A TBM capable of off-center loading and its tunneling method

Abstract

This invention discloses a TBM capable of off-center loading and its tunneling method, relating to the field of TBM tunneling technology. It includes a support shield, the front end of which is connected to a front shield via a propulsion cylinder. A cutterhead is mounted at the front end of the front shield, and a stabilizer is mounted on the upper part of the front shield. Windows are respectively opened on both sides of the support shield, and support shoes are installed within these windows. Each support shoe includes a support cylinder, a push plate, a shoe block, and a reaction force auxiliary fixture. The support cylinder is fixedly installed inside the support shield and is a bidirectional cylinder. Push plates are fixedly installed at both ends of the support cylinder, and a shoe block is installed on the side of the push plate away from the support cylinder. The beneficial effect is that by adding the reaction force auxiliary fixture, the support shoe can provide support both in an airborne state and in a non-airborne state, meeting the reaction force support requirements and avoiding the situation where the support shoe cannot tighten the tunnel wall under off-center loading, leading to difficulty in controlling the shield's attitude.

Description

Technical Field

[0001] This invention relates to the field of TBM tunneling technology, and in particular to a TBM capable of off-center loading tunneling and its tunneling method. Background Technology

[0002] During the TBM tunneling process, the excavation of the first-level drainage gallery of the plant needs to enter the water diversion and drainage gallery for construction. After the water diversion and drainage gallery construction is completed, the excavation will return to the first-level drainage gallery for construction. Because the excavation routes of the water diversion and drainage gallery and the first-level drainage gallery of the plant overlap, eccentric loading tunneling is required.

[0003] Taking into account the TBM's functional characteristics and route layout, and avoiding simultaneous construction of eccentrically loaded tunneling and curved tunneling, the TBM will enter the lower water diversion tunnel for excavation at the intersection of the powerhouse drainage gallery and the water diversion tunnel. After excavating 25m, it will retreat to the intersection and excavate 50m of the powerhouse drainage gallery under eccentric load before retreating back to the intersection to excavate the lower water diversion tunnel.

[0004] When the TBM was excavating at the intersection of the water diversion tunnel and the powerhouse drainage gallery, a large cavity existed between the excavated tunnel side and the TBM support shoe. Due to the limited stroke of the support shoe's hydraulic cylinder, it was unable to tightly support the tunnel wall. Therefore, auxiliary tools needed to be added at this location to fill the gap between the support shoe and the tunnel wall to meet the requirements of the tunneling reaction force. Summary of the Invention

[0005] The purpose of this invention is to provide a TBM capable of off-center tunneling and its tunneling method in order to solve the above-mentioned problems.

[0006] The present invention achieves the above objectives through the following technical solutions:

[0007] A TBM capable of off-center loading tunneling includes a support shield. The front end of the support shield is connected to a front shield via a propulsion cylinder. A cutterhead is installed at the front end of the front shield, and a stabilizer is installed on the upper part of the front shield. Windows are opened on both sides of the support shield, and support shoes are installed in the windows. Each support shoe includes a support cylinder, a push plate, a shoe block, and a reaction force auxiliary fixture. The support cylinder is fixedly installed inside the support shield and is a bidirectional cylinder. Push plates are fixedly installed at both ends of the support cylinder, and a shoe block is installed on the side of the push plate away from the support cylinder. The reaction force auxiliary fixture includes a fine-tuning cylinder, a support plate, and a positioning rod. A fine-tuning cylinder is fixedly installed on the side of the shoe block away from the support cylinder. The fine-tuning cylinders are distributed in a matrix on the shoe block. The end of the fine-tuning cylinder away from the shoe block is connected to the support plate via a ball joint. A positioning rod is fixedly installed between the support plate and the shoe block to support the support plate so that its outer surface is flush with the outer surface of the support shield.

[0008] Preferably, the support shoe is divided into a non-airborne area and an airborne area on both sides relative to the supporting cylinder, and the structures on both sides are configured as follows:

[0009] On the non-air zone side: a connecting block is fixedly installed on the side of the push plate away from the support cylinder, and a connecting groove is opened on the side of the shoe block near the support cylinder. The connecting block on the push plate is connected to the connecting groove on the shoe block.

