An open type TBM for tunnel enlargement and a tunnel enlargement method

Abstract

An open type TBM for tunnel expansion is used for performing expansion work of an original tunnel with a cross section of a gate shape, a front shield guard plate and a middle shield guard plate are arranged between a front shield and a middle shield of the open type TBM, a front part of the front shield guard plate is fixedly connected with a rear part of the front shield, the front shield guard plate is located outside the middle shield guard plate, a rear part of the front shield guard plate partially overlaps with a front part of the middle shield guard plate, and a rear part of the middle shield guard plate is fixedly connected with a front part of the middle shield. The design can avoid that slag is exposed to the rear of the TBM main machine, and under the joint action of water flow and mechanical disturbance in the tunnel, the slag falls to the bottom area of the tunnel and is accumulated, thereby affecting the continuous tunneling of the TBM.

Description

Technical Field

[0001] This invention relates to the field of tunnel construction technology, and specifically to an open-type TBM and a tunnel widening method for tunnel widening. Background Technology

[0002] Traditional mine tunnel construction largely relies on the drill-and-blast method. However, this method has significant drawbacks, including low construction efficiency, difficulty in ensuring safety, and considerable damage to the surrounding environment. Therefore, an increasing number of projects are opting for single-shield TBMs (tunnel boring machines), double-shield TBMs, and open-face TBMs. In certain specific areas, regulations even mandate the use of TBMs for tunnel construction. From a construction perspective, for some projects that utilize TBMs from the outset, tunnels can be formed in a single operation, eliminating the need for enlargement work or special paving devices. However, some projects still require TBM enlargement work on top of existing drill-and-blast tunnels that form a tunnel arch shape.

[0003] In scenarios involving the widening of arch-shaped tunnels created using the traditional drill-and-blast method, numerous pressing problems arise during actual construction. For instance, during TBM widening operations, when the TBM's circular cutterhead is cutting, some of the excavated material follows the normal workflow, being scooped up by the cutterhead bucket and transported out of the tunnel via the internal chute into the belt conveyor system. However, another portion of the excavated material is compressed into two triangular areas on either side of the bottom of the original arch-shaped tunnel. As the TBM moves forward, this excavated material gradually becomes exposed behind it. Under the combined effects of water flow and mechanical disturbance within the tunnel, the material slides down to the bottom of the tunnel and accumulates, severely impacting the continuous excavation of the TBM. In practice, the machine must be stopped, and a large amount of manpower must be deployed to clear this accumulated material. This results in the TBM operating intermittently, significantly reducing construction efficiency.

[0004] Meanwhile, the wheels of the TBM's rear trolley are arranged on both sides of the bottom. When the TBM is in normal full-face tunneling condition, the wheels can just contact the excavated tunnel wall and roll on the tunnel wall, thus ensuring the stability and normal movement of the trolley. However, when facing the widening excavation condition, due to the influence of the original arch-shaped tunnel face, the wheels may not be able to contact the tunnel wall. In this case, the trolley's posture is difficult to control effectively, which has an adverse effect on the overall construction progress and safety. Summary of the Invention

[0005] The purpose of this invention is to overcome the problems existing in the prior art where, during the widening and excavation of arch-shaped tunnels, the slag is squeezed and piled up in two triangular areas on both sides of the bottom of the original arch-shaped tunnel, affecting the continuous excavation of the TBM. At the same time, under the influence of the original arch-shaped tunnel, the original traveling wheels of the TBM's rear trolley cannot contact the tunnel wall, making it difficult to control the trolley's posture. This invention provides an open-type TBM and widening method that can avoid the impact of slag on the continuous excavation of the TBM during tunnel widening and excavation.

[0006] To achieve the above objectives, the technical solution of the present invention is:

[0007] An open-face TBM for tunnel widening is provided. The open-face TBM is used to widen existing tunnels with an arch-shaped cross-section. A front shield plate and a middle shield plate are provided between the front shield and the middle shield of the open-face TBM. The front part of the front shield plate is fixedly connected to the rear part of the front shield. The front shield plate is located outside the middle shield plate. The rear part of the front shield plate partially overlaps with the front part of the middle shield plate. The rear part of the middle shield plate is fixedly connected to the front part of the middle shield.

[0008] The front shield plate is an arc-shaped plate with the central axis of the front shield as the center of rotation. There are two front shield plates, which are symmetrically arranged on both sides of the bottom of the TBM.

