Underground excavation tunnel-entering advance pipe shed support and construction method

Abstract

The invention provides an underground excavation tunnel-entering advance pipe shed support which comprises a base, the bottom of the base forms a plane, and two sets of fan-shaped grooves are symmetrically formed in the peripheral side of the base; the supporting unit comprises a fixed supporting piece with one end fixedly arranged on the top of the base and two sets of movable supporting pieces with one ends hinged into the corresponding fan-shaped grooves, the fixed supporting piece and the two movable supporting pieces are adjustable in length, and a fixed supporting arm is hinged to the end, away from the base, of the fixed supporting piece. Movable supporting arms are hinged to the ends, hinged to the base, of the two movable supporting pieces, and a plurality of sets of arc grooves are formed in the fixed supporting arm and the two movable supporting arms in an array mode; and the arc-shaped supporting rods are clamped in the corresponding arc grooves to form an arch body and are used for supporting the steel mold. The arc-shaped supporting rods can be tightly clamped through the multiple sets of arc grooves in the fixed supporting arm and the movable supporting arm, and a complete arch body supporting steel mold is formed. By means of the tightly-attached supporting mode, the shape of the inner formwork can be kept stable when the inner formwork is stressed, formwork splicing gap changes caused by unstable supporting are reduced, and the grout leakage risk can be greatly reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel and underground engineering construction, and in particular to a dark excavation tunneling advance pipe shed support and construction method. Background Art

[0002] In the process of dark excavation for underground projects such as tunnels and underground passages, advanced pipe-roof support is a commonly used advanced pre-support technology.

[0003] During the construction process, setting up the formwork is a crucial step in pipe-roof construction. Currently, extended steel pipes are often used to support the bottom of the inner formwork. However, this support method has numerous drawbacks: First, in complex underground construction environments, the connections of extended steel pipes are prone to loosening due to factors such as vibration and load changes, resulting in insufficient overall support stability and difficulty withstanding the high pressure generated during the subsequent grouting process, causing the inner formwork to shift and deform. Second, deformation of the inner formwork increases the gaps at the formwork joints, making it very easy for slurry to leak through the gaps during grouting. Leakage not only wastes a large amount of grouting material and increases construction costs, but also weakens the reinforcement effect of pipe-roof grouting on the surrounding rock, reducing the quality of the advanced pipe-roof support. Summary of the Invention

[0004] In response to the deficiencies in the prior art, the present invention provides a method for supporting and constructing a pipe-roofed structure for tunneling, which solves the problem in the prior art that the traditional support for the bottom of the inner formwork is unstable and easily leads to leakage.

[0005] According to an embodiment of the present invention, a pipe-roof support for advanced tunneling includes a base, a bottom forming a plane, and two groups of fan-shaped grooves symmetrically provided on the circumference; a support unit including a fixed support member fixedly provided at one end on the top of the base and two groups of movable support members hinged at one end in the corresponding fan-shaped grooves, the fixed support member and the two movable support members can both be adjusted in length, the end of the fixed support member away from the base is hinged with a fixed support arm, the ends of the two movable support members are hinged with movable support arms hinged at the ends away from the base, and a plurality of groups of arc grooves are arranged in an array on the fixed support arm and the two movable support arms; a plurality of groups of arc-shaped struts are clamped in the corresponding arc grooves to form an arch body for supporting the steel formwork.

[0006] Compared with the existing technology, the present invention has the following beneficial effects: a stable foundation is provided by the bottom plane design of the base, and the symmetrical fan-shaped grooves on the circumferential side provide flexible hinge points for the movable support parts. In combination with the fixed support parts and movable support parts with adjustable lengths, the support angle and height can be accurately adjusted according to the actual shape, size and load conditions of the inner template to form a stable triangular support structure; the multiple sets of arc grooves on the fixed support arms and the movable support arms can tightly clamp the arc-shaped struts to form a complete arch supporting steel template. This tightly fitting support method can keep the steel template (inner template) stable in shape when under stress, and reduce the change in the template splicing gap caused by unstable support. At the same time, the stable support effectively prevents the template from deforming and shifting under the grouting pressure, and the sealing measures at the template joints can greatly reduce the risk of slurry leakage.