[0010] On the air-cushioned side: The reaction force auxiliary tooling also includes an extension block disposed between the push plate and the shoe block. The side of the extension block near the push plate has a connecting groove. The side of the extension block away from the push plate has a connecting block fixedly installed. The side of the shoe block near the extension block has a connecting groove identical to the connecting groove on the extension block. The side of the push plate away from the support cylinder has a connecting block identical to the connecting block on the extension block fixedly installed.

[0011] Preferably, when there is one extension block on one side of the air-filled area, the connecting block on the push plate is connected to the connecting groove on the extension block, and the connecting block on the extension block is connected to the connecting groove; when there are at least two extension blocks, the connecting block on the push plate is connected to the connecting groove on the extension block, the connecting blocks and connecting grooves on two adjacent extension blocks are connected, and the connecting block on the extension block is connected to the connecting groove.

[0012] Preferably, the connecting block and connecting groove on the non-air zone side and the connecting block and connecting groove on the air zone side have the same structure. The connecting block has a top groove inside, and a top block is movably disposed in the top groove. Movable grooves are respectively opened on the upper and lower sides of the top groove, and a locking block is movably disposed in the movable groove. One end of the locking block extends into the top groove, and the other end of the locking block extends out of the outer surface of the connecting block. Both ends of the locking block are rounded. The top block has an inclined surface corresponding to the position of the locking block to facilitate the ejection of the locking block. A screw is threaded through the middle of the top block. The screw is threaded to the top block. Both ends of the screw are respectively connected to the connecting block through bearings. The screw is driven by an external drive structure. The connecting groove has a locking groove corresponding to the position of the locking block.

[0013] Preferably, both the extension block and the push plate are provided with an external drive structure. The external drive mechanism includes a transmission groove, a worm gear, a worm, and an internal hexagonal socket. A screw corresponding to the extension block extends into the extension block and is fixedly installed with a worm gear. A transmission groove is opened inside the extension block corresponding to the position of the worm gear. A worm gear meshing with the worm gear is also provided in the transmission groove. One end of the worm gear extends to the outer surface of the extension block and is fixedly installed with an internal hexagonal socket for easy rotation. A screw corresponding to the push plate extends into the push plate and is fixedly installed with a worm gear. A transmission groove is opened inside the push plate corresponding to the position of the worm gear. A worm gear meshing with the worm gear is also provided in the transmission groove. One end of the worm gear extends to the outer surface of the push plate and is fixedly installed with an internal hexagonal socket for easy rotation.

[0014] A tunneling method for a TBM capable of off-center loading includes the following steps:

[0015] Step S1: The TBM advances to the intersection of the first tunnel route and the second tunnel route;

[0016] Step S2: Excavate 25m along the route of the first tunnel;

[0017] Step S3: Retreat 25m to the intersection of the first tunnel route and the second tunnel route;

[0018] Step S4: Excavate 15m along the second tunnel route with eccentric loading;

[0019] Step S5: Continue excavating along the second tunnel for 35m;

[0020] Step S6: Retreat 50m to the intersection of the first tunnel route and the second tunnel route;

[0021] Step S7: Push along the first tunnel for 25m without air;

[0022] Step S8: Proceed with the construction of the second tunnel.

[0023] Preferred steps for the TBM rollback process are as follows:

[0024] a. The front shield stabilizer extends to support the tunnel wall;

[0025] b. The hydraulic cylinder extends to push the support shield and the rear assembly backward one stroke;

[0026] c. The front stabilizer is retracted, and the support boots of the support shield extend out of the support cavity wall;

[0027] d. Rotate the cutter head to advance the hydraulic cylinder for recovery;

[0028] e. The cutter head and front shield move backward one stroke;

[0029] f. If the support boot has a support point, repeat a to e; if the support boot has no support point, an extension block is added between the push plate and the boot block on one side of the air zone, and the hydraulic cylinder is finely adjusted to push the support plate to support the tunnel wall, thereby achieving the reaction force support of the support shield, repeat a to e.

[0030] g. Return to the specified position.

[0031] Preferred: The specific steps for off-center tunneling of a TBM are as follows:

[0032] a. Tighten the internal hexagon on the push plate on one side of the air zone to activate the worm gear drive;

[0033] b. The screw rotates, the top block moves in the top groove, the locking block loosens and disengages from the locking groove, the support cylinder retracts, and the connecting block on the push plate separates from the connecting groove on the shoe block.