[0009] The central shield plate is an arc-shaped plate with the central axis of the central shield as the center of rotation. There are two central shield plates, which are symmetrically arranged on both sides of the bottom of the TBM.

[0010] When carrying out the widening operation, a circle is drawn with the excavation axis of the tunnel design as the center and the excavation radius of the TBM cutterhead as the radius to obtain a circular widening section. The two areas on both sides of the bottom of the original arch-shaped tunnel section that do not coincide with the circular widening section are called area C. The two fan-shaped areas corresponding to area C on the circular widening section are called area A.

[0011] The central angles of the two front shield plates on the circular excavation section cover the central angles α of the two A regions on the circular excavation section;

[0012] The central angles of the two shield plates on the circular excavation section cover the central angles α of the two A regions on the circular excavation section.

[0013] The gaps formed between the two front shield plates and between the two middle shield plates are drainage areas, and a pumping device is installed in the drainage areas.

[0014] The open-type TBM's rear support trolley is equipped with at least one pair of inclined wheels and at least one pair of sliding shoes. Each pair of inclined wheels is symmetrically arranged at the bottom of the rear support trolley, and the sliding shoes are arranged inside the inclined wheels.

[0015] The inclined wheel is set at an angle and has a protruding arc tread surface. The arc tread surface is matched with the circular excavation section obtained with the excavation axis of the tunnel design as the center and the excavation radius of the cutterhead.

[0016] The slipper is a boat-shaped structure that extends obliquely upward at both ends. The slipper is inclined and the bottom surface of the slipper is arc-shaped. The bottom surface of the slipper matches the inner surface of the excavation trench formed by the cutterhead of the TBM at the bottom of the arch-shaped original tunnel.

[0017] The bottom of the rear trolley of the open-type TBM is equipped with two pairs of inclined wheels and two pairs of slip shoes.

[0018] The middle part of the skate is fixedly connected to the bottom of the skate bracket, the top of the skate bracket is rotatably engaged with the bottom of the connecting bracket through a connecting pin, and the top of the connecting bracket is fixedly connected to the bottom of the rear matching trolley.

[0019] A tunnel widening method, the widening method being based on the above-mentioned open-face TBM for tunnel widening, comprising:

[0020] Based on the existing tunnel with an arch-shaped cross-section, the diameter of the open-face TBM used for widening is selected. An open-face TBM with a widening diameter larger than the width of the existing tunnel is selected, and the widening excavation face is determined so that the widening excavation face covers a part of the area below the ground of the existing tunnel.

[0021] Based on the excavation face to be excavated, the selected open-face TBM is used to carry out the excavation operation.

[0022] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0023] 1. In an open-face TBM for tunnel widening, the present invention provides a front shield plate and a middle shield plate between the front shield and the middle shield. The front part of the front shield plate is connected to the front shield, and the front shield plate is located outside the middle shield plate. The rear part of the front shield plate partially overlaps with the front part of the middle shield plate, and the rear part of the middle shield plate is connected to the middle shield, i.e., to tighten the shield. During the widening excavation, the front shield plate and the middle shield plate can effectively shield the excavated material, significantly reducing the amount of excavated material entering the area between the front and middle shields, reducing the amount of excavated material removal work, and ensuring the continuity of TBM tunneling. Therefore, the present invention provides a shield plate between the front and middle shields of the open-face TBM to shield the excavated material, significantly reducing the amount of excavated material entering the area between the front and middle shields, reducing the amount of excavated material removal work, ensuring the continuity of TBM tunneling, and thus improving mining efficiency.

[0024] 2. In an open-type TBM for tunnel widening according to the present invention, two front shield plates are symmetrically arranged on both sides of the bottom of the TBM. The lower edge of each front shield plate overlaps with the widening section of the TBM cutterhead at the bottom of the arch-shaped original tunnel, and the upper edge of the front shield plate overlaps with the excavation section of the TBM cutterhead at the side of the arch-shaped original tunnel. Simultaneously, two middle shield plates are symmetrically arranged on both sides of the bottom of the TBM. The lower edge of each middle shield plate overlaps with the widening section of the TBM cutterhead at the bottom of the arch-shaped original tunnel, and the upper edge of the middle shield plate overlaps with the excavation section of the TBM cutterhead at the side of the arch-shaped original tunnel. The two front shield plates and the two middle shield plates... The space between the tunnel sections serves as a drainage area, equipped with a pumping device. During tunneling operations, the front and middle shield plates block the slag material accumulating on both sides of the bottom of the original arch-shaped tunnel, minimizing its entry into the drainage area. Simultaneously, gaps exist between the front and middle shield plates, allowing seepage water to flow downwards under gravity into the lowest point of the tunnel boring machine's bottom drainage area. This seepage does not affect the equipment's tunneling progress and can be discharged via a drainage pump. Furthermore, after the seepage mud and water are pumped away from the shield plate area using a mud pump (drainage pump), the remaining mud and sand, lacking moisture, are less likely to disperse and can be fixed in triangular areas on both sides of the tunnel, minimizing interference with the subsequent track movement. Therefore, in this invention, the front shield plate and the middle shield plate block the slag, so that very little slag enters the drainage area, while allowing seepage water to flow downward into the drainage area. The seepage water in the drainage area can be easily discharged by the drainage pump without affecting the tunneling operation. At the same time, the remaining mud and sand, due to the lack of moisture, are not easy to disperse and can be shaped into triangular areas on both sides of the tunnel, without interfering with the movement of the subsequent supporting track.

