Adjustable initial support device for tunneling

Abstract

The utility model discloses a kind of tunnelling adjustable primary support device, it is related to tunnel construction field, including reinforcing mesh, several arc steel arch supports and adjustable fixing assembly for connecting arc steel arch support and reinforcing mesh, the arc steel arch support includes several steel arch supports that are connected head to tail and mutually spliced, the both ends of the steel arch support are provided with several groups of connecting lug plate, the lateral wall of the steel arch support is provided with several adjusting holes along its length direction, the length of the adjusting hole is greater than the grid aperture of reinforcing mesh, the adjustable fixing assembly includes locking washer, several locking pieces are arranged on the locking washer;The utility model is by being provided with the adjusting hole of length greater than the grid aperture of reinforcing mesh on steel arch support, cooperate locking screw that can slide along adjusting hole, can flexibly adjust fixed position according to reinforcing mesh laying demand, without secondary processing to steel arch support or reinforcing mesh, adapt to different tunnel section support demand.

Description

Technical Field

[0001] This utility model belongs to the field of tunnel construction, specifically an adjustable initial support device for mined tunnels. Background Technology

[0002] In the construction of mined tunnels, the initial support system is the core structure for ensuring tunnel excavation safety and controlling surrounding rock deformation. It typically consists of an arched steel arch support and a steel mesh. The arched steel arch support provides overall support, while the steel mesh distributes the load and prevents rock fragments from falling off. The two need to be tightly connected by fixing components to form a collaborative support system. In existing initial support systems, the connection between the arched steel arch support and the steel mesh often uses a fixed hole design. This means that the steel arch frame has pre-set fixed circular holes that match the mesh size of the steel mesh. The fixing components must be precisely aligned with the circular holes and the mesh openings to complete the connection.

[0003] In actual use, due to factors such as surrounding rock geological conditions and excavation accuracy during tunnel excavation, the actual tunnel cross-section shape often deviates from the design. It is difficult to completely fit the pre-set hole positions when laying the steel mesh. If the holes are forcibly aligned, it is easy to cause the steel mesh to be stretched and deformed or to have local wrinkles, affecting the flatness of the support and the uniformity of stress. The specifications of the steel mesh may vary between different tunnels or different sections of the same tunnel. When the mesh diameter of the steel mesh does not match the fixed circular holes of the steel arch, it is necessary to drill holes in the steel arch or cut and process the steel mesh. This not only increases the construction process and time cost, but may also damage the structural strength of the steel arch or reduce the effective stress area of ​​the steel mesh, leaving hidden dangers for support safety. Utility Model Content

[0004] The purpose of this invention is to provide an adjustable initial support device for mined tunnels, in order to solve the problems of fixed hole positions in existing initial support devices, which make it difficult to adapt to cross-sectional deviations and grid differences, resulting in low connection efficiency and potential safety hazards in support.

[0005] To achieve the above objectives, this utility model provides the following technical solution: an adjustable initial support device for mined tunnels, comprising a steel mesh, several arc-shaped steel arch supports, and an adjustable fixing component for connecting the arc-shaped steel arch supports and the steel mesh;

[0006] The arc-shaped steel arch support includes several steel arch frames that are connected end to end and spliced ​​together. Several sets of connecting ear plates are provided at both ends of the steel arch frame. Several adjustment holes are opened on the side wall of the steel arch frame along its length. The length of the adjustment holes is greater than the mesh diameter of the steel mesh.

[0007] The adjustable fixing component includes a locking washer, and the locking washer is provided with a plurality of locking elements, which are respectively disposed in corresponding adjustment holes for locking the reinforcing mesh.

[0008] Preferably, the outer sidewall of the steel arch frame is arc-shaped, and a plurality of anchoring holes are provided on the outer sidewall of the steel arch frame. The anchoring holes are used to connect with pre-embedded anchor rods. The length of the anchoring holes is greater than the length of the adjusting holes, and the locking element is located inside the anchoring holes.

[0009] Preferably, the locking component includes a locking screw that is slidably disposed in a corresponding adjustment hole, the end of the locking screw slidingly passing through the steel arch frame, the steel mesh, and the locking washer in sequence, and the end of the locking screw is threadedly connected to a locking nut.

