Sawtooth-shaped steel lagging jack top-lifting structure of auxiliary tunnel of tunnel and construction method

Abstract

The invention discloses a sawtooth-shaped steel arch jacking structure of an auxiliary tunnel of a tunnel and a construction method. A rectangular reinforcing ring portal in a traditional jacking construction method is replaced with a sawtooth-shaped reinforcing ring portal, so that the excavation area is reduced, the usage amount of a steel arch and concrete in the jacking construction process is reduced, the construction quality is improved, and meanwhile disturbance to surrounding rock is reduced; before guniting, sandbags are stacked on the cross beams of the sawtooth-shaped reinforcing rings and fixed in place, the guniting amount is reduced, and it is avoided that the lagging jack is damaged due to the fact that sprayed concrete is broken and removed in the later period.

Description

Technical Field

[0001] The invention relates to the technical field of tunnel construction, and in particular to a tunnel auxiliary tunnel sawtooth steel arch frame cantilever structure and a construction method. Background Art

[0002] During the construction of the auxiliary tunnel to the main tunnel, a rectangular portal frame is usually used for the reinforcement ring at the intersection with the main tunnel. It has a poor connection with the reinforcing arch frame and cannot play a role in strengthening the structural strength. In addition, the excavation surface is large, which can easily cause the surrounding rock to become unstable. The subsequent primary support and secondary lining construction consumes a lot of concrete. The structural appearance of the triangular area within the portal frame is too rigid, the quality of the finished waterproofing construction is poor, and it is easy to cause loss of primary spraying materials.

[0003] Therefore, it is necessary to develop a tunnel auxiliary tunnel sawtooth steel arch frame cantilever structure and construction method to solve the above problems. Summary of the invention

[0004] The purpose of the present invention is to design a tunnel auxiliary tunnel sawtooth steel arch frame cantilever structure and construction method in order to solve the above problems.

[0005] The present invention achieves the above-mentioned purpose through the following technical solutions: The serrated steel arch frame cantilevered roof structure of the tunnel auxiliary tunnel is arranged at the intersection of the auxiliary tunnel and the main tunnel, the auxiliary tunnel includes a plurality of arch frames arranged along the length direction, the main tunnel includes a plurality of main tunnel initial support steel frames arranged along the length direction, and the steel arch frame cantilevered roof structure includes a serrated reinforcement ring; the serrated reinforcement ring includes a plurality of cross beams and a plurality of columns, the cross beams and the columns are alternately distributed and connected end to end, the cross beams and the columns form a serrated gate arch structure; the serrated reinforcement ring is installed on an arch frame close to the main tunnel, and the top of the serrated reinforcement ring is connected to one end of the plurality of main tunnel initial support steel frames.

[0006] Specifically, the middle part of a cross beam at the top, one end of the remaining cross beams, and one side of the bottom of the columns at both sides are fixedly connected to an arch frame close to the main hole.

[0007] Specifically, the gaps between the beams, columns and arch frames are filled with sandbags.

[0008] Specifically, one ends of a plurality of main tunnel initial support steel frames are respectively fixedly installed on a plurality of cross beams.

[0009] The construction method of the sawtooth steel arch cantilever structure of the tunnel auxiliary tunnel includes: Step a: When the auxiliary tunnel is close to the main tunnel, the slope is adjusted by using the shed tunnel according to the height difference between the auxiliary tunnel and the main tunnel vault. When constructing the shed tunnel, the slope is adjusted and gradually raised to the main tunnel vault; Step b: According to the oblique intersection angle between the auxiliary tunnel and the main tunnel, a sawtooth reinforcement ring is processed and manufactured at the intersection section in accordance with the design support parameter requirements of the auxiliary tunnel, so that the connection section between the auxiliary tunnel and the main tunnel can smoothly transition; Step c: First, complete the construction of the auxiliary tunnel arch near the main tunnel. After the arch support is completed, construct the zigzag reinforcement ring of the intersection section; Step d: Excavate the rectangular shed uphill to the center of the main tunnel according to the vertical direction of the main tunnel, and then excavate forward flatly to the arch foot of the upper guide pit outside the main tunnel, and follow up with temporary shed support in time; Step e: After the construction of the shed tunnel is completed, the initial support steel frame of the main tunnel is installed according to the designed support measures, and the initial support steel frame of the main tunnel is connected to the zigzag reinforcement ring.