[0007] Preferably, the fixed support member and the two movable support members both include an outer arm and a screw, a receiving hole is provided at one end of the outer arm, and one end of the screw is slidably arranged in the receiving hole, wherein a nut is threadedly connected to the screw, the nut is located outside the receiving hole, and abuts against the end of the outer arm.

[0008] Preferably, a connecting seat is fixedly provided at one end of each screw away from the outer arm, and the fixed support arm and the two movable support arms are hinged to the corresponding connecting seats.

[0009] Preferably, each outer arm is provided with a travel slot passing through the corresponding receiving hole, and a limit block is fixedly provided at one end of each screw away from the connecting seat, and the limit block is located in the corresponding travel slot.

[0010] Preferably, a plurality of groups of adjustment holes are mirrored on the base, and each adjustment hole passes through a corresponding fan-shaped slot. A through slot is provided at one end of each outer arm near the hinge point, and the through slot overlaps with the corresponding adjustment hole and is penetrated by a pin.

[0011] Preferably, each arc-shaped strut includes an A strut and a B strut, wherein a connecting shaft is provided at one end of the A strut, and a connecting hole is provided at one end of the B strut, and the connecting shaft is inserted into the corresponding connecting hole.

[0012] Preferably, a clamping plate is provided at the connection point between the A support rod and the connecting shaft and at one end of the B support rod where the connecting hole is opened. The two clamping plates abut against each other, and multiple groups of recessed grooves are distributed on the fixed support arm. Each arc groove passes through the corresponding recessed groove, wherein each mutually abutting clamping plate is clamped in the corresponding recessed groove.

[0013] Preferably, both the A struts and the B struts are provided with cut surfaces.

[0014] Preferably, a locking groove is provided on the wall of each adjustment hole along the axial direction, and locking blocks are provided at both ends of each latch.

[0015] On the other hand, according to an embodiment of the present invention, the present invention also provides a construction method for advance pipe-roof support for concealed excavation, comprising the following steps: S1, advance pipe-roof arch: staking out the arch reinforcement position at the designated position, and tying the arch main reinforcement, stirrups and connecting reinforcement; S2, template arch installation: installing the inner and outer templates of the arch, the templates should be firm and tightly spliced ​​to prevent leakage; S3, supporting the template: placing the required arc-shaped struts at the bottom of the inner template, and then adjusting the fixed support and the two movable support members to the length so that each arc groove is clamped in the corresponding arc-shaped strut to form an arch body to support the template; S4, pouring concrete: pouring concrete in layers from the base of the arch upwards. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the three-dimensional structure of an embodiment of the present invention.

[0017] Figure 2 Schematic diagram of the explosion structure of an embodiment of the present invention.

[0018] Figure 3 Schematic diagram of the exploded structure of the support unit in an embodiment of the present invention.

[0019] Figure 4 Schematic diagram of the three-dimensional structure of the arc-shaped support rod in an embodiment of the present invention.

[0020] Figure 5 for Figure 4 Magnified view of area A in center.

[0021] Figure 6 2 is a cross-sectional view of the base in an embodiment of the present invention.

[0022] Figure 7 for Figure 6 Magnified view of area B.

[0023] In the above drawings: 10, base; 11, fan-shaped groove; 112, adjustment hole; 113, lock groove; 20, latch; 201, lock block; 30, outer arm; 301, through groove; 302, travel groove; 303, storage hole; 31, movable support arm; 311, arc groove; 32, fixed support arm; 321, sinking groove; 33, screw; 331, limit block; 332, connecting seat; 34, nut; 40, arc support rod; 41, support rod A; 411, connecting shaft; 42, support rod B; 422, connecting hole; 44, clamping plate; 45, cross section. DETAILED DESCRIPTION

[0024] The technical solution of the present invention is further described below with reference to the accompanying drawings and embodiments.

