3 wherein the cutting head has
crusher
bars mounted on an interior surface which cooperate with the spaced apart bars
of the
cone to provide the rock crusher to reduce large rocks to a size capable of
entering the
central auger.

Description

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- 1
TUNNEL BORING MACHINE
FIELD OF THE INVENTION
The present invention relates to tunnel boring
machines and particularly to tunnel boring machines having
increased boring efficiency.
BACKGROUND OF THE INVENTION
Various apparatus have been used for removing earth in
a tunneling operation including the use of remotely controlled
tunnel boring machines which are basically augers, to the use of
digging machines such as back hoe type equipment. Tunnel boring
machines commonly in use employ a rotating toothed cutting head
at the end of a housing. As the cutting head rotates, the soil
is loosened and passes into the housing where it is removed. At
present there are two commonly employed techniques for removal
of the debris from the tunneling operation, augers and slurries.
The auger systems use a central auger which rotates with the
cutting head and moves the soil rearwardly and onto a conveyor
for removal. Auger tunneling machines use a single motor and
gear train in the jacking pit to rotate the cutting head and
auger simultaneously. Cutter head mining power loss on long
drives is tremendous which is often the limiting factor in
determining the lengthof the drive. Rotation of the cutting
head with the auger also means that head rotation cannot be
reversed as the auger will only move the spoil away from the
face when rotated in one direction. Moreover, auger systems
suffer drawbacks in some soil types. For example, loose or soft
soil may increase in volume when exposed to air. Thus when
drilling in loose soil, the soil may expand as it enters the
cutting head and auger system and cause flooding of the housing.
There have been machines developed which rely on the use of
flood doors or gates to attempt to control the rate of soil
transfer to maintain the pressure balance. Another problem is
encountered in soil containing large rocks, where the rocks may
be too large to enter the auger and may clog the removal of soil
from the cutting head. While some rocks may be able to enter

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2
the auger system, there is still the possibility that they may
become jammed in the auger system.
The other commonly employed method of removing soil
involves the use of slurry systems. In this method the machine
uses water to turn the excavated material into a pumpable fluid.
The water normally requires a 15% solid mixture to achieve
pumpable characteristics. Slurry-based machines have many
drawbacks especially in colder climates where the slurry may be
at risk of freezing during processing and disposal. In
addition, silicifying materials such as clays take time and a
lot of water to form into a slurry, whereas, sand courses absorb
and disburse the water. In some types of soils the high
pressure water may enlarge the diameter of the tunnel beyond the
machine diameter and cause unexpected cave-ins. Since one must
dispose of both a liquid and a solid waste, contaminated soils
are an increasing environmental problem.
SUMMARY OF THE INVENTION
The present invention relates to a tunnel boring
machine having a cutting head rotatably mounted on the end of a
housing and being driven by a first motor means and a rotatable
central auger for removal of soil from the cutting operation
mounted in the interior of the housing, the central auger being
driven by a second motor means to allow rotation of the auger
independent of the rotation of the cutting head.
In an aspect of the invention the tunnel boring
machine is provided with a rock crusher between the cutting head
and the auger to reduce boulders encountered during the
tunneling to a size to be able to be transported by the auger.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the present invention
are shown in the drawings wherein:

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Figure 1 is a perspective view partly in section of a
preferred embodiment of the tunnel boring machine according to
the present invention;
Figure 2 is a side elevation view of the tunnel boring
machine of figure 1;
Figure 3 is a front elevation view of the tunnel
boring machine of figure 1.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A preferred embodiment of the tunnel boring machine of
the present invention is shown in the figures generally at 10.
the machine 10 has a cylinder housing 12 sized based upon the
desired size of the tunnel. At the end of the housing is
located the cutting head 14 which generally includes cutting
bars 16 and flood doors or gates 18 to aid in controlling the
flow of the material removed from the tunnel face into the
interior of the housing 12. Once the material enters the
housing 12 it is carried away by a central auger 20 to be
disposed.
As shown in the figures, the cutting head 14 has a
face plate 22 to which the cutting bars 16 and flood gates 18
are attached, inversely conical side walls 24 and a base plate
26. The side wall 24 of the cutting head 14 is provided with a
series of radiating crusher bars 28 to form part of the rock
crusher system. Attached to the base plate 26 is a toothed ring
gear 30 which engages a complementary gear 32 driven by a first
motor 34 for rotation of the cutting head 14. The first motor
34 is attached to an annular base plate 36 attached along its
periphery to the housing 12. A bearing ring 38 is also attached
to the annular base plate 36 and cooperates with the ring gear
30 to form a cage 40 for ball bearings on which the cutting head
rotates. The plurality of seals 42 are provided around the
cutting head 14 for sealing the interior of the housing against
passage of dirt and debris.