[0010] Preferably, the locking washer has anti-slip teeth on the side facing the steel arch frame, and a spring washer is provided between the locking nut and the locking washer.

[0011] Preferably, the connecting ear plate is provided with a plurality of positioning holes along its length direction, and the steel arch frame is provided with a plurality of connecting holes that cooperate with the positioning holes. When adjacent steel arch frames are spliced, the corresponding positioning holes and connecting holes are aligned.

[0012] Preferably, a fastener is provided in the connecting hole, the fastener is located in the corresponding positioning hole, and is used to fix the adjacent steel arch frame. The fastener is a high-strength bolt.

[0013] Preferably, the edge of the steel mesh is provided with a reinforcing frame, which is welded and fixed to the mesh reinforcement of the steel mesh.

[0014] Preferably, a wear-resistant bushing is provided on the inner edge of the adjustment hole, and the wear-resistant bushing is embedded in the adjustment hole by interference fit.

[0015] Compared with the prior art, the present invention has the following beneficial effects:

[0016] 1. This utility model, by opening adjustment holes on the steel arch frame with a length greater than the mesh diameter of the reinforcing mesh, and cooperating with locking screws that can slide along the adjustment holes, can flexibly adjust the fixed position according to the requirements of the reinforcing mesh laying, without the need for secondary processing of the steel arch frame or the reinforcing mesh, adapting to the support requirements of different tunnel sections, and solving the problems of poor adaptability and inability to flexibly adjust the position of the reinforcing mesh in existing devices.

[0017] 2. This utility model features a double anti-loosening design, with anti-slip teeth on the locking washer and spring washers on the locking nut, preventing the steel mesh from loosening after fixing. The adjustment hole has a built-in wear-resistant bushing to reduce sliding wear of the locking screw, extend the service life of the device, and reduce later maintenance costs. It is especially suitable for the harsh construction environment of tunnels with moisture and dust. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this utility model. For those skilled in the art, other drawings can be obtained based on these drawings.

[0019] Figure 1 This is a first-view perspective three-dimensional structural diagram of an embodiment of the present utility model;

[0020] Figure 2 This is a second-view perspective three-dimensional structural diagram provided for an embodiment of the present utility model;

[0021] Figure 3 A three-dimensional structural diagram of the steel arch frame and its associated components provided for an embodiment of this utility model.

[0022] In the picture:

[0023] 1. Arched steel arch support; 101. Steel arch frame; 102. Connecting ear plate; 2. Adjustable fixing component; 201. Locking washer; 202. Locking screw; 203. Locking nut; 3. Reinforcing mesh; 4. Fastener; 5. Adjustment hole; 6. Anchoring hole; 7. Positioning hole. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of this utility model, the present utility model will be further described in detail below with reference to the accompanying drawings.

[0025] As attached Figure 1 To be continued Figure 3 As shown:

[0026] This utility model provides an adjustable initial support device for mined tunnels, including a steel mesh 3, several arc-shaped steel arch supports 1, and an adjustable fixing component 2 for connecting the arc-shaped steel arch supports 1 and the steel mesh 3. The arc-shaped steel arch supports 1 include several steel arch frames 101 connected end to end. Each end of the steel arch frame 101 is provided with several sets of connecting ear plates 102. The side wall of the steel arch frame 101 is provided with several adjustment holes 5 along its length. The length of the adjustment holes 5 is greater than the mesh diameter of the steel mesh 3. The adjustable fixing component 2 includes a locking shim 201. The locking shim 201 is provided with several locking elements. The locking elements are respectively set in the corresponding adjustment holes 5 for locking the steel mesh 3.

