WO2019142000A1

WO2019142000A1 - A tunnel boring apparatus, a tunnel boring machine, and a method of boring tunnels

Info

Publication number: WO2019142000A1
Application number: PCT/GB2019/050149
Authority: WO
Original assignee: Strada Design Limited; Ng, Matthew
Priority date: 2018-01-19
Filing date: 2019-01-18
Publication date: 2019-07-25
Also published as: GB2570317A; GB201800899D0

Abstract

The present invention provides a tunnel boring apparatus (10) for a tunnel boring machine (1), comprising a rotatable drill head (12) having a boring face; a plurality of drill elements (14) mounted to the boring face; wherein the plurality of drill elements include a plurality of water hammers (14a).

Description

A Tunnel Boring Apparatus, A Tunnel Boring Machine,

And A Method Of Boring Tunnels

The present invention relates to a tunnel boring apparatus. In particular, the present invention relates to a tunnel boring apparatus for a tunnel boring machine. The present invention also relates to a tunnel boring machine with a tunnel boring apparatus and a method of boring tunnels.

Tunnel boring machines (TBM) are generally known and are used to excavate tunnels through rocks, sand, or other earth formations.

In the so-called Rotary Bit Tunneling Method, a typical TBM has a rotatable cutter head at the front of the machine. Cutter elements such as cutter blades or cutter bits are mounted to the forward facing front face of the cutter head. As the cutter head rotates, the cutter blades or bits grind and scrape at the earth formation to dislodge material from the earth formation. An auger or vacuum system is usually used to clear cuttings (i.e. dislodged earth formation) from the front of the TBM and conveyor belt or suction system is used to transport the cuttings to the rear of the TBM to be removed from the tunnel by truck or train. Hydraulic pistons or rams are commonly used to provide the necessary forces required to drive the cutter head of the TBM forward whilst the TBM is anchored to the walls or casing of the tunnel.

One disadvantage with such known TBMs is that a great deal of force is required to drive the cutter head of the TBM forwards during tunnel excavation operations, in particular in hard rock formations. An associated disadvantage is that the large forces generate noise and vibration, which are undesirable, especially when excavating tunnels near the ground surface which often leads to environmental and surface property damage. Another disadvantage with known TBMs is that even state of the art cutter blades and bits are prone to wear and require frequent replacements during tunnel excavation operations. Furthermore, due to the high rotation rate and forces required, the operating costs from fuel consumption is typically very high.

There is therefore a need for improvements in TBMs to address one or more of these and other disadvantages. According to an aspect of the present invention, there is provided a tunnel boring apparatus for a tunnel boring machine, comprising a rotatable drill head having a boring face; a plurality of drill elements mounted to the boring face; wherein the plurality of drill elements include a plurality of water hammers.

In embodiments, the drill head is configured to rotate about a longitudinal axis.

In embodiments, the drill elements are arranged in a pattern across the boring face such that the drill elements sweep over an area defined by the boring face with one complete rotation of the drill head.

In embodiments, each of the plurality of water hammers has an inlet for receiving a liquid drive fluid, and wherein the inlets of the water hammer is coupled to a common drive fluid supply. Preferably, each of the plurality of water hammers has an outlet configured to exhaust the drive fluid.

Preferably, the tunnel boring apparatus further comprises an interconnecting network of hoses or pipes coupling the inlets of the plurality of water hammers to the common drive fluid supply.

Alternatively, the boring face is divided into a plurality of sections concentric about the longitudinal axis, and wherein the water hammers of the respective sections are configured to be driven at different rates. Preferably, the tunnel boring apparatus further comprises a plurality of manifolds corresponding respectively to the plurality of sections of the boring face, each having an inlet and a plurality of outlets, the inlet being configured to couple to the drive fluid supply and each outlet is configured to couple to one of the plurality of water hammers; wherein the water hammers of each section are coupled to the corresponding manifold.

Preferably, the tunnel boring apparatus further comprises a plurality of flow meters, each couple to a manifold and configured to regulate flow of the drive fluid from the manifold to the water hammers coupled to the manifold.