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The central auger 20 is contained within an inner cone
44 which is fixed against rotation to the annular base plate 36.
Inner cone 44 forms part of the rock crusher of the boring
machine of the present invention. The wall of the inner cone 44
is constructed of a series of spaced apart crusher bars 46, the
spacing 48 between the bars 46 regulating the size of rocks
which will pass through and into the central auger system 20 as
will be explained further below. The central auger 20 is
rotated within the cone by means a second motor means in a
generally conventional manner separate from the first motor
means 34. In this way, the rotation of the central auger 20 can
be controlled independent of the rotation of the cutting head
14.
The tunnel boring machine 10 of the present invention
is preferably capable of articulated steering simultaneously in
both the vertical and horizontal directions. The steering is
accomplished by providing the housing 12 in two parts 12A and
12B, which are connected together through the use of
articulation cylinders 50. Preferably the machine 10 is
provided with three or four of these articulation cylinders 50
spaced along the interior circumference of the housing 12. One
end of the articulation cylinder 50 is attached to one part of
the housing 12A and a second end of the articulation cylinder 50
is attached to the second part of the housing 12B. A ring 52 of
reduced diameter is attached to housing 12B and extends into the
interior of housing 12A. Seals 54 are located between the ring
and the interior of housing 12A to seal against ingressive
material into the interior of the housing.
In operation, the first motor means 34 drives the
cutting head 14 at a suitable speed through the use of the motor
gear 32 and ring gear 30 to effect removal of material from the
face of the tunnel. Simultaneously the second motor means is
utilized to drive the central auger 20 to remove the material
entering the interior of the cutting head 14. Soils and small
rocks or pebbles pass directly through the spacing 48 between
the crusher bars 46 of the inner cone 44 and into the central
auger system 20 to be removed. Rocks and boulders which are

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larger than the size of the spacing are crushed by the rotating
crusher bars 28 on the cutting head 14 and the stationary
crusher bars 46 on the inner cone 44. This movement of the rock
or boulder between the two bars reduces the rock to a size which
5 allows it to pass through the spacing 48 and be removed by the
central auger system. Propulsion of the tunnel boring machine
is carried out in a conventional manner by pipe-jacking
technology.
10 By controlling actuation of the articulation cylinder
50, the cutter head 14 is capable of articulated steering of up
to about two to three degrees in both the vertical and
horizontal directions.
An important factor in the efficiency of tunneling
operations is the maintainence of earth presure balances.
Maintaining earth pressure balance is directly related to the
cutting head, propulsion and conveyor subsystem design and
operations. As the soil pressure varies over the length of the
drive, pressure sensors, in the cutter head near the face, will
monitor the pressure. The thrust force of the propulsion
system, auger rate of rotation and cutting head rate of rotation
can be varied independently based on the soil conditions
encountered. By adjusting the rate of auger rotation, cutting
head rotation and jacking force, pressure reduction of the waste
may take place inside the auger conveyor.
The tunnel boring machine of the present invention has
two independent drive trains, one controlling the rate of cutter
head rotation and the second controlling the rate of spoil auger
rotation. In this way the earth pressure balance can be
maintained without the use of slurry. The auger can be rotated
at a higher rate of rotation than the cutting head to permit the
spoil to expand inside the auger while maintaining a balanced
pressure at the face of the tunnel.
By driving the cutting head independent of the auger
conveyor, the cutting head is also permitted to rotate in both
directions while maintaining the rotation of the auger to remove

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spoil. This can be an advantage when trying to maintain roll
attitude and for navigation around certain obstacles. It also
provides for an additional operational mode when encountering
non-standard conditions particularly difficult boulders that
require crushing.
The present invention is particularly useful with
small diameter boring or drilling machines, particularly those
having diameters of 5 metres or less. The present invention is
particularly useful with boring machines which are known as
micro-tunnelling machines, which tipically have diameters in the
range of 1 to 2 metres, more particularly 1 to 1.5 metres in
diameter.
Although various preferred embodiments of the present
invention have been described herein in detail, it will be
appreciated by those skilled in the art, that variations may be
made thereto without departing from the spirit of the invention
or the scope of the appended claims.

Representative Drawing