[0010] Specifically, in step b, when the arch frame is installed at the oblique intersection of the auxiliary tunnel and the main tunnel, the arch frame is arranged in a manner that deviates from the normal line, and the long side of the auxiliary tunnel close to the main tunnel is set according to the normal arch frame pitch, and the short side pitch is smaller than the long side.

[0011] Specifically, in step c, a serrated reinforcement ring section is excavated by blasting, and the serrated reinforcement ring is installed on an arch frame close to the main tunnel. The top of the serrated reinforcement ring is connected to one end of multiple main tunnel initial support steel frames, and sandbags are filled in the gap between the serrated reinforcement ring and the arch frame.

[0012] Specifically, in step d, a rectangular scaffold and shed hole are constructed. The scaffold is made of I18 steel with a spacing of 100 cm, and 4 φ42 locking foot anchor pipes are set.

[0013] Specifically, in step e, a steel pad is set at one end of multiple main tunnel initial support steel frames at the intersection of the auxiliary tunnel and the main tunnel, and a connecting plate is correspondingly set on multiple crossbeams of the zigzag reinforcement ring, and the steel pad is connected to the connecting plate by bolts. The other end of the main tunnel initial support steel frame is supported by a concrete pad, and two φ42 locking foot anchor pipes with a length of 4m are respectively applied at the sections and arch feet of the main tunnel initial support steel frame; φ6 steel mesh is set between adjacent main tunnel initial support steel frames, with a grid spacing of 25x25cm, and then mortar anchor rods with a length of 2.5m and a diameter of 22mm are arranged in a 1.0x1.0m plum blossom shape, and the sprayed concrete strength is C25 and the thickness is 25cm; after the initial support construction of the main tunnel in the shed tunnel is completed, the upper step of the main tunnel is excavated and supported, and the heading face is closed after the excavation and support of the upper step of the main tunnel is completed for about 10m, and then the temporary support on the other side of the shed tunnel is removed, and the upper step of the main tunnel on the other side is excavated and supported.

[0014] The beneficial effects of the present invention are: The present application reduces the excavation area and the amount of steel arch frames and concrete used in the cantilever construction process by replacing the rectangular reinforcement ring gantry in the traditional cantilever construction method with a sawtooth reinforcement ring gantry, thereby improving the construction quality and reducing the disturbance to the surrounding rock. Before spraying, sandbags are stacked on the crossbeams of the sawtooth reinforcement ring and fixed in place to reduce the amount of spraying and avoid damage to the arch frame caused by the later removal of the sprayed concrete. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is a schematic diagram of the auxiliary tunnel being jacked into the main tunnel; Figure 2 This is a top view of the auxiliary tunnel being pushed into the main tunnel; the oblique angle between the auxiliary tunnel and the main tunnel is 90°; Figure 3 This is a top view of the auxiliary tunnel being pushed into the main tunnel; the oblique angle between the auxiliary tunnel and the main tunnel is 45°; Figure 4 This is the front view of the sawtooth reinforced ring support for the auxiliary tunnel top; Figure 5 This is a schematic diagram of the auxiliary tunnel top main tunnel and the auxiliary tunnel initial support layout; Figure 6 Schematic diagram of the steel frame setting for the auxiliary tunnel cantilevered ceiling hole.

[0016] In the figure: 1. Auxiliary tunnel; 2. Main tunnel; 3. Arch frame; 4. Sawtooth reinforcement ring; 5. Scaffolding; 8. Crossbeam; 9. Column; 10. Locking foot anchor pipe; 11. Steel mesh; 12. Mortar anchor rod; 13. Main tunnel initial support steel frame; 14. Steel pad; 15. Connecting plate. DETAILED DESCRIPTION

[0017] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings here can be arranged and designed in various different configurations.

[0018] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the invention claimed for protection, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0019] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, further definition and explanation thereof is not required in subsequent drawings.