In embodiments, the tunnel boring apparatus further comprises a fluid circulation system configured to pump exhaust drive fluid back to the drive fluid supply. In embodiments, the circulation system includes a filtration system configured to remove particulates from the exhaust drive fluid.

In embodiments, the plurality of water hammers are closed loop water hammers. Preferably, the tunnel boring apparatus further comprising a flushing system configured to provide a flushing fluid at the boring face.

According to another aspect of the present invention, there is provided a method of boring tunnels, comprising using a tunnel boring machine having a tunnel boring apparatus, wherein the tunnel boring apparatus includes a rotatable drill head having a boring face and a plurality of drill elements mounted to the boring face, wherein the plurality of drill elements include a plurality of water hammers; supplying a drive fluid to each of the plurality of water hammers; and driving the tunnel boring machine through earth formations.

In embodiments, driving the tunnel boring machine through earth formations comprises anchoring the tunnel boring machine; rotating the tunnel boring apparatus; driving the tunnel boring apparatus towards a direction of excavation.

According to yet another aspect of the present invention, there is provided a tunnel boring machine.

Embodiments of the present invention will hereinafter be described by way of examples, with references to the accompanying drawings, in which:

Figure 1 is an illustration of a tunnel boring machine;

Figure 2 is a front perspective illustration of a tunnel boring apparatus;

Figure 3 is a rear perspective illustration of a tunnel boring apparatus;

Figure 4 is a cross-sectional view of a tunnel boring apparatus;

Figure 5 is an illustration of a water hammer; Figure 6 is an illustration of a variant of a water hammer;

Figure 7 is a see-through rear perspective illustration of a tunnel boring machine; and Figure 8 is a front face view of a tunnel boring apparatus.

Referring to Figure 1 , an embodiment of a tunnel boring machine (TBM) in accordance with the present invention is shown. The TBM 1 comprises the tunnel boring apparatus 10 at the front and a trailing section 2 behind the tunnel boring apparatus 10. In operation, to use the TBM 1 to bore tunnels, a rotational driver (not shown in Figure 1) in the trailing section 2 coupled to the tunnel boring apparatus 10 rotates the tunnel boring apparatus 10. Pistons 3 in the trailing section 2 forces the tunnel boring apparatus 10 forwards in the direction of excavation. To give the TBM 1 purchase during operation, anchors 4 in the trailing section 2 are deployed to maintain the position of the TBM 1 whilst the tunnel boring apparatus 10 is being driven forwards.

As will be apparent to the skilled person, grippers or other suitable mechanisms in the trailing section 2 provide the necessary purchase to anchor the TBM 1 in position and the pistons 3 may be hydraulic or any other suitable type of forward motion

mechanism. In some embodiments, the pistons 3 may be replaced by tracked, rails, or wheels.

In the embodiment depicted in Figure 1 , once the pistons 3 have reached the limit in how far they can drive the tunnel boring apparatus 10 forwards, the anchors 4 are released, allowing the whole TBM 1 to be advanced forwards. Once the TBM 1 has advanced forwards, the anchors 4 are dropped again. In some embodiments of the TBM 1 , a bulkhead section or a chamber is provided behind the tunnel boring apparatus to collect cuttings produced during operation. An auger and a conveyor system or a vacuum extraction system are optionally provided in the trailing section 2 of the TBM 1 to transport the cuttings away.

Referring to Figures 2 to 4, an embodiment of a tunnel boring apparatus 10 in accordance with the present invention is shown. As shown in Figure 2, the tunnel boring apparatus 10 is generally configured to be installed at the front of the TBM 1. In a broad embodiment, the tunnel boring apparatus 10 comprises a drill head 12 with a boring face (i.e. the face oriented towards the direction of excavation) and a plurality of drill elements 14 mounted to the boring face, at least a plurality of which are water hammers 14a. In some embodiments such as the embodiment shown in Figure 2, each drill element 14 is a water hammer 14a.