[0034] c. An extension block is added between the push plate and the shoe block. The connecting block on the extension block is inserted into the connecting groove on the shoe block, and the connecting block on the push plate is inserted into the connecting groove on the extension block. By turning the corresponding internal hexagon, the screw is rotated and the top block moves along the screw, thereby using its inclined surface to push the locking block into the slot, completing the locking of the connecting block and the connecting groove, and realizing the installation of the extension block.

[0035] d. Select the number of extension blocks to be installed according to the conditions of the airspace, and fine-tune the hydraulic cylinder to extend the support plate on the tunnel wall to achieve reaction force support;

[0036] e. The cutterhead rotates, and the propulsion cylinder pushes the front shield and cutterhead forward to achieve off-center tunneling;

[0037] f. After the off-center excavation is completed, turn the Allen wrench to remove the added extension block.

[0038] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0039] 1. By adding reaction force auxiliary tooling, the support shoe can provide support in both air-to-air and non-air-to-air states, thus meeting the requirements for reaction force support and avoiding the situation where the support shoe cannot hold the tunnel wall tightly under uneven load, making it difficult to control the shield's attitude.

[0040] 2. By setting extension blocks, they can be added when needed and removed when not needed, meeting the requirements for reuse, reducing material costs, and the installation operation can be completed inside the support shield, eliminating the need for manual entry into the tunnel to set up reaction supports, thus reducing the risk factor;

[0041] 3. By setting up a matrix distribution of fine-tuning hydraulic cylinders and using ball joints to push the support plate, it can arbitrarily adapt to the curved surface of the tunnel wall and meet the support requirements;

[0042] 4. By setting a positioning rod for the support, the support plate can be quickly restored to its original position, making it convenient to use. Attached Figure Description

[0043] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of the installation structure of a TBM capable of off-center tunneling as described in this invention.

[0045] Figure 2 This is an AA-direction cross-sectional view of an off-center load tunneling method as described in this invention.

[0046] Figure 3 This is a schematic diagram of the internal structure of a TBM connecting block capable of off-center tunneling as described in this invention.

[0047] Figure 4 This is a schematic diagram showing the location of one side of the overhead zone and the other side of the non-overhead zone of a TBM capable of off-center tunneling according to the present invention.

[0048] Figure 5 This is an indication diagram of the first and second tunnel routes of the tunneling method of a TBM capable of off-center loading according to the present invention.

[0049] Figure 6 This is a flowchart of a tunneling method for a TBM capable of off-center loading, as described in this invention.

[0050] Figure 7 This is a schematic diagram of the working principle of a TBM capable of off-center tunneling as described in this invention.

[0051] The annotations in the attached figures are explained as follows:

[0052] 1. Cutter head; 2. Front shield; 3. Propulsion cylinder; 4. Support shield; 5. Support shoe; 51. Push plate; 52. Shoe block; 53. Fine-tuning cylinder; 54. Support plate; 55. Positioning rod; 56. Support cylinder; 57. Connecting groove; 58. Connecting block; 581. Top groove; 582. Movable groove; 583. Locking block; 584. Top block; 585. Screw; 586. Transmission groove; 587. Worm gear; 588. Worm; 589. Internal hexagon; 59. Extension block; 6. Window. Detailed Implementation

[0053] In the description of this invention, it should be understood that the terms "center," "longitudinal," "lateral," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. In addition, the terms "first," "second," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, features defined with "first," "second," etc., may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0054] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation", "connection", and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal connection of two components. For those skilled in the art, the specific meaning of the above terms in this invention can be understood through the specific circumstances.