[0025] like Figures 1 to 7As shown, an embodiment of the present invention proposes an advance pipe-roof support for dark excavation, comprising a base 10, a bottom forming a plane, and two groups of fan-shaped grooves 11 symmetrically provided on the circumferential side; a support unit, comprising a fixed support member fixedly provided at one end on the top of the base 10 and two groups of movable support members hinged at one end in the corresponding fan-shaped grooves 11, the fixed support member and the two movable support members both being adjustable in length, the end of the fixed support member away from the base 10 being hinged with a fixed support arm 32, the ends of the two movable support members being hinged with ends away from the base 10 being hinged with movable support arms 31, a plurality of groups of arc grooves 311 are arranged in an array on the fixed support arm 32 and the two movable support arms 31; a plurality of groups of arc-shaped struts 40 are clamped in the corresponding arc grooves 311 to form an arch body for supporting the steel formwork.

[0026] The detailed working process of this embodiment is as follows: a stable foundation is provided by the bottom plane design of the base 10, and the symmetrical fan-shaped grooves 11 on the circumferential side provide flexible hinge points for the movable support parts. In combination with the fixed support parts and movable support parts with adjustable lengths, the support angle and height can be accurately adjusted according to the actual shape, size and load conditions of the inner template to form a stable triangular support structure; the multiple groups of arc grooves 311 on the fixed support arm 32 and the movable support arm 31 can tightly clamp the arc-shaped support rods 40 to form a complete arch supporting steel mold. This tightly fitting support method can keep the steel mold (inner template) stable in shape when under stress, and reduce the change in the template splicing gap caused by unstable support. At the same time, the stable support effectively prevents the template from deforming and shifting under the grouting pressure, and the sealing measures at the template joints can greatly reduce the risk of slurry leakage.

[0027] The adjustable lengths of each support unit component make the support structure adaptable to internal formwork of varying sizes and shapes, as well as diverse construction scenarios. Whether it's tunnel sections of varying sizes or construction under complex geological conditions, the support structure parameters can be adjusted to quickly adapt to construction needs. Furthermore, the support structure can be reused to maximize utilization.

[0028] like Figure 3 As shown, the fixed support member and the two movable support members include an outer arm 30 and a screw 33. A receiving hole 303 is provided at one end of the outer arm 30, and one end of the screw 33 is slidably set in the receiving hole 303, wherein a nut 34 is threadedly connected to the screw 33, and the nut 34 is located outside the receiving hole 303 and abuts against the end of the outer arm 30.

[0029] The detailed operating process of this embodiment is as follows: With the nut 34 in place, the screw 33 slides within the receiving hole 303 of the outer arm 30. By rotating the nut 34, which is threadedly connected to the screw 33, the overall extension length of the screw 33 can be changed. When the nut 34 abuts the end of the outer arm 30, friction is generated to lock the position, achieving adjustment of the support height. The threaded drive allows for continuous adjustment of any support length to accommodate varying height requirements.

[0030] The load is transferred to the nut 34 through the screw 33, and then borne by the contact surface between the nut 34 and the end of the outer arm 30, and finally transferred to the base.

[0031] like Figure 3 As shown, a connecting seat 332 is fixedly provided at one end of each screw rod 33 away from the outer arm 30 , and the fixed support arm 32 and the two movable support arms 31 are hinged to the corresponding connecting seat 332 .

[0032] The detailed working process of this embodiment is as follows: the fixed arm 32 and the two movable arms 31 are hinged to the corresponding connecting seat 332 so that the fixed arm 32 and the two movable arms 31 can be hinged along the hinge point. The hinge structure can enable the arm to automatically adjust the angle so that it fits perfectly with the arc-shaped support rod 40, thereby improving the supporting strength of the arc-shaped support rod 40.

[0033] like Figure 3 As shown, each outer arm 30 is provided with a travel slot 302 passing through the corresponding receiving hole 303 , and each screw rod 33 is fixedly provided with a limit block 331 at one end away from the connecting seat 332 , and the limit block 331 is located in the corresponding travel slot 302 .

[0034] The detailed working process of this embodiment is: through the cooperation between the limit block 331 and the travel groove 302, the maximum extension and contraction distance of the screw 33 is limited. The limit block 331 slides in the travel groove 302 to prevent it from escaping from the storage hole 303 or excessively retracting, and at the same time prevents the screw 33 from rotating, ensuring that when the nut 34 rotates, only the screw 33 is driven to move in a straight line, thereby improving the adjustment efficiency.

