Patent Application
20240254879
Tunnel boring machines (TBMs) for excavating tunnels are known in the art. For example, U.S. Pat. No. 7,832,960, to Home et al., which is hereby incorporated by reference, discloses a tunnel boring machine having a cutterhead, a main support beam, a first, second, and third shield; and a ground conditioning work zone within the first shield, a gripper assembly, a segment erector arm for lining the tunnel, and at least one propulsion mechanism. The propulsion mechanism moves the cutterhead and the first and the second shield forward, while the third shield and the gripper assembly remain stationary. In U.S. Pat. No. 9,010,872, to Lenaburg, which is hereby incorporated by reference, a TBM is disclosed that has a cutterhead assembly rotatably mounted to a forward shield assembly through a cutterhead support assembly. The cutterhead support assembly receives a variable number of drive assemblies. The cutterhead support structure includes a housing portion that houses the main bearing assembly and a drive gear. A plurality of drive mount stations provide access to the drive gear.
The TBMs described in the above references are configured to bore a tunnel having a generally circular cross section. The curved tunnel crown of the circular cross section is advantageous to increase rock stability, reducing the need for ground support during tunnel construction. However, the curved tunnel floor of the circular cross section cannot be traversed by standard vehicles (e.g., trucks, trailers, rail cars, and other machinery) without first constructing a substantially flat invert (with invert segments, poured concrete, etc.) for travel by the standard vehicles.
TBMs can be configured with auxiliary cutter heads to bore tunnel having non-circular cross sections. For example, U.S. Pat. No. 5,110,188, to Kawai et al., which is hereby incorporated by reference, discloses a TBM with a plurality of circular cutters and one or more rocking cutters configured to bore a tunnel having a non-circular cross section. U.S. Pat. No. 10,539,016, to Su et al., which is hereby incorporated by reference, discloses a TBM having a main cutterhead assembly and a plurality of auxiliary cutterheads configured to excavate a tunnel having a non-circular cross section, where the main cutterhead assembly is configured to be movable vertically with respect to the auxiliary cutterheads.
The foregoing aspects and many of the attendant advantages of the claimed subject matter will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
The detailed description set forth herein connection with the appended drawings, where like numerals reference like elements, are intended as a description of various embodiments of the present disclosure and are not intended to represent the only embodiments. Each embodiment described in this disclosure is provided merely as an example or illustration and should not be construed as preferred or advantageous over other embodiments. The illustrative examples provided herein are not intended to be exhaustive or to limit the disclosure to the precise forms disclosed.
As will be described in more detail below, the present disclosure provides examples of a tunnel boring machine (TBM) configured to excavate a tunnel having a round arched top surface, substantially vertical sidewalls, and a substantially flat bottom surface (referred to herein as having the following tunnel shapes: “semicircular-arched,” “stilted-semicircular-arched,” “round-arched,” “horseshoe,” “U,” etc.). Embodiments of the TBMs of the present disclosure can be referred to herein as a “12% TBM,” which represents the approximately 12% additional tunnel boring excavation performed by the secondary cutterheads to create the substantially vertical sidewalls and flat bottom surface.
Embodiments of the 12% TBM described herein are expected to have several benefits over conventional TBMs. For example, most mining operations and many civil construction projects require flat-bottomed tunnel profiles to facilitate transportation of material, crew, and other necessities by standard vehicles (e.g., trucks, trailers, railcars, and other machinery). Conventional TBMs produce circular tunnel cross sections; however, TBMs of the present disclosure can excavate the remaining 12% of the tunnel using the same machinery as the primary boring operations, avoiding additional construction processes to prepare the tunnel for travel by standard vehicles. In creating the semicircular-arched tunnel, TBMs are a more efficient and productive method of tunnel excavation when compared with other conventional methods, such as drill and blast methods, backfilling the bottom of the round tunnel, or other mechanical methods (e.g., roadheaders).
The semicircular-arched tunnel profile created by the 12% TBMs of the present disclosure provide a semicircular-arched crown for natural support of the tunnel ceiling, with vertical sidewalls and a flat bottom that is ideal for transportation by standard vehicles. By using the same machinery as the primary boring operations, TBMs of the present disclosure can avoid frequent disruptions of other activities, such as excavation of the 12% of the tunnel by drilling and blasting, which is especially critical in mines which are sensitive to any interruption in ore extraction. Creating the semicircular-arched tunnel profile during primary boring operations also streamlines decommissioning, dis-assembly, retrieval, and demobilization of the site after tunnel boring operations are complete.
Although embodiments of the present disclosure may be described with reference to a configuration of a TBM suitable for producing semicircular-arched tunnel profiles, including the configurations shown in the FIGURES, one skilled in the relevant art will appreciate that the disclosed embodiments are illustrative in nature and therefore should not be construed as limited to such an application. It should therefore be apparent that the disclosed technologies and methodologies have wide application, and therefore may be suitable for use with many types of applications. Accordingly, the following descriptions and illustrations herein should not limit the scope of the claimed subject matter.