[0055] The present invention will be further described below with reference to the accompanying drawings:

[0056] Example 1

[0057] like Figures 1-2 As shown, a TBM capable of off-center loading tunneling includes a support shield 4. The front end of the support shield 4 is connected to a front shield 2 via a propulsion cylinder 3. A cutterhead 1 is installed at the front end of the front shield 2, and a stabilizer is installed on the upper part of the front shield 2. Windows 6 are opened on both sides of the support shield 4, and support shoes 5 are installed in the windows 6. The support shoes 5 include a support cylinder 56, a push plate 51, a shoe block 52, and a reaction force auxiliary fixture. The support cylinder 56 is fixedly installed inside the support shield 4. The support cylinder 56 is a bidirectional cylinder. Push plates 51 are fixedly installed at the left and right ends of the support cylinder 56, and a shoe block 52 is installed on the side of the push plate 51 away from the support cylinder 56. The reaction force auxiliary fixture includes a fine-tuning cylinder 53, a support plate 54, and a positioning rod 55. A fine-tuning rod is fixedly installed on the side of the shoe block 52 away from the support cylinder 56. Hydraulic cylinders 53 and fine-tuning cylinders 53 are distributed in a matrix on shoe block 52 to ensure stable support force. The end of the fine-tuning cylinder 53 away from shoe block 52 is connected to a support plate 54 through a ball joint. When the TBM is under eccentric load, the support plate 54 is more likely to fit against the curved surface of the tunnel wall where the support shoe 5 is in contact. A positioning rod 55 is fixedly installed between the support plate 54 and shoe block 52 to support the support plate 54 so that its outer surface is flush with the outer surface of the support shield 4. This ensures that the support plate 54 will not be irregular in state or protrude from the support shield 4 and cause wear after the TBM retracts the support cylinders 56 and fine-tuning cylinders 53 during normal tunneling. Pressure sensors are respectively installed on the outer surface of the support plate 54 and the end of the positioning rod 55 to monitor whether the support state and retraction state of the support plate 54 are in place.

[0058] Example 2

[0059] like Figures 1-2 As shown, the difference between this embodiment and Embodiment 1 is that the support shoe 5 is divided into a non-airborne area and an airborne area on both sides relative to the support cylinder 56, and the structural settings on both sides are as follows:

[0060] On the non-air zone side: A connecting block 58 is fixedly installed on the side of the push plate 51 away from the support cylinder 56, and a connecting groove 57 is opened on the side of the shoe block 52 near the support cylinder 56. The connecting block 58 on the push plate 51 and the connecting groove 57 on the shoe block 52 are connected in cooperation.

[0061] On the side of the air-cushioned area: The reaction force auxiliary tooling also includes an extension block 59 set between the push plate 51 and the shoe block 52. The side of the extension block 59 near the push plate 51 has a connecting groove 57. The side of the extension block 59 away from the push plate 51 has a connecting block 58 fixedly installed. The side of the shoe block 52 near the extension block 59 has a connecting groove 57 that is the same as the connecting groove 57 on the extension block 59. The side of the push plate 51 away from the support cylinder 56 has a connecting block 58 that is the same as the connecting block 58 on the extension block 59.

[0062] When there is one extension block 59 on the side of the air-filled area, the connecting block 58 on the push plate 51 is connected to the connecting groove 57 on the extension block 59, and the connecting block 58 on the extension block 59 is connected to the connecting groove 57. When there are at least two extension blocks 59, the connecting block 58 on the push plate 51 is connected to the connecting groove 57 on the extension block 59, and the connecting blocks 58 and connecting grooves 57 on two adjacent extension blocks 59 are connected, and the connecting block 58 on the extension block 59 is connected to the connecting groove 57. The connecting block 58, connecting groove 57 and air-filled area on the non-air-filled area side are connected. The connecting block 58 and connecting groove 57 on one side have the same structure. The connecting block 58 has a top groove 581 inside, and a top block 584 is movably disposed in the top groove 581. Movable grooves 582 are respectively opened on the upper and lower sides of the top groove 581, and locking blocks 583 are movably disposed in the movable grooves 582. One end of the locking block 583 extends into the top groove 581, and the other end of the locking block 583 extends out of the outer surface of the connecting block 58. Both ends of the locking block 583 are rounded. The top block 584 has an inclined surface corresponding to the position of the locking block 583 to facilitate the ejection of the locking block 583. A screw 5 passes through the middle of the top block 584. 85. The screw 585 is threadedly connected to the top block 584. Both ends of the screw 585 are connected to the connecting block 58 via bearings. The screw 585 is driven by an external drive structure. The connecting groove 57 has a slot corresponding to the position of the locking block 583. Both the extension block 59 and the push plate 51 are provided with external drive structures. The external drive mechanism includes a transmission groove 586, a worm gear 587, a worm 588, and an internal hexagonal socket 589. The screw 585 corresponding to the extension block 59 extends into the extension block 59 and the worm gear 587 is fixedly installed. The extension block 59 has a transmission groove corresponding to the position of the worm gear 587. The moving groove 586 and the transmission groove 586 are also provided with a worm 588 that meshes with the worm wheel 587. One end of the worm 588 extends to the outer surface of the extension block 59 and is fixedly installed with an internal hexagon 589 that is easy to rotate. The screw 585 corresponding to the push plate 51 extends into the push plate 51 and is fixedly installed with the worm wheel 587. The push plate 51 has a transmission groove 586 in the position corresponding to the worm wheel 587. The transmission groove 586 is also provided with a worm 588 that meshes with the worm wheel 587. One end of the worm 588 extends to the outer surface of the push plate 51 and is fixedly installed with an internal hexagon 589 that is easy to rotate.