[0020] In the description of the present invention, it should be understood that the terms "upper", "lower", "inside", "outside", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships shown in the accompanying drawings, or are directions or positional relationships in which the product of the invention is usually placed when in use, or are directions or positional relationships commonly understood by those skilled in the art. These directions or positional relationships are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore should not be understood as a limitation on the present invention.

[0021] Furthermore, the terms “first”, “second”, etc. are merely used for distinguishing descriptions and should not be understood as indicating or implying relative importance.

[0022] In the description of the present invention, it is also necessary to explain that, unless otherwise clearly specified and limited, the terms such as "setting" and "connection" should be understood in a broad sense. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0023] The specific implementation modes of the present invention are described in detail below in conjunction with the accompanying drawings.

[0024] like Figure 1-5 As shown, the zigzag steel arch frame cantilever structure of the auxiliary tunnel of the tunnel is arranged at the intersection of the auxiliary tunnel 1 and the main tunnel 2. The auxiliary tunnel 1 includes multiple arched arch frames 3 arranged along the length direction, and the main tunnel 2 includes multiple main tunnel initial support steel frames 13 arranged along the length direction. The steel arch frame 3 cantilever structure includes a zigzag reinforcement ring 4; the zigzag reinforcement ring 4 includes seven crossbeams 8 and eight columns 9, and the crossbeams 8 and the columns 9 are alternately distributed and connected end to end, and the crossbeams 8 and the columns 9 form a zigzag gate arch structure; the zigzag reinforcement ring 4 is installed on an arch frame 3 close to the main tunnel 2, and the top of the zigzag reinforcement ring 4 is connected to one end of the multiple main tunnel initial support steel frames 13. The middle part of a crossbeam 8 at the top, one end of the remaining crossbeams 8, and one side of the bottom of the columns 9 on both sides are fixedly connected to an arch frame 3 close to the main tunnel 2. The gaps between the crossbeams 8, the columns 9 and the arch frame 3 are filled with sandbags. One ends of the plurality of main tunnel initial support steel frames 13 are fixedly mounted on the plurality of cross beams 8 respectively.

[0025] The construction method of the sawtooth steel arch cantilever structure of the tunnel auxiliary tunnel includes: Step a: When the distance between the excavation working face of the auxiliary tunnel 1 and the main tunnel 2 is less than 10m, adjust the blasting parameters, reduce the cycle footage, and reduce the disturbance of blasting to the surrounding rock of the main tunnel 2. When the auxiliary tunnel 1 is close to the main tunnel 2, according to the height difference between the arch of the auxiliary tunnel 1 and the main tunnel 2, the slope is adjusted by using the shed tunnel. When constructing the shed tunnel, the slope is adjusted and gradually raised to the arch of the main tunnel 2; Step b: According to the oblique intersection angle between the auxiliary tunnel 1 and the main tunnel 2, the sawtooth reinforcement ring 4 of the intersection section is processed and manufactured according to the design support parameter requirements of the auxiliary tunnel 1; when the arch frame 3 is installed at the oblique intersection of the auxiliary tunnel 1 and the main tunnel 2, the arch frame 3 is arranged in a manner deviating from the normal line, and the long side of the auxiliary tunnel 1 close to the main tunnel 2 is set according to the normal arch frame 3 step, and the short side step is smaller than the long side, so that the connection section between the auxiliary tunnel 1 and the main tunnel 2 has a smooth transition, so as to ensure that when the shed tunnel is constructed, the excavation face of the shed tunnel is orthogonal to the line direction of the main tunnel 2; Figure 2 As shown, the oblique angle between the auxiliary tunnel 1 and the main tunnel 2 is 90°; Figure 3 As shown, the oblique angle between the auxiliary tunnel 1 and the main tunnel 2 is 45°; Step c: First, complete the construction of the arch frame 3 of the auxiliary tunnel 1 near the main tunnel 2. After the support of the arch frame 3 is completed, construct the zigzag reinforcement ring 4 of the intersection section; use blasting to excavate the section of the zigzag reinforcement ring 4, weld the zigzag reinforcement ring 4 on an arch frame 3 near the main tunnel 2, and connect the top of the zigzag reinforcement ring 4 to one end of multiple main tunnel initial support steel frames 13, fill the gap between the zigzag reinforcement ring 4 and the arch frame 3 with sandbags to reduce the amount of spraying and avoid damage to the arch frame 3 caused by the later removal of the sprayed concrete. Adjacent arch frames 3 are connected by longitudinal steel bars with a diameter of 22mm, with a spacing of 1m.