[0025] 3. In this invention, an open-type TBM for tunnel widening is equipped with two sets of four sliding shoes (front and rear) and two sets of four inclined wheels (front and rear). The sliding shoes and the traveling wheels function differently under different working conditions. In the full-section excavation section, the tunneling machine directly excavates a circular cross-section without an existing tunnel. At this time, the inclined wheels can touch the circular tunnel wall formed by the tunneling machine, providing support for movement. In the widening excavation condition, due to the triangular area formed on both sides of the bottom of the original arched tunnel, the inclined wheels cannot contact the tunnel wall. At this time, the sliding shoes located on the inner side of the inclined wheels contact the inner wall of the widening trench formed by the tunneling machine cutterhead at the middle position of the bottom of the original arched tunnel. Driven by the traveling force of the tunneling machine, the sliding shoes slide in the widening trench. At this time, the sliding shoes replace the inclined wheels to provide support and load-bearing function. The cooperation between the sliding shoes and the inclined wheels allows the rear-mounted trolley to adapt to different working conditions without the need for a track. Therefore, in this invention, each rear-mounted trolley is equipped with inclined wheels and sliding shoes. The sliding shoes and inclined wheels work together to enable the rear-mounted trolley to adapt to different working conditions, and there is no need to set up a track. Attached Figure Description

[0026] Figure 1 This is a structural diagram of an open-type TBM.

[0027] Figure 2 This is a schematic diagram showing the positional relationship between the front shield plate and the middle shield plate.

[0028] Figure 3 This is a schematic diagram of an open-type TBM under widening excavation conditions.

[0029] Figure 4 This is a side view of the supporting trolley.

[0030] Figure 5 This is a schematic diagram of the movement of the supporting trolley during widening excavation.

[0031] Figure 6 This is a schematic diagram showing the movement of the supporting trolley after it enters the full-section excavation section.

[0032] Figure 7 This is a side view of the skates.

[0033] Figure 8 This is a front view diagram of the skates.

[0034] Figure 9 This is a schematic diagram of the skate boot's structure.

[0035] Figure 10 This is a schematic diagram of the original tunnel cross-section and the excavation construction cross-section.

[0036] In the diagram: front shield 1, middle shield 2, front shield guard plate 3, middle shield guard plate 4, rear matching trolley 5, inclined wheel 6, sliding shoe 7, connecting bracket 71, connecting pin 72, sliding shoe bracket 73. Detailed Implementation

[0037] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0038] For tunnel construction operations, to ensure schedule and safety, it may be necessary to perform TBM widening excavation on the basis of the existing drill-and-blast tunnel (tunnel portal type). Figure 10 As shown, a small-diameter widening excavation is being carried out on the basis of the original arch-shaped tunnel. Due to project requirements, the circular widening section formed by the widening cannot completely cover the original arch-shaped tunnel section. On the interface of the original arch-shaped tunnel, there are two triangular areas on both sides of the bottom that do not coincide with the circular widening section. During the widening process, part of the slag cut by the cutterhead is scooped up by the cutterhead bucket according to the normal working procedure and enters the belt conveyor system through the slag chute inside the cutterhead to be transported out of the tunnel; the other part of the slag is squeezed into the two triangular areas on both sides of the bottom of the original arch-shaped tunnel that do not coincide with the circular widening section. This part of the slag will enter between the front shield 1 and the middle shield 2 of the TBM (in this embodiment, the shield is a supporting shield, and the supporting shield is equipped with a support shoe for supporting the rock wall to achieve fixation), and it is easy to slide down to the bottom area of ​​the tunnel and accumulate, which is difficult to clean and easily mixes with tunnel seepage water. It is often necessary to stop the machine to remove this part of the slag, which affects the construction efficiency.