In embodiments such as the embodiment shown in Figure 2, the drill head 12 includes a housing 16 and a support structure 18 within the housing 16. At one end of the housing 16, hereinafter designated as the forward end, a generally circular front panel provides the aforementioned boring face on which the drill elements 14 are mounted. The drill head 12 also comprises a coupling mechanism 20 at the other end of the housing 16, hereinafter designated as the rearward end, configured to couple to the rotational driver such as a motor on the TBM 1. In operation, the rotational driver drives the drill head 12 to rotate about a longitudinal central axis A parallel to the direction of excavation, perpendicular to the boring face. In one embodiment, the coupling mechanism 20 is a clutch type mechanism. This enables convenient engagement and disengagement between the drill head 12 and the rotational driver.

Using water hammers in place of conventional rotary cutter elements has several advantages. Water hammers require significantly less driving force in order to carry out the same tunnel excavation operation as compared to conventional cutter elements, meaning that less force is required to drive the tunnel boring apparatus 10. Consequently, cheaper, more efficient, and less expensive hydraulic pistons or other drive systems would be sufficient. For example, the drill head 12 in accordance with embodiments of the present invention is typically driven with 20kNm as compared to conventional TBMs, which require lOOkNm. With an overall reduction in the forces required to drive the tunnel boring apparatus 10 forwards, less noise and vibration are generated. Longer bearing life and longer drill bit life are also possible with the use of water hammers. Water hammers are also much more efficient at excavation operations, typically able to excavate 80mm to 100mm per rotation of the drill head 12 (between 5m to 10m per hour of excavation). Using water hammers in place of conventional rotary or roller cutter elements therefore enables a slower rotation rate of the drill head 12, increasing the efficiency of the tunnel boring apparatus 10. Water hammers also require signification lower rotation speed. Typically, the drill head 12 of the tunnel boring apparatus 10 in accordance with embodiments of the present invention is driven at 1rpm to 2rpm as compared to rotary or roller cutter heads with conventional rotary or roller cutter blades, which are usually driven at 5rpm to 10rpm and are able to excavate hard rock at only 10mm to 20mm per rotation of the cutter head (an average of 0.4m to 0.5m per hour of excavation).

Referring to the embodiment shown in Figure 3, a plurality of water hammers 14a are mounted on the support structure 18 within the housing 16. To facilitate the mounting of the water hammers 14a to the boring face, the front panel of the housing 16 is provided with openings corresponding to the number of water hammers 14a and the water hammers 14a are mounted on the support structure 18 such that the head of each water hammer 14a (explained in more detail below) extends through a corresponding opening. In this arrangement, each water hammer 14a functions as a hammer drill. As the drill head 12 rotates during operation, the water hammers 14a repeatedly strike the earth formation through which the TBM 1 is being driven. In embodiments, the locations of the water hammers 14a across the boring face are arranged such that in one complete rotation of the drill head 12, the water hammers 14a excavate an area corresponding substantially to the area of the boring face. In some other embodiments, the water hammers 14a are arranged such that the same area is excavated in less than one complete rotation of the drill head 12. For example, in one embodiment, the water hammers 14a are arranged along a radius of the boring face such that the water hammers 14a sweep over an area corresponding to the boring face in one complete rotation of the drill head 12. In another embodiment, the water hammers 14a are arranged along a diameter of the boring face such that the water hammers 14a sweep over an area corresponding to the boring face in half a rotation of the drill head 12. In other embodiments, the water hammers 14a are arranged over the boring face in a pattern that facilitates coupling and connects that will be explained in more detail.

The housing 16 in embodiments such as the embodiment shown in Figures 2 and 3 is generally cylindrical and made of a strong material such as steel or aluminium. In the depicted embodiment, the housing 16 is formed from a generally tubular body portion 16a and a separate front panel 16b. In other embodiments, the housing 16 is formed as a unitary component. It will also be appreciated that the housing 16 may be of any other suitable construction apparent to the skilled person. The support structure 18 of the depicted embodiment is constructed from welded panels of the same or similar material as the housing 16 and provides strength to the housing 16 as well as the means to mount the water hammers 14a within the housing 16. It will be appreciated by the skilled person that the housing 16 may be other shapes and the support structure 18 may have other form. For example, in some embodiments, the support structure 18 may be constructed as a frame or from interlocking panels instead of welded panels. It will also be appreciated that the housing 16 and support structure 18 may be constructed from materials other that steel or aluminium.