[0026] Step d: A rectangular shed tunnel is excavated uphill in a vertical direction to the center of the main tunnel 2, and then excavated forward flatly to the arch foot of the upper guide pit on the outer side of the main tunnel 2. The temporary support of the shed 5 is followed up in time. The excavation advance of each cycle of the shed tunnel excavation is not more than 4 frames. The next cycle of excavation can only be carried out after the initial support is completed; the rectangular shed 5 and the shed tunnel are constructed. The shed 5 is made of I18 steel with a spacing of 100cm, and 4 φ42 locking foot anchor pipes 10 are set.

[0027] Step e: After the construction of the shed tunnel is completed, the initial support steel frame 13 of the main tunnel is installed according to the designed support measures, and the initial support steel frame 13 of the main tunnel is connected to the zigzag reinforcement ring 4. A steel pad 14 is set at one end of the multiple initial support steel frames 13 of the main tunnel at the intersection of the auxiliary tunnel 1 and the main tunnel 2, and a connecting plate 15 is welded on the multiple crossbeams 8 of the zigzag reinforcement ring 4 accordingly. The steel pad 14 and the connecting plate 15 are fixed with high-strength bolts one positive and one negative, so as to improve the installation efficiency of the steel frame (13); the other end of the initial support steel frame 13 of the main tunnel is supported by a concrete pad, and 4m long φ42 locking foot anchor pipes 102 are installed at the sections and arch feet of the initial support steel frame 13 of the main tunnel; the adjacent initial support steel frames of the main tunnel are fixed with a steel pad 14 and a connecting plate 15. φ6 steel mesh 11 is set between the supporting steel frames 13, with a grid spacing of 25x25cm, and then mortar anchor rods 12 with a length of 2.5m and a diameter of 22mm are arranged in a plum blossom shape of 1.0x1.0m. The sprayed concrete strength is C25 and the thickness is 25cm. After the initial support construction of the main tunnel 2 in the shed tunnel is completed, the upper step of the main tunnel 2 is excavated and supported. After about 10m of the excavation and support of the upper step of the main tunnel 2 is completed, the heading face is closed, and then the temporary support on the other side of the shed tunnel is removed, and the upper step of the main tunnel 2 on the other side is excavated and supported.

[0028] The present application reduces the excavation area and the usage of the steel arch frame 3 and concrete during the cantilever construction process by replacing the traditional rectangular portal frame with a sawtooth portal frame in the cantilever construction method, thereby improving the construction quality and reducing the disturbance to the surrounding rock.

[0029] The present application adds a steel frame connecting plate 15 at the corner of the sawtooth portal frame, and uses high-strength bolts to fix the reinforced ring arch frame 3 in a positive and negative manner, so that the arch frame 3 and the sawtooth portal frame can be connected accurately and quickly.

[0030] The present application utilizes sandbags to be stacked on the sawtooth steel frame cross beam 8 before spraying and fixed in place, so as to reduce the amount of spraying and avoid damage to the arch frame 3 caused by the later removal of the sprayed concrete.

[0031] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. The zigzag steel arch frame cantilever structure of the tunnel auxiliary tunnel is arranged at the intersection of the auxiliary tunnel and the main tunnel. The auxiliary tunnel includes a plurality of arch frames arranged along the length direction, and the main tunnel includes a plurality of main tunnel initial support steel frames arranged along the length direction, characterized in that: The steel arch cantilever structure includes a serrated reinforcement ring; the serrated reinforcement ring includes multiple beams and multiple columns, the beams and columns are alternately distributed and connected end to end, and the beams and columns form a serrated arch structure; the serrated reinforcement ring is installed on an arch frame close to the main tunnel, and the top of the serrated reinforcement ring is connected to one end of multiple main tunnel initial support steel frames.