[0063] Example 3

[0064] like Figures 4-6 As shown, a tunneling method for a TBM capable of off-center loading includes the following steps:

[0065] Step S1: The TBM advances to the intersection of the first tunnel route and the second tunnel route;

[0066] Step S2: Excavate 25m along the route of the first tunnel;

[0067] Step S3: Retreat 25m to the intersection of the first tunnel route and the second tunnel route;

[0068] Step S4: Excavate 15m along the second tunnel route with eccentric loading;

[0069] Step S5: Continue excavating along the second tunnel for 35m;

[0070] Step S6: Retreat 50m to the intersection of the first tunnel route and the second tunnel route;

[0071] Step S7: Push along the first tunnel for 25m without air;

[0072] Step S8: Commence construction of the second tunnel.

[0073] The specific steps of the TBM rollback process are as follows:

[0074] a. The front shield 2 stabilizer extends to support the tunnel wall;

[0075] b. The hydraulic cylinder 3 extends to push the support shield 4 and the matching rearward movement by 1 stroke;

[0076] c. The front stabilizer is retracted, and the support boot 5 of the support shield 4 extends out of the support hole wall;

[0077] d. Rotate the cutter head 1 to push the hydraulic cylinder 3 for recovery;

[0078] e. The cutter head 1 and the front shield 2 move backward by 1 stroke;

[0079] f. If the support boot 5 has a support point, repeat a to e; if the support boot 5 has no support point, by adding an extension block 59 between the push plate 51 and the boot block 52 on one side of the airspace, the hydraulic cylinder is finely adjusted to push the support plate 54 to support the tunnel wall, thereby achieving the reaction force support of the support shield 4, repeat a to e.

[0080] g. Return to the specified position.

[0081] The specific steps for off-center tunneling of a TBM are as follows:

[0082] a. Twist the internal hexagon 589 on the push plate 51 on one side of the air zone to drive the worm gear 587 and worm 588.

[0083] b. When the screw 585 rotates, the top block 584 moves in the top groove 581, the locking block 583 loosens and disengages from the groove, the retracting support cylinder 56, and the connecting block 58 on the push plate 51 separates from the connecting groove 57 on the shoe block 52.

[0084] c. An extension block 59 is added between the push plate 51 and the shoe block 52. The connecting block 58 on the extension block 59 is inserted into the connecting groove 57 on the shoe block 52, and the connecting block 58 on the push plate 51 is inserted into the connecting groove 57 on the extension block 59. By turning the corresponding internal hexagon 589, the screw 585 is driven to rotate, and the top block 584 moves along the screw 585 to push out the locking block 583 into the slot using its inclined surface, thus completing the locking of the connecting block 58 and the connecting groove 57 and realizing the installation of the extension block 59.

[0085] d. Select the number of extension blocks 59 to be installed according to the conditions of the airspace, and adjust the hydraulic cylinder 53 to extend the support plate 54 on the tunnel wall to achieve reaction force support;

[0086] e. The cutterhead 1 rotates, and the propulsion cylinder 3 pushes the front shield 2 and the cutterhead 1 forward to achieve off-center tunneling;

[0087] f. After the eccentric tunneling is completed, turn the internal hexagon 589 and remove the added extension block 59.

[0088] The cutter head 1, front shield 2, propulsion cylinder 3, support shield 4, fine-tuning cylinder 53 and support cylinder 56 are all general standard parts or components known to those skilled in the art. Their structure and principle can be learned by those skilled in the art through technical manuals or conventional experimental methods, so they will not be described in detail here.