[0027] The steel arch frame 101 of the arc-shaped steel arch support 1 is made of H150×150×7×10Q355B steel (curvature radius 3-8m to adapt to tunnel cross section). The side wall has 25-50mm long strip adjustment holes 5 (spacing 300mm) along its length. The length of the adjustment hole 5 is greater than the 100mm×100mm-200mm×200mm mesh diameter of the steel mesh 3. Two sets of 100mm×80mm×10mmQ355B connecting ear plates 102 (symmetrically arranged) are welded to each end of the steel arch frame 101. The inner side is welded with 100mm×50mm×8mmQ355B reinforcing ribs (spacing 300mm, with Φ30mm weight reduction holes). The outer side is welded with Φ50mm×150mm×5mmQ355B anchoring holes 6 (spacing 500mm, axis perpendicular to the outer wall). The reinforcing mesh 3 is made of HRB400 threaded steel welded together (mesh size 100mm×100mm), with a Φ12mm HRB400 reinforced frame welded to the edge (welding length ≥100mm), and the overlap between adjacent reinforcing meshes 3 is ≥200mm. The locking washer 201 of the adjustable fixing component 2 is a 50mm×30mm×5mm Q235 steel plate (with anti-slip teeth 1mm high × 2mm distance on one side), and the locking part is a Φ14mm×100mm long 40Cr T-type locking screw 202 (head 25mm×25mm×8mm snap-fit ​​adjustment hole 5), and the end passes through the steel arch frame 101, the reinforcing mesh 3, and the locking washer 201 before connecting to an M1445# steel locking nut 203 (equipped with a 14mm spring washer); the adjustment hole 5 is embedded with a 2mm thick brass wear-resistant bushing (interference fit, polishing Ra≤0.8μm). Connecting ear plates 102 have Φ20mm positioning holes 7 (50mm spacing) and Φ18mm bolt holes. When splicing adjacent steel arch frames 101, positioning holes 7 are fitted with Φ19.8mm × 120mm long 40Cr positioning pins, and M16 × 808.8 grade high-strength bolts 4 (two symmetrically distributed per ear plate group) are used. Q355B expansion joints (inner sleeve Φ140mm × outer sleeve Φ150mm, overlapping 200mm, fixed with M12 × 30 bolts, adjustable ±100mm) are installed at both ends of the steel arch frame 101. 50mm × 50mm × 30mm C50 concrete isolation blocks (500mm spacing, ensuring a 30mm protective layer) are placed between the reinforcing mesh 3 and the steel arch frame 101.

[0028] During operation, workers first assemble the arc-shaped steel arch support 1: align the connecting ear plates 102 of adjacent steel arch frames 101, insert positioning pins for positioning, insert fasteners 4, and tighten nuts for fixation; according to the tunnel surrounding rock conditions, insert pre-embedded anchor rods (Φ22mm × length 2.5-3m) into anchoring holes 6 to fix the arc-shaped steel arch support 1. When laying the reinforcing mesh 3, insert the head of the locking screw 202 of the adjustable fixing component 2 into the adjustment hole 5, slide it along the adjustment hole 5 to the appropriate position, and pass the end of the screw through the steel arch frame 101, reinforcing mesh 3, and locking washer 201, then tighten the locking nut 203; anti-slip teeth and spring washers provide double anti-loosening, and wear-resistant bushings reduce screw sliding wear. Through the adjustment hole 5 and sliding locking component, the fixing position of the reinforcing mesh 3 can be flexibly adjusted without secondary processing, adapting to the support needs of different tunnel sections, improving construction efficiency and support stability.

[0029] As attached Figure 1 To be continued Figure 3 As shown: In one embodiment of this utility model, the outer sidewall of the steel arch frame 101 is arc-shaped, and a plurality of anchor holes 6 are provided on the outer sidewall of the steel arch frame 101. The anchor holes 6 are used to connect with the pre-embedded anchor rods. The length of the anchor holes 6 is greater than the length of the adjustment hole 5, and the locking member is located between the anchor holes 6.

[0030] Anchoring hole 6 is a Φ50mm×150mm long Q355B steel pipe (wall thickness 5mm), which is perpendicular to the outer wall of steel arch frame 101 during welding, with a spacing of 500mm; adjustment hole 5 is 30mm long, and anchoring hole 6 is 150mm long to ensure structural strength; locking screw 202 is located in the middle of adjacent anchoring holes 6 to avoid interference with anchor rod.