In accordance with one aspect of the present invention TBM for boring a semicircular-arched tunnel having a tunnel wall is provided. The TBM can include a main cutterhead assembly rotatably coupled to a front end of a cutterhead support on a main support beam, wherein the main cutterhead assembly is configured to rotate with respect to the cutterhead support about a primary axis that is aligned with a centerline of a semicircular portion of the tunnel; a plurality of gripper assemblies located rearward of the main cutterhead assembly, cutterhead support/forward shield, the gripper assemblies being configured to move between: a retracted position in which the gripper assemblies do not engage the tunnel wall; and an extended position wherein the gripper assemblies engage the tunnel wall to impart axial movement on the main cutterhead and to react to the boring forces of the tunnel boring machine. The TBM can further include a pair of secondary cutterhead assemblies slidably mounted to and disposed on opposite sides of the main support beam, wherein each of the pair of secondary cutter wheel assemblies have a carrier operably coupled to a drive system configured to rotate the secondary cutterhead assemblies about a secondary axis perpendicular to the primary axis; and at least one thrust cylinder configured to urge the pair of secondary cutterhead assemblies forwardly with respect to the main support beam independently of the main cutterhead assembly. In other embodiments, the main support beam of the TBM can have an upper portion aligned with the primary axis of the main cutterhead assembly, and a lower portion defining an elongate slot parallel to the main support beam, wherein the pair of secondary cutterhead assemblies engage the elongate slots to permit the secondary cutterhead assemblies to move longitudinally with respect to the main cutterhead assembly.
The secondary cutterhead assemblies 130 are installed behind the gripper shield 116 via carriers 134 that slide in the fore and aft direction within a slot 142 on a main/central beam 140 (“main support beam 140,” see
At the start of a boring cycle, the gripper shoes 117 are extended against side walls of the tunnel T by gripper shoe extension cylinders 118 (
The transfer of this high thrust through the rolling disc cutters of the main cutterhead 110 creates fractures in the rock, causing chips to break away from the tunnel face, creating the circular tunnel as shown in the main cutterhead boring area of
A unique aspect of the disclosed TBM 100 in accordance with embodiments of the present disclosure is included in the orientation and shape of the secondary cutterhead assemblies 130 operating behind the main cutterhead 110. The secondary cutterhead assemblies 130 can use an independent gripping system or can be tied to the TBM's main gripper system (e.g., the gripper shoes 117 of the gripper shield 116), or can include a secondary gripper system intended to permit the secondary cutterhead assemblies 130 to impart pressure on the secondary cutterhead boring area shown in
As shown in
Embodiments of the 12% TBM 100 can further include a muck removal system having unique aspects compared to conventional TBMs. In embodiments of the present disclosure, muck from the main cutterhead 110 is deposited via muck buckets 113 through a rotating action onto a belt conveyor inside TBM 100 and the main support beam 140 and includes an independent muck removal configuration in the peripheral conveyors 132. As the secondary cutterhead assemblies 130 excavate the final 12% of the tunnel, the muck buckets 133 (
The secondary cutterhead assemblies 130 can also be utilized during demobilization of the TBM 100, which is a critical aspect for many tunnel boring projects. In one embodiment, the secondary cutterhead assemblies 130 are configured to be modified by installing a rigid mounting system around the plurality of cutters 131, or by removing the secondary cutterhead assemblies 130 and replacing them with, e.g., a wheel track system, etc., to provide mobility for the entire TBM 100. The heavy load capacities of the secondary cutterhead assemblies 130 and axle 144 required for rock cutting, along with the independent control of the cutting rotation, allow the cutting wheels 134 to function as a wheel drive system allowing the machine to be driven out of the tunnel.
In the foregoing description, specific details are set forth to provide a thorough understanding of exemplary embodiments of the present disclosure. It will be apparent to one skilled in the art, however, that the embodiments disclosed herein may be practiced without embodying all of the specific details. In some instances, well-known process steps have not been described in detail in order not to unnecessarily obscure various aspects of the present disclosure.
Further, it will be appreciated that embodiments of the present disclosure may employ any combination of features described herein.
The present application may reference quantities and numbers. Unless specifically stated, such quantities and numbers are not to be considered restrictive, but exemplary of the possible quantities or numbers associated with the present application. Also in this regard, the present application may use the term “plurality” to reference a quantity or number. In this regard, the term “plurality” is meant to be any number that is more than one, for example, two, three, four, five, etc. The terms “about,” “approximately,” “near,” etc., mean plus or minus 10% of the stated value. For the purposes of the present disclosure, the phrase “at least one of A and B” is equivalent to “A and/or B” or vice versa, namely “A” alone, “B” alone or “A and B.” Similarly, the phrase “at least one of A, B, and C,” for example, means (A), (B), (C), (A and B), (A and C), (B and C), or (A, B, and C), including all further possible permutations when greater than three elements are listed.
It should be noted that for purposes of this disclosure, terminology such as “upper,” “lower,” “vertical,” “horizontal,” “fore,” “aft,” “inner,” “outer,” “front,” “rear,” etc., should be construed as descriptive and not limiting the scope of the claimed subject matter. Further, the use of “including,” “comprising,” or “having” and variations thereof herein is meant to encompass the items listed thereafter and equivalents thereof as well as additional items. Unless limited otherwise, the terms “connected,” “coupled,” and “mounted” and variations thereof herein are used broadly and encompass direct and indirect connections, couplings, and mountings.
Throughout this specification, terms of art may be used. These terms are to take on their ordinary meaning in the art from which they come, unless specifically defined herein or the context of their use would clearly suggest otherwise.
The principles, representative embodiments, and modes of operation of the present disclosure have been described in the foregoing description. However, aspects of the present disclosure, which are intended to be protected, are not to be construed as limited to the particular embodiments disclosed. Further, the embodiments described herein are to be regarded as illustrative rather than restrictive. It will be appreciated that variations and changes may be made by others, and equivalents employed, without departing from the spirit of the present disclosure.
Accordingly, it is expressly intended that all such variations, changes, and equivalents fall within the spirit and scope of the present disclosure as claimed.
This application claims the benefit of Provisional Application No. 63/482,011, filed Jan. 27, 2023, the disclosure of which is hereby incorporated by reference herein in its entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 63482011 | Jan 2023 | US |