[0089] The foregoing has shown and described the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are only illustrative of the principles of the present invention. Various changes and modifications can be made to the present invention without departing from the spirit and scope of the present invention, and all such changes and modifications fall within the scope of the present invention as claimed.

Claims

1. A TBM capable of off-center tunneling, comprising a support shield (4), the front end of which is connected to a front shield (2) via a propulsion cylinder (3), a cutterhead (1) is provided at the front end of the front shield (2), a stabilizer is provided on the upper part of the front shield (2), and windows (6) are respectively provided on both sides of the support shield (4), with support shoes (5) provided in the windows (6); characterized in that: The support shoe (5) includes a support cylinder (56), a push plate (51), a shoe block (52), and a reaction force auxiliary fixture. The support cylinder (56) is fixedly installed inside the support shield (4). The support cylinder (56) is a bidirectional cylinder. Push plates (51) are fixedly installed at the left and right ends of the support cylinder (56), respectively. A shoe block (52) is set on the side of the push plate (51) away from the support cylinder (56). The reaction force auxiliary fixture includes a fine-tuning cylinder (53), a support plate (54), and a positioning device. A fine-tuning cylinder (53) is fixedly installed on the side of the shoe block (52) away from the support cylinder (56). The fine-tuning cylinders (53) are distributed in a matrix on the shoe block (52). The end of the fine-tuning cylinder (53) away from the shoe block (52) is connected to a support plate (54) through a ball joint. A positioning rod (55) is fixedly installed between the support plate (54) and the shoe block (52) to support the support plate (54) so ​​that its outer surface is flush with the outer surface of the support shield (4).

2. The TBM capable of off-center loading tunneling according to claim 1, characterized in that: The support shoe (5) is divided into a non-airborne area side and an airborne area side on both sides relative to the support cylinder (56), and the structures on both sides are respectively: On the non-air zone side: A connecting block (58) is fixedly installed on the side of the push plate (51) away from the support cylinder (56), and a connecting groove (57) is opened on the side of the shoe block (52) near the support cylinder (56). The connecting block (58) on the push plate (51) and the connecting groove (57) on the shoe block (52) are connected in cooperation. On the side of the air-filled area: The reaction force auxiliary tooling also includes an extension block (59) disposed between the push plate (51) and the shoe block (52). The extension block (59) has a connecting groove (57) on the side near the push plate (51). The extension block (59) has a connecting block (58) fixedly installed on the side away from the push plate (51). The shoe block (52) has a connecting groove (57) with the same as the connecting groove (57) on the extension block (59) on the side near the extension block (59). The push plate (51) has a connecting block (58) with the same as the connecting block (58) on the extension block (59) fixedly installed on the side away from the support cylinder (56).

3. A TBM capable of off-center loading tunneling according to claim 2, characterized in that: When there is one extension block (59) on one side of the air-filled area, the connecting block (58) on the push plate (51) is connected to the connecting groove (57) on the extension block (59), and the connecting block (58) on the extension block (59) is connected to the connecting groove (57); when there are at least two extension blocks (59), the connecting block (58) on the push plate (51) is connected to the connecting groove (57) on the extension block (59), the connecting blocks (58) and connecting grooves (57) on two adjacent extension blocks (59) are connected to each other, and the connecting block (58) on the extension block (59) is connected to the connecting groove (57).

4. A TBM capable of off-center loading tunneling according to claim 3, characterized in that: The connecting block (58) and connecting groove (57) on the non-air zone side and the connecting block (58) and connecting groove (57) on the air zone side have the same structure. The connecting block (58) has a top groove (581) inside. A top block (584) is movably arranged in the top groove (581). Movable grooves (582) are respectively opened on the upper and lower sides of the top groove (581). A locking block (583) is movably arranged in the movable groove (582). One end of the locking block (583) extends into the top groove (581), and the other end of the locking block (583) extends out of the connecting block. On the outer surface of the block (58), both ends of the locking block (583) are rounded. The top block (584) has an inclined surface corresponding to the position of the locking block (583) to facilitate the ejection of the locking block (583). A screw (585) is threaded through the middle of the top block (584). The screw (585) is threaded to the top block (584). Both ends of the screw (585) are connected to the connecting block (58) through bearings. The screw (585) is driven by an external drive structure. The connecting groove (57) has a slot corresponding to the position of the locking block (583).