[0031] During the operation, the workers first insert the pre-embedded anchor rods into the anchor holes 6 and drive the arched steel arch support 1 into the surrounding rock of the tunnel. The locking parts fix the steel mesh 3 between the anchor holes 6 to ensure that there is no positional conflict between the anchor rods and the locking parts, and that the support structure is subjected to uniform stress to avoid local stress concentration that could cause deformation of the steel arch support 101.

[0032] In one embodiment of the present invention, the locking component includes a locking screw 202 slidably disposed in the corresponding adjustment hole 5. The end of the locking screw 202 slides through the steel arch frame 101, the steel mesh 3, and the locking washer 201 in sequence, and the end of the locking screw 202 is threadedly connected to a locking nut 203.

[0033] The locking screw 202 is made of 40Cr heat-treated steel (HRC28-32), and the head engages with the adjustment hole 5 with a clearance of 0.2mm, allowing for smooth sliding. The locking nut 203 is made of M1445# steel hot-dip galvanized (corrosion resistant), and its fit with the screw is 6g / 6H.

[0034] During operation, the worker first slides the locking screw 202 along the adjustment hole 5 to the target position according to the laying position of the steel mesh 3. The end of the screw passes through the steel arch frame 101, the steel mesh 3, and the locking washer 201 in sequence, and then tightens the locking nut 203. The sliding adjustment design allows the fixed position of the steel mesh 3 to be finely adjusted by ±15mm, which can accommodate the laying deviation of the steel mesh 3 without cutting the steel mesh 3 or modifying the steel arch frame 101.

[0035] As attached Figure 1 To be continued Figure 3 As shown: In one embodiment of this utility model, the locking washer 201 is provided with anti-slip teeth on the side facing the steel arch frame 101, and a spring washer is provided between the locking nut 203 and the locking washer 201.

[0036] The anti-slip teeth are triangular teeth with a height of 1mm and a spacing of 2mm, and the coefficient of friction is ≥0.8 when in contact with the side wall of the steel arch frame 101; the spring washers are of GB / T93-1987 14mm specification (elastic deformation 0.5-1mm) to ensure that the nuts are not loose after being tightened.

[0037] During operation, the workers first tighten the locking nut 203, and the spring washer is compressed to generate pre-tightening force. The anti-slip teeth are embedded in the small indentations on the side wall of the steel arch frame 101. The double anti-loosening design can resist the vibration of tunnel construction, prevent the steel mesh 3 from loosening after it is fixed, and ensure the long-term stability of the support structure.

[0038] As attached Figure 1 To be continued Figure 3 As shown: In one embodiment of this utility model, the connecting ear plate 102 is provided with a plurality of positioning holes 7 along its length direction, and the steel arch frame 101 is provided with a plurality of connecting holes that cooperate with the positioning holes 7. When adjacent steel arch frames 101 are spliced, the corresponding positioning holes 7 are aligned with the connecting holes.

[0039] Positioning hole 7 is a Φ20mm round hole (50mm spacing), and connecting hole is a Φ18mm round hole (located between positioning holes 7); when adjacent steel arch frames 101 are spliced, after positioning holes 7 are aligned, insert Φ19.8mm×120mm long 40Cr positioning pins with a positioning accuracy of ±2mm.

[0040] During operation, the workers first assemble the steel arch frame 101: align the connecting lugs 102 of adjacent steel arch frames 101, insert positioning pins to ensure that the positioning holes 7 and connecting holes are precisely aligned, and avoid misalignment during assembly; the positioning pins guide the subsequent installation of fasteners 4, improving the efficiency and accuracy of assembly, and ensuring that the overall curvature of the arc-shaped steel arch support 1 meets the design requirements.

[0041] As attached Figure 1 To be continued Figure 3As shown: In one embodiment of this utility model, a fastener 4 is provided in the connecting hole. The fastener 4 is located in the corresponding positioning hole 7 and is used to fix the adjacent steel arch frame 101. The fastener 4 is a high-strength bolt.