[0035] like Figure 6 and Figure 7 As shown, multiple groups of adjustment holes 112 are mirrored on the base 10, and each adjustment hole 112 passes through the corresponding fan-shaped slot 11. A through slot 301 is formed at one end of each outer arm 30 near the hinge point, and the through slot 301 overlaps with the corresponding adjustment hole 112 and is penetrated by a pin 20.

[0036] The detailed operating process of this embodiment is as follows: Multiple groups of adjustment holes 112 on the base 10 are distributed annularly along the fan-shaped slot 11, forming discrete angle adjustment points. After the through slot 301 of the outer arm 30 is aligned with the adjustment holes 112, the latch 20 passes through them to secure them. By selecting different adjustment holes 112 to insert the latch 20, the movable support member can achieve multiple angle adjustments within the fan-shaped slot 11.

[0037] The adjustment angle is related to the distribution of the adjustment holes 112 .

[0038] like Figure 4 and Figure 5As shown, each arc-shaped support rod 40 includes an A support rod 41 and a B support rod 42 . A connecting shaft 411 is provided at one end of the A support rod 41 , and a connecting hole 422 is opened at one end of the B support rod 42 . The connecting shaft 411 is inserted into the corresponding connecting hole 422 .

[0039] The detailed working process of this embodiment is as follows: the connection shaft 411 and the connection hole 422 cooperate to realize the rapid assembly and disassembly of the A support rod and the B support rod. The segmented design shortens the length of a single component by more than 50%, reduces the transportation space by 60%, and can be stacked for storage, significantly reducing transportation and warehousing costs.

[0040] like Figure 4 and Figure 5 As shown, a clamping plate 44 is provided at the connection between the A support rod 41 and the connecting shaft 411 and at one end of the B support rod 42 where the connecting hole 422 is opened. The two clamping plates 44 abut against each other, and multiple groups of recessed grooves 321 are evenly distributed on the fixed support arm 32. Each arc groove 311 passes through the corresponding recessed groove 321, wherein each mutually abutting clamping plate 44 is clamped in the corresponding recessed groove 321.

[0041] The detailed working process of this embodiment is as follows: the clamping plate 44 and the recessed groove 321 form a plane limit to prevent the arc-shaped support rod 40 from sliding in the horizontal direction; the arc groove 311 cooperates with the arc-shaped support rod 40 to achieve curved surface fitting and limit vertical displacement; the preset position and shape of the recessed groove 321 and the arc groove 311 provide a clear installation reference for the arc-shaped support rod 40.

[0042] During construction, workers simply align the clamping plates 44 with the grooves 321 and insert the arc-shaped struts 40 into the grooves 311 to complete positioning, significantly reducing measurement and adjustment time. Once the clamping plates 44 abut against each other and are locked in the grooves 321, the displacement of the A and B struts 41 and 42 is restricted, improving the support stability of the arc-shaped struts 40.

[0043] like Figure 4 and Figure 5 As shown, both the A support rod 41 and the B support rod 42 are provided with a cut surface 45 .

[0044] The detailed working process of this embodiment is as follows: by processing cross-sections of specific angles on the A support rod 41 and the B support rod 42, the support rods and the template form surface contact support, disperse stress, avoid point contact or line contact mode, and thus improve support efficiency and stability.

[0045] The surface contact between the section 45 and the formwork can convert the concentrated force (such as grouting pressure and concrete side pressure) borne by the strut into a uniformly distributed load. By increasing the contact area (assuming that the cross-sectional area of ​​a single strut is S and the traditional point contact area is S0, then S>>S0), the contact stress is significantly reduced (σ=F / S, σ represents the contact stress in Pascal (Pa); F is the load acting on the strut in Newton (N); S is the contact area in square meters (m2)). 2 )) to avoid deformation or damage of the template due to excessive local stress.

[0046] like Figure 7 As shown, a locking groove 113 is formed on the wall of each adjustment hole 112 along the axial direction, and a locking block 201 is provided at both ends of each latch 20 .