[0039] like Figure 1 As shown, an open-face TBM is used for widening existing tunnels with an arch-shaped cross-section. The existing tunnel can be a hydraulic tunnel with a turning radius of R500 meters or more. A front shield plate 3 and a middle shield plate 4 are provided between the front shield 1 and the middle shield 2 of the open-face TBM. The front part of the front shield plate 3 is fixedly connected to the rear part of the front shield 1. Figure 2 As shown, the front shield plate 3 is arranged on the outside of the middle shield plate 4 along the radial direction of the TBM. The rear part of the front shield plate 3 partially overlaps with the front part of the middle shield plate 4, and the rear part of the middle shield plate 4 is fixedly connected to the front part of the middle shield 2.

[0040] Because front shield plate 3 and middle shield plate 4 are installed between front shield 1 and middle shield 2, front shield plate 3 and middle shield plate 4 are used to block the slag in the triangular area on both sides of the bottom of the original arch-shaped tunnel, which greatly reduces the amount of slag entering the area between front shield 1 and middle shield 2, reduces the amount of slag removal work, ensures the continuity of TBM tunneling, and improves work efficiency.

[0041] The front shield plate 3 is an arc-shaped shield plate with the central axis of the front shield 1 as the center of rotation. There are two front shield plates 3, which are symmetrically arranged on both sides of the bottom of the TBM. The middle shield plate 4 is an arc-shaped shield plate with the central axis of the middle shield 2 as the center of rotation. There are two middle shield plates 4, which are symmetrically arranged on both sides of the bottom of the TBM.

[0042] In some widening operations, for example when the radius of the circular widening excavation face is smaller than the distance from the center of the original arch-shaped tunnel to the bottom edge of the tunnel, there exists a triangular area on each side of the bottom of the original arch-shaped tunnel that does not coincide with the circular widening excavation face, i.e., an attached... Figure 3 The two C zones contain slag accumulation. These two C zones correspond to two fan-shaped areas on the circular widened section, i.e., attached... Figure 3 In the circular excavation face, the fan-shaped area between two areas A is denoted as area B, such as... Figure 3 As shown, protective plates are only installed in area A, including a front shield plate 3 and a middle shield plate 4. Area B does not have front shield plates 3 and middle shield plates 4, leaving space at the bottom of area B for water seepage control. Furthermore, to better prevent slag buildup, the front shield plate 3 is designed as an arc-shaped plate with the central axis of the front shield 1 as its rotation center, and the middle shield plate 4 is designed as an arc-shaped plate with the central axis of the middle shield 2 as its rotation center. Both the front shield plate 3 and the middle shield plate 4 are positioned near the outer edge of area A.

[0043] To ensure that the front shield plate 3 and the middle shield plate 4 can cooperate with each other and prevent the triangular areas on both sides of the bottom of the original arch-shaped tunnel from sliding to the bottom of the tunnel, the central angles of the two front shield plates 3 on the circular widening section cover the central angles of the two areas A on the circular widening section.

[0044] To achieve better slag blocking effect, the size and angle of the front shield plate 3 and the middle shield plate 4 need to be selected according to the actual construction conditions. In this invention, the central angle of the front shield plate 3 on the circular excavation surface needs to be greater than the central angle α of area A on the circular excavation surface. That is, when performing the excavation operation, the lower edge of each of the front shield plates 3 overlaps with the excavation groove formed by the TBM cutterhead at the bottom of the arch-shaped original tunnel, and the upper edge of each front shield plate 3 overlaps with the excavation groove formed by the TBM cutterhead at the side of the arch-shaped original tunnel.

[0045] Similarly, the central angle of the middle shield plate 4 on the circular excavation surface needs to cover the central angle α of area A on the circular excavation surface. That is, during the excavation operation, the lower edge of each of the middle shield plates 4 overlaps with the excavation groove formed by the TBM cutterhead at the bottom of the arch-shaped original tunnel, and the upper edge of each middle shield plate 4 overlaps with the excavation groove formed by the TBM cutterhead at the side of the arch-shaped original tunnel. The central angles of the front shield plate 3 and the middle shield plate 4 on the circular excavation surface are larger than the central angle α corresponding to area A in the figure. Furthermore, the front shield plate 3 is set closer to the outer edge of the front shield 1, and the middle shield plate 4 is set closer to the outer edge of the middle shield 2, so that all the slag in this area can be tightly blocked in the triangular areas on both sides of the bottom of the tunnel.