[0042] Fastener 4 is an M16×808.8 grade high-strength bolt (tensile strength ≥800MPa), with matching nuts and flat washers; each set of connecting ear plates has 1022 fasteners 4, symmetrically distributed on both sides of the positioning hole 7, with a tightening torque of 80-100N・m.

[0043] During operation, the workers first insert the fastener 4 into the connecting hole under the guidance of the positioning pin, and then put on the flat washer and tighten the nut in sequence; symmetrical tightening ensures that the connecting ear plate 102 is subjected to uniform force, and the shear strength of the splice is ≥150MPa, which can resist the lateral pressure of the surrounding rock of the tunnel and prevent the steel arch frame 101 from cracking.

[0044] As attached Figure 1 To be continued Figure 2 As shown: In one embodiment of this utility model, the edge of the steel mesh 3 is provided with a reinforcing frame, and the reinforcing frame is welded and fixed to the mesh steel bars of the steel mesh 3.

[0045] The reinforcing frame is made of Φ12mm HRB400 threaded steel (yield strength ≥400MPa), and is double-sided welded to the mesh reinforcement of steel mesh 3 (weld length ≥100mm, weld leg height 5mm); the reinforcing frame increases the bending strength of the edge of steel mesh 3 by 40%, and avoids edge deformation during installation.

[0046] During the work, the workers first lay the steel mesh 3. The reinforcing frame can be directly placed on the steel arch frame 101 or the reinforcing frame of the adjacent steel mesh 3. The overlap is fixed by the adjustable fixing component 2. The reinforcing frame ensures that the edge of the steel mesh 3 does not sag. When spraying concrete, the position of the steel mesh 3 is stable, which improves the overall integrity of the support structure.

[0047] In one embodiment of the present invention, a wear-resistant bushing is provided on the inner edge of the adjustment hole 5, and the wear-resistant bushing is embedded in the adjustment hole 5 by interference fit.

[0048] The wear-resistant bushing is made of 2mm thick brass (hardness HB100-120, wear resistance is better than steel), with an inner diameter of 15mm (0.2mm clearance with locking screw 202), and an interference fit of 0.05mm to ensure a firm embedding; the bushing surface is polished to Ra≤0.8μm to reduce the sliding resistance of the screw.

[0049] During operation, the operator first slides the locking screw 202 to adjust the position. The wear-resistant bushing isolates the screw from the steel arch frame 101, preventing burrs from forming on the edge of the adjustment hole 5 due to friction. The bushing is replaceable, and after long-term use, only the bushing needs to be replaced to restore the adjustment function, extend the service life of the steel arch frame 101, and reduce maintenance costs.

[0050] Working principle: According to the tunnel cross-section dimensions, workers transport several steel arch frames 101 to the construction face. First, they align the connecting ear plates 102 of adjacent steel arch frames 101 and insert positioning pins to make the positioning holes 7 and connecting holes precisely aligned. Then, they insert M16×808.8 grade high-strength bolts 4, put on flat washers, and tighten the nuts symmetrically (torque 80-100N・m) to complete the splicing of a single arc-shaped steel arch support 1. Multiple arc-shaped steel arch supports are assembled in sequence according to the design spacing (usually 500-800mm) to form an overall skeleton.

[0051] Insert the pre-embedded anchor rod (Φ22mm×2.5-3m long) into the anchor hole 6 on the outside of the steel arch frame 101, and use an anchor rod drilling machine to drive the anchor rod into the surrounding rock of the tunnel (anchoring depth ≥2m) to fix the arc-shaped steel arch support 1 on the surrounding rock; check the verticality and spacing of the support, and finely adjust the length (±100mm) through the expansion joints (inner sleeve and outer sleeve) at both ends of the steel arch frame 101 to ensure that the support is completely fitted with the tunnel section.