Figure 5 shows an example of a water hammer 14a suitable for use with the tunnel boring apparatus 10 in accordance with embodiments of the present invention. It will be appreciated by the skilled person that the water hammer 14a shown in Figure 5 may be replaced by any other suitable water hammer. It will also be appreciated that the details of the water hammer 14a are provided for completeness.

As shown in Figure 5, the water hammer 14a includes a body portion 142 and a drill bit 144 at one end of the body portion 142. At the other end of the body portion 142 is an inlet 146 for receiving a liquid drive fluid such as water from an external main drive fluid supply. The inlet 146 leads to a conduit 148 through the body portion 142 that provides a flow path for the drive fluid to the drill bit 144. The mechanism of the drill bit 144 is similar to a pneumatic hammer drill and will be apparent to the skilled person. In operation, drive fluid from the main drive fluid supply is received at the inlet 146 at a suitably high pressure and flows to the drill bit 144 through the conduit in the body portion 142. The drive fluid drives the operation of the drill bit 144 in a similar way as air drives the operation of a pneumatic hammer drill. The drill bit 144 of the example shown in Figure 5 has an outlet 150 to allow the drive fluid to exhaust through the boring face. In some embodiments, the tunnel boring apparatus 10 has a circulation system (not shown in Figure 1), comprising suitable pipes and/or hoses and a pump to circulate the exhaust drive fluid back to the main drive fluid supply. The circulation system, which is provided at the trailing section 2 of the TBM 1 in embodiments, optionally includes a filter system configured to clean the recycled drive fluid, which may contain mud, cuttings, or other undesirable particulates when exhausted through the water hammer 14a. In one embodiment, the filter system includes a filtration unit that receives the exhaust drive fluid, removes particulates above a predetermined size (for example a size above which damage to the water hammers 14a would be caused), and returns the cleaned drive fluid to the pump. This enables the drive fluid to be reused without the need for a constant supply of fresh drive fluid. In variants of the example of Figure 5, the water hammer 14a is configured to operate in a closed loop manner. In these variants, one of which is shown in Figure 6, instead of the exhausting the drive fluid through the outlet 150 in the drill bit 144 and out through the boring face of the boring apparatus 10, the exhaust drive fluid is returned up the water hammer 14a via a return conduit 149. In the variant shown in Figure 6, the return conduit 149 leads to an outlet 150 provided on the body portion 142, which is in turn connected to the aforementioned circulation system. In another variant (not shown), the return conduit 149 leads back to the top end of the water hammer 14a, and the outlet 150 is provided at this end of the water hammer 14a. Using closed loop water hammers in the herein described tunnel boring apparatus 10 is advantageous when the tunnel boring machine 1 includes a large number of water hammers 14a. For example, with fifty or more water hammers 14a, the volume of water exhausted through the boring face may become too much for the auger/conveyor or vacuum system to handle. Using closed loop water hammers 14a relieves the auger/conveyor or vacuum system of this burden.

In embodiments in which the drill elements 14 are closed loop water hammers 14a, a flushing system is optionally provided. The flushing system is configured to provide a flushing fluid to the boring face to remove dust and/or cuttings during operation of the tunnel boring machine 1. The flushing system includes jets (not shown) provided at the boring face. The jets are connected to a separate supply of flushing fluid located for example at the trailing section 2 of the TBM 1. The flushing fluid may be water, air, or any other suitable fluids or a combination there of. The pressure of the flushing fluid supplied to the jets is adjusted to a suitably sufficient level to cause a slurry to form during operation so that the auger/conveyor or vacuum system is not overloaded.