[0046] The installation of the front shield plate 3 and the middle shield plate 4 prevents the slag material located in area C from entering area B. The slag material accumulated in area C on both sides of the bottom of the original arch-shaped tunnel is relatively loose. There is a gap between the front shield plate 3 and the middle shield plate 4. The front shield plate 3 and the middle shield plate 4 do not affect the downward flow of seepage water to the gap formed between the two front shield plates 3 and the two middle shield plates 4 at the bottom of the tunnel.

[0047] The gap formed between the two front shield plates 3 and the two middle shield plates 4 (i.e., the bottom position of area B) is a drainage area. At the same time, since there is a certain space left in the drainage area, a water pump or other pumping equipment for removing seepage can be installed here.

[0048] This invention utilizes the front shield plate 3, the middle shield plate 4, and the drainage area to filter and collect seepage water within the shield plate area for drainage. This arrangement at the front of the shield achieves separation of seepage water and silt. After the silt is pumped out from the shield plate area using a slurry pump, the remaining silt, lacking moisture, is less likely to disperse and can be contained in triangular areas on both sides of the tunnel. This prevents large amounts of seepage water carrying silt from rushing to the rear from the triangular area during widening excavation, burying the supporting track, affecting equipment movement, and causing equipment failure.

[0049] In an open-type TBM construction system, the rear-mounted auxiliary trolley is constantly driven forward by the TBM main unit. The movement mode of the auxiliary trolley is set according to the tunnel diameter, slope, and surrounding rock conditions. In this embodiment, a trackless trolley is used, and the bottom of the trolley is equipped with curved inclined wheels and slippers to adapt to two different working conditions: tunnel widening in the drill-and-blast section and full-face excavation.

[0050] Specifically, such as Figure 4As shown, the rear support trolley 5 of the open TBM is equipped with at least one pair of inclined wheels 6 and at least one pair of sliding shoes 7. Each pair of inclined wheels 6 is symmetrically arranged on the bottom of the rear support trolley 5, and the sliding shoes 7 are arranged on the inner side of the inclined wheels 6. Each pair of sliding shoes 7 is symmetrically arranged on the bottom of the rear support trolley 5.

[0051] In this invention, the rear-mounted trolley 5 is equipped with a traveling mechanism consisting of inclined wheels 6 and sliding shoes 7. The inclined wheels 6 are designed for full-face rock excavation. The outer circumference of the inclined wheel 6 is machined to R = the excavation radius of the cutterhead, giving it a convex arc tread surface. This arc tread surface mates with the circular excavation cross-section obtained with the tunnel design excavation axis as the center and the excavation radius of the cutterhead. Simultaneously, the axle of the inclined wheel 6 forms a certain angle with the vertical line (i.e., the inclined wheel inclination angle) to facilitate positioning and stable movement on the circular excavation cross-section. The inclined wheel 6 is hinged to the bottom support of the rear-mounted trolley to achieve small-amplitude oscillation, ensuring constant contact with the arc of the excavation cross-section. Figure 6 As shown, when the TBM widening section is completed and full-face rock excavation is required, the excavated section is a complete circle. At this time, the inclined wheel 6 can just contact the excavated rock wall and roll on the tunnel wall to provide support. At this time, the rear trolley 5 does not need to be equipped with the skid shoe 7.

[0052] During the widening and excavation operation, Figure 5 As shown, Figure 5 The diagram illustrates the movement of the rear-mounted trolley during widening excavation. Because the trolley has a certain width, and to maintain stability, the inclined wheels 6 are generally located on both sides of the trolley. Therefore, the inclined wheels 6 are positioned on both sides of the bottom of the circular widening excavation face formed by the cutterhead, as shown in the diagram. Figure 3 Within area A shown, the bottom of area A is the rock debris accumulation zone. Because the debris is soft and shapeless, and does not completely fill the corners of the original tunnel bottom, a regular and complete bearing surface cannot be formed on the rock debris surface. At this time, the outer ring of the inclined wheel 6 cannot contact the tunnel wall, and most of the time it does not contact the rock debris. Relying solely on the inclined wheel 6 for movement would lead to an inability to control the attitude of the rear-mounted trolley 5, affecting its movement. Therefore, a sliding shoe 7 is installed on the inner side of the inclined wheel 6. This sliding shoe structure is specifically designed for widening excavation sections. Under widening excavation conditions, the sliding shoe 7 supports the rear-mounted trolley 5 and enables its normal movement.