[0052] Lay the reinforcing mesh 3 from one side of the tunnel to the other. The reinforcing frame of the reinforcing mesh 3 overlaps the steel arch frame 101 or the reinforcing frame of the adjacent reinforcing mesh 3 (overlap length ≥ 200 mm). Take out the locking screw 202 of the adjustable fixing component 2, insert its head into the adjustment hole 5 of the steel arch frame 101, and slide it along the adjustment hole 5 to the mesh hole position of the reinforcing mesh 3, ensuring that the end of the screw can pass through the mesh hole. Pass the screw through the steel arch frame 101, the reinforcing mesh 3, and the locking washer 201 in sequence (anti-slip teeth facing the steel arch frame 101), and tighten the M14 locking nut 203. The spring washer is compressed to generate preload, and the anti-slip teeth are embedded in the side wall of the steel arch frame 101 to prevent loosening.

[0053] After confirming that the reinforcing mesh 3 and the arched steel arch support 1 are firmly fixed, start the concrete spraying machine to spray concrete (thickness ≥100mm) onto the surface of the support structure. Use isolation pads to ensure a 30mm protective layer between the reinforcing mesh 3 and the steel arch support 101. After construction, conduct regular inspections. If the position of the reinforcing mesh 3 needs to be adjusted, loosen the locking nut 203, slide the locking screw 202 to the target position, and then tighten it again. When the wear-resistant bushing in the adjustment hole 5 is severely worn, the steel arch support 101 can be removed and the bushing replaced to ensure long-term adjustment function.

[0054] The foregoing description only illustrates certain exemplary embodiments of the present invention. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. An adjustable initial support device for mined tunnels, characterized in that: It includes a steel mesh (3), several arc-shaped steel arch supports (1), and an adjustable fixing component (2) for connecting the arc-shaped steel arch supports (1) and the steel mesh (3). The arc-shaped steel arch support (1) includes several steel arch frames (101) that are connected end to end and spliced ​​together. Several sets of connecting ear plates (102) are provided at both ends of the steel arch frame (101). Several adjustment holes (5) are opened on the side wall of the steel arch frame (101) along its length direction. The length of the adjustment hole (5) is greater than the mesh diameter of the steel mesh (3). The adjustable fixing component (2) includes a locking shim (201), on which a plurality of locking elements are provided. The locking elements are respectively disposed in the corresponding adjustment holes (5) for locking the steel mesh (3).

2. The adjustable initial support device for mined tunnels according to claim 1, characterized in that: The outer sidewall of the steel arch frame (101) is arc-shaped, and a number of anchor holes (6) are provided on the outer sidewall of the steel arch frame (101). The anchor holes (6) are used to connect with the pre-embedded anchor rods. The length of the anchor holes (6) is greater than the length of the adjustment holes (5). The locking member is located inside the anchor holes (6).

3. The adjustable initial support device for mined tunnels according to claim 1, characterized in that: The locking component includes a locking screw (202) that is slidably disposed in the corresponding adjustment hole (5). The end of the locking screw (202) slides through the steel arch frame (101), the steel mesh (3), and the locking washer (201) in sequence, and the end of the locking screw (202) is threadedly connected to a locking nut (203).

4. The adjustable initial support device for mined tunnels according to claim 3, characterized in that: The locking washer (201) is provided with anti-slip teeth on the side facing the steel arch frame (101), and a spring washer is provided between the locking nut (203) and the locking washer (201).

5. The adjustable initial support device for mined tunnels according to claim 1, characterized in that: The connecting ear plate (102) has several positioning holes (7) along its length direction, and the steel arch frame (101) has several connecting holes that cooperate with the positioning holes (7). When adjacent steel arch frames (101) are spliced, the corresponding positioning holes (7) are aligned with the connecting holes.

6. The adjustable initial support device for mined tunnels according to claim 5, characterized in that: A fastener (4) is provided in the connection hole. The fastener (4) is located in the corresponding positioning hole (7) and is used to fix the adjacent steel arch frame (101). The fastener (4) is a high-strength bolt.

7. The adjustable initial support device for mined tunnels according to claim 1, characterized in that: The edge of the steel mesh (3) is provided with a reinforcing frame, which is welded and fixed to the mesh steel bars of the steel mesh (3).

8. The adjustable initial support device for mined tunnels according to claim 1, characterized in that: The inner edge of the adjustment hole (5) is provided with a wear-resistant bushing, which is embedded in the adjustment hole (5) by interference fit.

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