Referring to Figure 7, in an embodiment in which each drill element 14 is a water hammer 14a, each water hammer 14a is oriented with the inlet 146 towards the rearward end of the housing 16 and the drill bit 144 towards the forward end of the housing 16 extending through the boring face. An interconnecting network 22 of hoses, or pipes, or other suitable fluid conduits connects the inlets 146 of the water hammers 14a. The interconnecting network 22 is in turn connected to the main drive fluid supply via a common connection. In this arrangement, the water hammers 14a are supplied with drive fluid from a single source, thereby simplifying the construction and costs of the apparatus 10. In some embodiments, means for controlling the flow rate of the drive fluid from the main drive fluid supply to the interconnecting network 22 are included in the tunnel boring apparatus 10. For example, in one particular embodiment, a variable flow rate valve is provided to vary the flow rate of the drive fluid into the interconnecting network 22 as well as turning the flow on or off. A flow meter is optionally provided alongside the variable valve to monitor the flow rate of the drive fluid. As will be apparent to the skilled person, the distribution of the water hammers 14a over the boring face may be arranged in ways so as to reduce the complexity of the interconnecting network 22 of hoses, or pipes, or other suitable fluid conduits connecting the inlets 146 of the water hammers 14a. It will also be apparent to the skilled person that the interconnecting network 22 arrangement may also be provided in embodiments in which a plurality of the drill elements 14 are water hammers 14a.

In variants of the embodiment of Figure 7 (not shown), the tunnel boring apparatus 10 includes a manifold having an inlet and multiple outlets provided generally at the rearward end of the tunnel boring apparatus 10. The inlet of the manifold is coupled to the main drive fluid supply and each of the outlet is connected to the inlet 146 of one of the water hammers 14a. The means for controlling the flow rate of the drive fluid is optionally integrated into the manifold.

In some other variants, the boring face is divided into a number of concentric sections and the water hammers 14a of the different sections are driven at different rates. For example, in a particular variant, the tunnel boring apparatus 10 includes a number of manifolds corresponding to the number of sections.

In the example variant shown in Figure 8, the boring face is divided into three concentric sections, an outer section 24a, a middle section 24b, and an inner section 24c, each centered on the longitudinal axis A. Three manifolds, an outer manifold, a middle manifold, and an inner manifold, are provided. The inlets 146 of the water hammers 14a mounted on each section are connected to the outlets of a respective manifold. Specifically, the inlets 146 of the water hammers 14a of the outer section 24a are coupled to the outlets of the outer manifold, the inlets 146 of the water hammers 14a of the middle section 24b are coupled to the outlets of the middle manifold, and the inlets 146 of the water hammers 14a of the inner section 24c are coupled to the outlets of the inner manifold. In turn, the inlets of the manifolds are connected to the main drive fluid supply. Corresponding means for controlling the flow rate of the drive fluid as described above are provided for each manifold, either integrally or external to the manifolds, to control the flow rate of drive fluid delivered to each section of water hammers 14a. In this arrangement, the flow rate of drive fluid to the water hammers 14a of the different sections, and thereby the strike rates of the water hammers 14a of the different sections, can be controlled individually to enable one section of water hammers 14a to have a different strike rate than another section of water hammers 14a. For example, during operation of the TBM 1 , the drill head 12 rotates such that a water hammer 14a radially closer to the rotational axis A revolves around the rotational axis A at a lower tangential velocity than a water hammer 14a radially further from the rotational axis A. To accommodate this difference in tangential velocity, the manifolds and/or the flow rate control means can be configured to deliver a higher flow rate of drive fluid to a radially outer section and a lower flow rate to a radially inner section. More generally, the flow rate can be configured to increase with radial distance from the central rotational axis A of the drill head 12. Controlling the drive fluid flow in this manner facilitates a more even excavation across the area of the boring face as the TBM 1 is driven forward.

As illustrated in Figure 8, the water hammers 14a are divided into three sections. The skilled person will appreciate that the water hammers 14a in other variants may be divided into more or fewer sections.

In a particular embodiment of the above-described tunnel boring apparatus 10, a delivery manifold, a return manifold, and a flushing manifold are provided. The delivery manifold is configured to receive drive fluid at high pressure from the main drive fluid supply and to deliver the drive fluid to the water hammers 14a, also at high pressure. The return manifold is coupled to the outlets 150 of the water hammers 14a and is configured to deliver the large volume of exhaust drive fluid, at low pressure, to the above-mentioned circulation system. The flushing manifold is optionally provided in conjunction with the flushing system and is configured to deliver the flushing fluid to the jets of the flushing system.