[0053] Specifically, such as Figure 4 , Figure 5As shown, the open-type TBM's rear-mounted trolley 5 has a pair of inclined wheels 6 at both the front and rear. Four sets of sliding shoes 7 are positioned between these two pairs of wheels, arranged in two rows at the bottom of the trolley 5. The sliding shoes 7 are tilted to facilitate positioning and movement directly on the circular excavation surface. During widening operations, because the sliding shoes 7 are located inside the inclined wheels 6 and in area B of the circular widening excavation surface, the front shield plate 3 and the middle shield plate 4 prevent debris from entering area B. The bottom of area B is a widening trench excavated by the TBM cutterhead, which contains a solid rock surface with good load-bearing support. During widening operations, the bottom of the sliding shoes 7 contacts the inside of the widening trench and slides within it under the drive of the main unit. The sliding shoes move more smoothly and reliably on this type of surface, without significant undulations. Therefore, the sliding shoe setting can keep the trolley from deviating from the design position on the widened section, without affecting the normal connection of equipment and pipelines in the trolley workshop, and allow the trolley to slide effectively on the tunnel section of the widened section, so as to ensure the normal operation of the equipment carried by the matching trolley 5.

[0054] like Figures 7 to 9 As shown, the sliding shoe 7 is a boat-shaped structure that extends obliquely upwards at both ends to prevent it from getting stuck when encountering obstacles during its movement. The sliding shoe 7 is set at an angle and its bottom surface is an arc surface. When performing widening excavation operations, the bottom surface of the sliding shoe 7 is located on a cylindrical surface with the excavation axis of the tunnel design as the center and the excavation radius of the cutterhead as the radius. The bottom surface of the sliding shoe 7 matches the inner surface of the widening trench formed by the TBM cutterhead in the arch-shaped widening excavation of the original tunnel bottom, so that it can move better on the arc-shaped excavation cross section.

[0055] The middle part of the slipper 7 is fixedly connected to the bottom of the slipper bracket 73. The top of the slipper bracket 73 is rotatably engaged with the bottom of the connecting bracket 71 via a connecting pin 72. The top of the connecting bracket 71 is fixedly connected to the bottom of the rear supporting trolley 5. During the widening operation, the central axis of the connecting pin 72 is located on the tangent of the circular widening section formed by the cutterhead's widening operation, and the angle between the inclination angle of the central axis of the connecting pin 72 and the inclination angle of the slipper 7 is 90 degrees. The slipper 7 and the slipper bracket 73 swing in the direction of travel of the rear supporting trolley 5 through the connecting pin 72 to ensure that the slipper 7 cooperates with the surrounding rock. Through the cooperation of the inclined wheel 6 and the slipper 7, the rear supporting trolley 5 can adapt to different working conditions of widening section construction and full-face tunneling.

[0056] A tunnel widening method, based on the aforementioned open-face TBM for tunnel widening, the tunnel widening method comprising:

[0057] Based on the existing tunnel with an arch-shaped cross-section, the diameter of the open-face TBM to be used for excavation is selected. An open-face TBM with an excavation diameter larger than the width of the existing tunnel is selected, and the excavation face of the excavation is determined so that the excavation face of the excavation covers a part of the area below the ground of the existing tunnel.

[0058] Based on the excavation face to be excavated, the selected open-face TBM is used to carry out the excavation operation.

[0059] The principle of this invention is explained as follows:

[0060] The open-face TBM and excavation method used in this invention are mainly for the excavation of drill-and-blast tunnel sections. However, mining tunnels are generally arch-shaped, and before excavation, the excavation diameter of the tunnel boring machine (TBM) needs to be selected. Figure 10 As shown, the circular excavation section formed by the TBM tunneling machine is slightly larger than the existing arch-shaped section. At the same time, the bottom of the existing arch-shaped tunnel also needs to be excavated. Otherwise, the cylindrical TBM will not be able to obtain reliable support, and it will easily roll and its own posture will easily deviate.

[0061] Because the two triangular areas on both sides of the bottom of the original arch-shaped tunnel are prone to accumulating debris, the continuous tunneling of the TBM and the movement of the rear supporting trolley are affected. This invention solves the problem by setting a front shield plate 3 and a middle shield plate 4 between the front shield 1 and the middle shield 2 of the open TBM. The front shield plate 3 and the middle shield plate 4 are set on both sides of the bottom of the open TBM. The front shield plate 3 and the middle shield plate 4 prevent debris from entering the rear of the TBM and the bottom of the tunnel. The bottom of the tunnel forms a drainage area, which facilitates the removal of debris and the discharge of seepage water, and does not affect the movement of the rear supporting trolley 5.