[0047] The detailed working process of this embodiment is as follows: With the cooperation of locking slot 113 and locking block 201, latch 20 is restrained in position. Latch 20 passes through through slot 301 and adjustment hole 112, and before insertion, locking block 201 is aligned with locking slot 113. Once latch 20 is in position, it is rotated to offset it from locking slot 11. Mechanical restraint prevents axial movement or disengagement of latch 200, ensuring the stability of the connection between outer arm 30 and base 10.

[0048] like Figures 1 to 7 As shown, a construction method for advance pipe-roof support in a concealed tunnel is also provided, comprising the following steps: S1, advance pipe-roof arch: staking out the position of the arch reinforcement at a designated position, and tying the arch main reinforcement, stirrups and connecting reinforcement; S2, template arch installation: installing the inner and outer templates of the arch, the templates should be firm and tightly spliced ​​to prevent leakage; S3, supporting the template: placing the required arc-shaped support rod 40 at the bottom of the inner template, and then adjusting the fixed support member and the two movable support members to the length so that each arc groove 311 is clamped on the corresponding arc-shaped support rod 40 to form an arch body to support the template; S4, pouring concrete: pouring concrete in layers from the base of the arch upwards.

[0049] The detailed working process of this embodiment is as follows: In step S1, advanced pipe-roof arching, connecting steel bars are installed according to design requirements. The connecting steel bars should be firmly connected to the main bars and stirrups to form a stable steel skeleton structure. The diameter, length, and spacing of the connecting steel bars should meet the design requirements. The connection method to the main bars can be welding or tying. The weld length and quality should meet the requirements of the specifications.

[0050] During S2, the formwork arch installation step: Steel or wooden formwork is typically used for the inner and outer formwork of the arch. Steel formwork offers high strength, high turnover, and resistance to deformation, making it suitable for large-scale construction. Wooden formwork offers flexibility and ease of cutting, making it suitable for complex arch shapes. During installation, the inner formwork should be installed first, followed by the outer formwork. The inner formwork must be precisely adjusted to the dimensions of the rebar skeleton to ensure that the protective layer thickness between the formwork and the rebar meets the design requirements (generally 3-5 cm). The outer formwork should be aligned with the inner formwork and secured using tension bolts, a support system, and other methods. The diameter and spacing of the tension bolts are determined based on formwork stress calculations. Generally, the diameter should be no less than 12 mm and the spacing should be no more than 60 cm to prevent deformation and displacement during concrete pouring. Tight formwork joints are key to preventing grout leakage. Tongue-and-groove joints, staggered joints, and other methods can be used to secure the joints. Sealing strips or sponge strips should be applied to the joints. If rubber sealing strips are used, they should be at least 2 cm wide and 5 mm thick to ensure a tight fit.

[0051] In S3, the step of supporting the formwork: a mechanical structure similar to a "three-hinge arch" is formed by combining the arc-shaped support rod 40 with the fixed support member and the movable support member. The length of the movable support member is changed by rotating the screw rod 33, so that the arc groove 311 slides along the arc-shaped support rod until the curvature of the formwork matches the design, thereby effectively supporting the formwork, improving the stability of the formwork, and avoiding construction problems such as leakage.

[0052] During S4, concrete pouring, lateral pressure is generated during concrete pouring. Layered pouring (each layer 30-50cm thick) reduces this total lateral pressure and releases it in multiple stages, preventing the formwork from deforming due to sudden high pressure. Based on the principles of fluid mechanics, layering reduces the maximum lateral pressure on the formwork. Controlling the pouring height of each layer reduces aggregate segregation during the concrete fall, ensuring concrete uniformity and improving structural strength.

[0053] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not limiting. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present invention may be modified or replaced by equivalents without departing from the purpose and scope of the technical solutions of the present invention, which should all be included in the scope of the claims of the present invention.