2. The tunnel auxiliary tunnel sawtooth steel arch frame cantilever structure and construction method according to claim 1 is characterized in that: The middle part of a cross beam at the top, one end of the remaining cross beams, and one side of the bottom of the columns at both sides are fixedly connected to an arch frame close to the main hole.

3. The tunnel auxiliary tunnel sawtooth steel arch frame cantilever structure and construction method according to claim 2 is characterized in that: The gaps between beams, columns and arches are filled with sandbags.

4. The tunnel auxiliary tunnel sawtooth steel arch frame cantilever structure and construction method according to claim 1 is characterized in that: One ends of multiple main tunnel initial support steel frames are respectively fixedly installed on multiple cross beams.

5. The construction method of the sawtooth steel arch cantilever structure of the tunnel auxiliary tunnel according to any one of claims 1 to 4, characterized in that: include: Step a: When the auxiliary tunnel is close to the main tunnel, the slope is adjusted by using the shed tunnel according to the height difference between the auxiliary tunnel and the main tunnel vault. When constructing the shed tunnel, the slope is adjusted and gradually raised to the main tunnel vault; Step b: According to the oblique intersection angle between the auxiliary tunnel and the main tunnel, a sawtooth reinforcement ring is processed and manufactured at the intersection section in accordance with the design support parameter requirements of the auxiliary tunnel, so that the connection section between the auxiliary tunnel and the main tunnel can smoothly transition; Step c: First, complete the construction of the auxiliary tunnel arch near the main tunnel. After the arch support is completed, construct the zigzag reinforcement ring of the intersection section; Step d: Excavate the rectangular shed uphill to the center of the main tunnel according to the vertical direction of the main tunnel, and then excavate forward flatly to the arch foot of the upper guide pit outside the main tunnel, and follow up with temporary shed support in time; Step e: After the construction of the shed tunnel is completed, the initial support steel frame of the main tunnel is installed according to the designed support measures, and the initial support steel frame of the main tunnel is connected to the zigzag reinforcement ring.

6. The construction method according to claim 5, characterized in that: In step b, when installing the arch frame at the oblique intersection of the auxiliary tunnel and the main tunnel, the arch frame is arranged in a manner that deviates from the normal line, and the long side of the auxiliary tunnel close to the main tunnel is set according to the normal arch frame pitch, and the short side pitch is smaller than the long side.

7. The construction method according to claim 5, characterized in that: In step c, blasting is used to excavate the section of the serrated reinforcement ring, and the serrated reinforcement ring is installed on an arch frame close to the main tunnel. The top of the serrated reinforcement ring is connected to one end of multiple main tunnel initial support steel frames, and sandbags are filled in the gap between the serrated reinforcement ring and the arch frame.

8. The construction method according to claim 5, characterized in that: In step d, the rectangular scaffolding and shed hole are constructed. The scaffolding is made of I18 steel with a spacing of 100 cm, and 4 φ42 locking foot anchor pipes are set.

9. The construction method according to claim 5, characterized in that: In step e, a steel pad is provided at one end of multiple primary support steel frames of the main tunnel at the intersection of the auxiliary tunnel and the main tunnel, and a connecting plate is correspondingly provided on multiple cross beams of the zigzag reinforcement ring, and the steel pad and the connecting plate are connected by bolts. The other end of the primary support steel frame of the main tunnel is supported by a concrete pad, and two φ42 locking foot anchor pipes with a length of 4m are respectively installed at the sections and arch feet of the primary support steel frame of the main tunnel; φ6 steel mesh is set between the adjacent main tunnel initial support steel frames with a grid spacing of 25x25cm, and then 2.5m long and 22mm diameter mortar anchor rods are arranged in a 1.0x1.0m plum blossom shape. The sprayed concrete strength is C25 and the thickness is 25cm. After the initial support construction of the main tunnel in the shed tunnel is completed, the upper steps of the main tunnel are excavated and supported. After about 10m of the excavation and support of the upper steps of the main tunnel are completed, the heading face is closed, and then the temporary support on the other side of the shed tunnel is removed, and the upper steps of the main tunnel on the other side are excavated and supported.

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