[0062] Meanwhile, in order to adapt to the construction of the tunnel widening section, the present invention has designed the walking mechanism at the bottom of the rear supporting trolley 5. The bottom of the rear supporting trolley 5 is equipped with inclined wheels 6 and sliding shoes 7. The sliding shoe structure is designed specifically for the construction of the widening section. Under the widening condition, the sliding shoes 7 support the rear supporting trolley 5 and enable the rear supporting trolley 5 to move normally. The inclined wheels 6 are set for the full-face rock excavation condition. Under the full-face rock excavation condition, the inclined wheels 6 roll on the rock wall and support the rear supporting trolley 5.

[0063] Example 1:

[0064] An open-face TBM for tunnel widening is disclosed. The open-face TBM is used to widen existing tunnels with an arched cross-section. A front shield plate 3 and a middle shield plate 4 are provided between the front shield 1 and the middle shield 2 of the open-face TBM. The front part of the front shield plate 3 is fixedly connected to the rear part of the front shield 1. The front shield plate 3 is located outside the middle shield plate 4, and the rear part of the front shield plate 3 partially overlaps with the front part of the middle shield plate 4. The rear part of the middle shield plate 4 is fixedly connected to the front part of the middle shield 2. The front shield plate 3 is an arc-shaped plate with the central axis of the front shield 1 as its rotation center. There are two front shield plates 3, symmetrically arranged on both sides of the bottom of the TBM. The middle shield plate 4 is also an arc-shaped plate with the central axis of the middle shield 2 as its rotation center. There are two middle shield plates 4, symmetrically arranged on both sides of the bottom of the TBM. Symmetrically arranged on both sides of the bottom of the TBM; during the widening operation, a circle is drawn with the excavation axis of the tunnel design as the center and the excavation radius of the cutterhead as the radius, resulting in a circular widening section. The two areas on the bottom sides of the original arch-shaped tunnel section that do not coincide with the circular widening section are designated as two fan-shaped areas on the circular widening section, denoted as area A; the fan-shaped area between the two areas A on the circular widening section is designated as area B; the projection angles of the two front shield plates 3 on the circular widening section cover the projection angles of the two areas A on the circular widening section; the projection angles of the two middle shield plates 4 on the circular widening section cover the projection angles of the two areas A on the circular widening section; the gaps formed between the two front shield plates 3 and between the two middle shield plates 4 are drainage areas, and pumping devices are installed in the drainage areas.

[0065] Example 2:

[0066] Example 2 is basically the same as Example 1, except that:

[0067] The rear support trolley 5 of the open-type TBM is equipped with at least one pair of inclined wheels 6 and at least one pair of sliding shoes 7. Each pair of inclined wheels 6 is symmetrically arranged on the bottom of the rear support trolley 5, and the sliding shoes 7 are located on the inner side of the inclined wheels 6. The bottom of the rear support trolley 5 of the open-type TBM is equipped with two pairs of inclined wheels 6 and two pairs of sliding shoes 7. The inclined wheels 6 are inclined and have a convex arc-shaped tread surface. The arc-shaped tread surface is centered on the excavation axis of the tunnel design and oriented with respect to the cutterhead. The excavation radius is matched with the circular widening section; the slipper 7 is a boat-shaped structure that extends obliquely upward at both ends. The slipper 7 is inclined and the bottom surface of the slipper 7 is arc-shaped. The bottom surface of the slipper 7 matches the inner surface of the widening groove formed by the cutterhead of the TBM at the bottom of the arch-shaped original tunnel; the middle part of the slipper 7 is fixedly connected to the bottom of the slipper bracket 73. The top of the slipper bracket 73 is rotatably connected to the bottom of the connecting bracket 71 through the connecting pin 72. The top of the connecting bracket 71 is fixedly connected to the bottom of the rear matching trolley 5.

[0068] Example 3:

[0069] A tunnel widening method, said widening method being based on the open-face TBM used for tunnel widening as described in Embodiment 1 or 2, comprising:

[0070] Based on the existing tunnel with an arch-shaped cross-section, the diameter of the open-face TBM used for widening is selected. An open-face TBM with a widening diameter larger than the width of the existing tunnel is selected, and the widening excavation face is determined so that the widening excavation face covers a part of the area below the ground of the existing tunnel.