Claims

1. A kind of advanced pipe support for underground excavation, characterized by: include: The base (10) has a flat bottom and two sets of fan-shaped grooves (11) symmetrically formed on the circumference; The support unit comprises a fixed support member with one end fixedly arranged on the top of the base (10) and two groups of movable support members with one end hinged in the corresponding fan-shaped groove (11), the fixed support member and the two movable support members are both adjustable in length, the end of the fixed support member away from the base (10) is hinged to a fixed support arm (32), the ends of the two movable support members are hinged to the ends away from the base (10) and are hinged to movable support arms (31), and a plurality of groups of arc grooves (311) are arranged in an array on the fixed support arm (32) and the two movable support arms (31); A plurality of groups of arc-shaped support rods (40) are clamped in corresponding arc grooves (311) to form an arch body for supporting the steel mold.

2. The advanced pipe-roof support for underground excavation according to claim 1 is characterized by: The fixed support member and the two movable support members each include an outer arm (30) and a screw rod (33), one end of the outer arm (30) is provided with a receiving hole (303), one end of the screw rod (33) is slidably arranged in the receiving hole (303), wherein a nut (34) is threadedly connected to the screw rod (33), and the nut (34) is located outside the receiving hole (303) and abuts against the end of the outer arm (30).

3. The advanced pipe-roof support for underground excavation according to claim 2 is characterized by: A connecting seat (332) is fixedly provided at one end of each screw rod (33) away from the outer arm (30), and the fixed support arm (32) and the two movable support arms (31) are hinged to the corresponding connecting seat (332).

4. The advanced pipe-roof support for underground excavation according to claim 3 is characterized by: Each outer arm (30) is provided with a travel groove (302) passing through the corresponding receiving hole (303), and a limit block (331) is fixedly provided at one end of each screw rod (33) away from the connecting seat (332), and the limit block (331) is located in the corresponding travel groove (302).

5. The advanced pipe-roof support for underground excavation according to claim 4 is characterized in that: The base (10) is provided with a plurality of groups of adjustment holes (112) in a mirrored manner, and each of the adjustment holes (112) passes through the corresponding fan-shaped slot (11). A through slot (301) is provided at one end of each outer arm (30) near the hinge point, and the through slot (301) overlaps with the corresponding adjustment hole (112) and is provided with a latch (20).

6. The advanced pipe-roof support for underground excavation according to claim 1 is characterized by: Each of the arc-shaped support rods (40) includes an A support rod (41) and a B support rod (42). One end of the A support rod (41) is provided with a connecting shaft (411), and one end of the B support rod (42) is provided with a connecting hole (422). The connecting shaft (411) is inserted into the corresponding connecting hole (422).

7. The advanced pipe-roof support for underground excavation according to claim 6 is characterized by: A clamping plate (44) is provided at the connection point between the A support rod (41) and the connecting shaft (411) and at one end of the B support rod (42) where the connecting hole (422) is opened. The two clamping plates (44) abut against each other. A plurality of groups of sink grooves (321) are evenly distributed on the fixed support arm (32). Each arc groove (311) passes through the corresponding sink groove (321), wherein each mutually abutting clamping plate (44) is clamped in the corresponding sink groove (321).

8. The advanced pipe-roof support for underground excavation according to claim 6 is characterized by: The A support rod (41) and the B support rod (42) are both provided with a cut surface (45).

9. The advanced pipe-roof support for underground excavation according to claim 5 is characterized by: A locking groove (113) is provided on the wall of each adjusting hole (112) along the axial direction, and locking blocks (201) are provided at both ends of each latch (20).

10. The construction method for advanced pipe-roof support in a dark excavation tunnel according to any one of claims 1 to 9, characterized in that: The following steps are included: S1. Advance pipe-roof arch: Locate the arch reinforcement position at the designated location, and tie the arch main reinforcement, stirrups and connecting reinforcement; S2. Installation of formwork arch: Install the inner and outer formwork of the arch. The formwork should be firm and tightly spliced ​​to prevent slurry leakage; S3. Supporting the template: placing the required arc-shaped support rod (40) at the bottom of the inner template, and then adjusting the fixed support member and the two movable support members to the length so that each arc groove (311) is clamped on the corresponding arc-shaped support rod (40) to form an arch body to support the template; S4. Pouring concrete: Pour concrete in layers from the base of the arch upwards.

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