In the embodiments described above, the tunnel boring apparatus 10 is generally cylindrical and is configured to rotate about a longitudinal central axis A. However, it will be appreciated that the tunnel boring apparatus 10 may have any other suitable shape and may be configured to rotate about an off-centre axis.

Embodiments of the present invention have been described with particular reference to the examples illustrated. However, it will be appreciated that variations and modifications may be made to the examples described within the scope of the appending claims.

Claims

Claims:

1. A tunnel boring apparatus (10) for a tunnel boring machine (1), comprising: a rotatable drill head (12) having a boring face;

a plurality of drill elements (14) mounted to the boring face;

wherein the plurality of drill elements (14) include a plurality of water hammers

(14a).

2. A tunnel boring apparatus (10) as claimed in claim 1 , wherein the drill head (12) is configured to rotate about a longitudinal axis (A).

3. A tunnel boring apparatus (10) as claimed in claim 1 or 2, wherein the drill elements (14) are arranged in a pattern across the boring face such that the drill elements (14) sweep over an area defined by the boring face with one complete rotation of the drill head (12).

4. A tunnel boring apparatus (10) as claimed in any preceding claim, wherein each of the plurality of water hammers (14a) has an inlet (146) for receiving a liquid drive fluid, and wherein the inlets (146) of the water hammer (14a) is coupled to a common drive fluid supply.

5. A tunnel boring apparatus (10) as claimed in claim 4, wherein each of the plurality of water hammers (14a) has an outlet (150) configured to exhaust the drive fluid.

6. A tunnel boring apparatus (10) as claimed in claim 4 or 5, further comprising an interconnecting network (22) of hoses or pipes coupling the inlets (146) of the plurality of water hammers (14a) to the common drive fluid supply.

7. A tunnel boring apparatus (10) as claimed in claim 4 or 5, wherein the boring face is divided into a plurality of sections concentric about the longitudinal axis (A), and wherein the water hammers (14a) of the respective sections are configured to be driven at different rates.

8. A tunnel boring apparatus (10) as claimed in claim 7, further comprising a plurality of manifolds corresponding respectively to the plurality of sections of the boring face, each having an inlet and a plurality of outlets, the inlet being configured to couple to the drive fluid supply and each outlet is configured to couple to one of the plurality of water hammers (14a); wherein the water hammers (14a) of each section are coupled to the corresponding manifold.

9. A tunnel boring apparatus (10) as claimed in claim 7, further comprising a plurality of flow meters, each couple to a manifold and configured to regulate flow of the drive fluid from the manifold to the water hammers (14a) coupled to the manifold.

10. A tunnel boring apparatus (10) as claimed in any one of claims 5 to 9, further comprising a fluid circulation system configured to pump exhaust drive fluid back to the drive fluid supply.

11. A tunnel boring apparatus (10) as claimed in claim 10, wherein the circulation system includes a filtration system configured to remove particulates from the exhaust drive fluid.

12. A tunnel boring apparatus (10) as claimed in any preceding claim, wherein the plurality of water hammers (14a) are closed loop water hammers.

13. A tunnel boring apparatus (10) as claimed in claim 12, further comprising a flushing system configured to provide a flushing fluid at the boring face.

14. A method of boring tunnels, comprising:

using a tunnel boring machine (1) having a tunnel boring apparatus (10), wherein the tunnel boring apparatus includes a rotatable drill head (12) having a boring face and a plurality of drill elements (14) mounted to the boring face, wherein the plurality of drill elements (14) include a plurality of water hammers (14a);

supplying a drive fluid to each of the plurality of water hammers (14a); and driving the tunnel boring machine (1) through earth formations.

15. A method as claimed in claim 14, wherein driving the tunnel boring machine (1) through earth formations comprises:

anchoring the tunnel boring machine (1);

rotating the tunnel boring apparatus (10);

driving the tunnel boring apparatus (10) towards a direction of excavation.