[0071] Based on the excavation face to be excavated, the selected open-face TBM is used to carry out the excavation operation.

[0072] The above description is only a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiments. Any equivalent modifications or changes made by those skilled in the art based on the content disclosed in the present invention should be included within the scope of protection set forth in the claims.

Claims

1. An open-type TBM for tunnel widening, characterized in that: The open-type TBM is used to perform the widening operation of the original tunnel with an arch-shaped cross section. A front shield plate (3) and a middle shield plate (4) are provided between the front shield (1) and the middle shield (2) of the open-type TBM. The front part of the front shield plate (3) is fixedly connected to the rear part of the front shield (1). The front shield plate (3) is located outside the middle shield plate (4). The rear part of the front shield plate (3) and the front part of the middle shield plate (4) partially overlap. The rear part of the middle shield plate (4) is fixedly connected to the front part of the middle shield (2). The front shield plate (3) is an arc-shaped shield plate with the central axis of the front shield (1) as the rotation center. There are two front shield plates (3), which are symmetrically arranged on both sides of the bottom of the TBM. The central shield plate (4) is an arc-shaped shield plate with the central axis of the central shield (2) as the rotation center. There are two central shield plates (4), which are symmetrically arranged on both sides of the bottom of the TBM. When carrying out the widening operation, a circle is drawn with the excavation axis of the tunnel design as the center and the excavation radius of the TBM cutterhead as the radius to obtain a circular widening section. The two areas on both sides of the bottom of the original arch-shaped tunnel section that do not coincide with the circular widening section are called area C. The two fan-shaped areas corresponding to area C on the circular widening section are called area A. The central angles of the two front shield plates (3) on the circular excavation section cover the central angles α of the two A regions on the circular excavation section; The central angles of the two shield plates (4) on the circular excavation section cover the central angles α of the two regions A on the circular excavation section.

2. The open-type TBM for tunnel widening according to claim 1, characterized in that: The gaps formed between the two front shield plates (3) and between the two middle shield plates (4) are drainage areas, and a pumping device is provided in the drainage areas.

3. The open-type TBM for tunnel widening according to claim 1 or 2, characterized in that: The rear support trolley (5) of the open TBM is provided with at least one pair of inclined wheels (6) and at least one pair of sliding shoes (7). Each pair of inclined wheels (6) is symmetrically arranged at the bottom of the rear support trolley (5), and the sliding shoes (7) are arranged on the inner side of the inclined wheels (6). Each pair of sliding shoes (7) is symmetrically arranged at the bottom of the rear support trolley (5).

4. The open-type TBM for tunnel widening according to claim 3, characterized in that: The inclined wheel (6) is inclined and has a protruding arc tread surface, which matches the circular excavation section.

5. The open-type TBM for tunnel widening according to claim 4, characterized in that: The slipper (7) is a boat-shaped structure that extends obliquely upward at both ends. The slipper (7) is inclined with the side closer to the center of the rear supporting trolley (5) being lower and the side closer to the edge of the rear supporting trolley (5) being higher. The bottom surface of the slipper (7) is an arc surface. The bottom surface of the slipper (7) matches the inner surface of the excavation trench formed by the cutterhead of the TBM at the bottom of the arch-shaped original tunnel.

6. The open-type TBM for tunnel widening according to claim 5, characterized in that: The bottom of the rear trolley (5) of the open TBM is provided with two pairs of inclined wheels (6) and two pairs of slippers (7).

7. The open-type TBM for tunnel widening according to claim 3, characterized in that: The middle part of the slipper (7) is fixedly connected to the bottom of the slipper bracket (73), the top of the slipper bracket (73) is rotatably engaged with the bottom of the connecting bracket (71) through the connecting pin (72), and the top of the connecting bracket (71) is fixedly connected to the bottom of the rear matching trolley (5).

8. A method for widening a tunnel, characterized in that, The tunnel widening method is based on the open-face TBM used for tunnel widening according to any one of claims 1-7, comprising: Based on the existing tunnel with an arch-shaped cross-section, the diameter of the open-face TBM used for widening is selected. An open-face TBM with a widening diameter larger than the width of the existing tunnel is selected, and the widening excavation face is determined so that the widening excavation face covers a part of the area below the ground of the existing tunnel. Based on the excavation face to be excavated, the selected open-face TBM is used to carry out the excavation operation.

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