5. A TBM capable of off-center loading tunneling according to claim 4, characterized in that: Both the extension block (59) and the push plate (51) are provided with external drive structures, which include a transmission groove (586), a worm gear (587), a worm (588), and an internal hexagonal screw (589). A screw (585) corresponding to the extension block (59) extends into the extension block (59) and a worm gear (587) is fixedly installed therein. The extension block (59) has a transmission groove (586) corresponding to the position of the worm gear (587) inside. A worm (588) meshing with the worm gear (587) is also provided in the transmission groove (586). 88) One end extends to the outer surface of the extension block (59) and is fixedly installed with an internal hexagon (589) for easy rotation; the screw (585) corresponding to the push plate (51) extends to the push plate (51) and is fixedly installed with a worm gear (587). The push plate (51) has a transmission groove (586) corresponding to the position of the worm gear (587) inside. The transmission groove (586) is also provided with a worm (588) that meshes with the worm gear (587). One end of the worm (588) extends to the outer surface of the push plate (51) and is fixedly installed with an internal hexagon (589) for easy rotation.

6. A tunneling method using a TBM capable of off-center loading as described in claim 5, characterized in that: Includes the following steps: Step S1: The TBM advances to the intersection of the first tunnel route and the second tunnel route; Step S2: Excavate 25m along the route of the first tunnel; Step S3: Retreat 25m to the intersection of the first tunnel route and the second tunnel route; Step S4: Excavate 15m along the second tunnel route with eccentric loading; Step S5: Continue excavating along the second tunnel for 35m; Step S6: Retreat 50m to the intersection of the first tunnel route and the second tunnel route; Step S7: Push along the first tunnel for 25m without air; Step S8: Proceed with the construction of the second tunnel.

7. The tunneling method according to claim 6, characterized in that: The specific steps of the TBM rollback process are as follows: a. The front shield (2) stabilizer extends out to support the tunnel wall; b. The hydraulic cylinder (3) extends to push the support shield (4) and then moves backward by one stroke; c. The front stabilizer is retracted, and the support boot (5) of the support shield (4) extends out of the support hole wall; d. Rotate the cutter head (1) and push the hydraulic cylinder (3) to recover; e. The cutter head (1) and the front shield (2) move back one stroke; f. If the support boot (5) has a support point, repeat a to e; if the support boot (5) has no support point, by adding an extension block (59) between the push plate (51) and the boot block (52) on one side of the airspace, the hydraulic cylinder is finely adjusted to push the support plate (54) to support on the tunnel wall, thereby achieving the reaction force support of the support shield (4), repeat a to e; g. Return to the specified position.

8. The tunneling method according to claim 6, characterized in that: The specific steps for off-center tunneling of a TBM are as follows: a. Turn the internal hexagon (589) on the push plate (51) on one side of the air zone to drive the worm gear (587) and worm (588); b. When the screw (585) rotates, the top block (584) moves in the top groove (581), the locking block (583) loosens and disengages from the locking groove, the support cylinder (56) retracts, and the connecting block (58) on the push plate (51) separates from the connecting groove (57) on the shoe block (52). c. An extension block (59) is added between the push plate (51) and the shoe block (52). The connecting block (58) on the extension block (59) is inserted into the connecting groove (57) on the shoe block (52). The connecting block (58) on the push plate (51) is inserted into the connecting groove (57) on the extension block (59). By turning the corresponding internal hexagon (589), the screw (585) is driven to rotate. The top block (584) moves along the screw (585) and uses its inclined surface to push out the card block (583) into the card slot, thus completing the locking of the connecting block (58) and the connecting groove (57) and realizing the installation of the extension block (59). d. Select the number of extension blocks (59) to be installed according to the conditions of the airspace, and adjust the oil cylinder (53) to extend the support plate (54) on the tunnel wall to achieve reaction force support; e. The cutterhead (1) rotates, and the propulsion cylinder (3) pushes the front shield (2) and the cutterhead (1) forward to achieve off-center tunneling; f. After the off-center excavation is completed, turn the internal hexagon (589) and remove the added extension block (59).

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