Receiving section variable cross-section reinforcing protection structure for shield-mining method tunnel butt joint

Abstract

The utility model discloses a receiving section variable cross-section reinforcing protection structure for shield-mining method tunnel butt joint, which comprises a cavern, a shield tunnel, a transition gradual change reinforcing body and a head blocking wall, the cavern is in radial butt joint with the shield tunnel, and the vault of the cavern is about 4m higher than the shield tunnel; the transition gradually-changed reinforcing body is formed by adopting a segmented retreating type wall back deep hole grouting process, the annular spacing of grouting holes is 2-2.5 m, the row spacing is 1 ring segment, slurry adopts cement-water glass double-liquid slurry, the reinforcing length is 10-15 ring segments, and the thickness is reduced ring by ring in the direction from the cavern to the tunnel; a C35 reinforced concrete head blocking wall with the thickness of 50 cm is arranged at the joint of the cavern and the tunnel lining, the C35 reinforced concrete head blocking wall and the end face of the receiving ring duct piece are welded and poured into a whole, and the length of the duct piece extending into the head blocking wall is controlled to be smaller than or equal to 20 cm; a 2cm-wide deformation joint and double water-stop belts (back-attached type and annular middle-buried type steel edge type) are arranged between the head blocking wall and the cavern, and the problems of stress concentration, leakage and tunnel settlement at the variable cross section of the receiving section are effectively solved through the synergistic effect of a transition gradual-change reinforcing body and the head blocking wall.

Description

Technical Field

[0001] This utility model relates to the field of shield tunnel construction technology, and in particular to a variable cross-section reinforcement and protection structure for the receiving section of a shield-mining method tunnel connection. Background Technology

[0002] In tunnel construction, a single tunneling method is often insufficient to adapt to varying geological conditions. While combining shield tunneling with mining methods to create tunnels in both directions can enhance the ability to traverse changing geological formations, it also presents challenges in settlement control due to differences in construction methods.

[0003] Furthermore, tunnel docking construction requires widening the receiving section of the mining method tunnel to reserve construction space for shield machine reception and dismantling. Due to differences in structural materials, construction sequence, and cross-sectional shape between the two methods, the docking area is prone to uncoordinated deformation, leading to uneven ground settlement. To achieve underground shield machine reception, the mining method tunnel needs to widen its cross-section to meet the shield machine reception space requirements. However, during the shield machine's entry into the mining method receiving section, the shield machine's own synchronous grouting cannot form a gradual reinforcement, resulting in stress concentration at the abrupt change in the cross-section between the receiving chamber and the shield tunnel, exacerbating the risk of ground instability. Existing technologies mostly use full-section grouting, which cannot effectively solve the problem of gradual stiffness transition in the variable cross-section section. The dynamic load during shield machine penetration can easily induce collapse in the weakly reinforced area. Therefore, sufficient reinforcement and protection measures are needed for the variable cross-section section to ensure the safe reception of the shield machine and reduce the impact on the surrounding environment. Utility Model Content

[0004] The purpose of this invention is to address the shortcomings of existing technologies by proposing a variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection. This structure can effectively reduce stress concentration at abrupt cross-section changes and the risk of uneven ground settlement, ensuring the safe reception of the shield machine.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection includes a cavern, a shield tunnel, a transitional reinforcement body, and a retaining wall. The cavern is radially connected to the shield tunnel, and the horseshoe-shaped cross-section of the cavern and the circular cross-section of the shield tunnel are connected at the variable cross-section of the receiving section. The cavern's vault is approximately 4 meters higher than the shield tunnel, and the transitional reinforcement body is arranged around the shield tunnel.

[0007] Preferably, the transitional solidification body is formed by a segmented, backward-retreating deep-hole grouting process using pre-reserved annular grouting holes within the tunnel segments. The circumferential spacing of the grouting holes is 2-2.5m, with a row spacing of 1 ring of tunnel segments. The grout is a cement-water glass dual-liquid grout. The length of the transitional solidification body ranges from 10-15 rings of tunnel segments outside the tunnel, and the thickness decreases ring by ring from the tunnel chamber towards the shield tunnel. The ground stress is gradually released as the solidification body passes through the tunnel segment.

[0008] Preferably, the retaining wall is set at the joint between the cavern lining and the shield tunnel lining. The retaining wall is 50cm thick and made of C35 reinforced concrete. Its vertical surface is protected by anchor mesh spraying, with 23cm thick C25 concrete sprayed on it. A6 steel mesh is used with a spacing of 25×25cm, and 3m long mortar anchors are installed with a spacing of 1.0×1.0m.

[0009] Preferably, a back-adhesive rubber waterstop and a circumferential embedded steel-edged rubber waterstop are provided at the connection end between the end wall and the cavern, and the waterproofing board of the end wall and the waterproofing board of the cavern are connected as a whole.

[0010] Preferably, a deformation joint with a width of 2cm is provided at the joint between the end wall and the cavern lining.

[0011] Preferably, the end face of the retaining wall lining and the receiving ring segment are welded and cast into a whole using HRB400 steel bars, and the length of the segment entering the thickness range of the retaining wall is controlled to not exceed 20cm. If the length of the segment entering the retaining wall exceeds 20cm, one ring segment can be reduced, and the cast-in-place section of the retaining wall can be extended to the shield tunnel section.

[0012] Compared with the prior art, the beneficial effects of this utility model are:

[0013] (1) By forming a transitional solidified body through segmented backward deep hole grouting, the stiffness between the cavern and the shield tunnel can be smoothly transitioned, effectively reducing the stress concentration phenomenon when the shield machine receives the tunnel and reducing the risk of segment cracking.

[0014] (2) A 50cm thick C35 reinforced concrete retaining wall is set at the joint between the cavern lining and the shield tunnel lining. The retaining wall and the end face of the segment are welded with steel bars and cast as a whole to form a rigid node, which makes up for the difference in cross-sectional shape between the cavern and the shield tunnel and avoids cracking or deformation at the variable cross-section joint due to local stress concentration.

[0015] (3) Limit the length of the tunnel segment entering the head wall (≤20cm) or extend the cast-in-place section to the shield tunnel by reducing the number of tunnel segment rings to ensure the integrity of the structure and avoid uneven stress caused by abrupt changes in cross section;

[0016] (4) Install a back-adhesive rubber waterstop and a circumferential embedded steel-edged rubber waterstop at the connection end between the end wall and the cavern, and connect the waterproofing board of the end wall and the waterproofing board of the cavern into a whole, providing double waterproof protection, eliminating weak links at the joint, and forming a continuous and leak-free channel. Attached Figure Description

[0017] To illustrate the technical solutions in the embodiments of the present invention or the prior art more specifically and intuitively, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0018] Figure 1 This is a schematic diagram of the structure proposed in this utility model;

[0019] Figure 2 for Figure 1 Enlarged view of part A in the middle;

[0020] Figure 3 for Figure 1 Enlarged view of part B in the middle.

[0021] In the diagram: 1-Cavity, 2-Shield tunnel, 3-Segment, 4-Grouting hole, 5-Transitional reinforcement body, 6-Head wall, 7-Mortar anchor, 8-Cavity lining, 9-Waterproof membrane, 10-Back-adhesive rubber waterstop, 11-Circumferential embedded steel-edged rubber waterstop, 12-Expansion joint. Detailed Implementation

[0022] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present utility model. Obviously, the described embodiments are only some embodiments of the present utility model, and not all embodiments.

[0023] Reference Figure 1-3 A variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection includes a cavern 1, a shield tunnel 2, a transitional reinforcement body 5, and a retaining wall 6. The cavern 1 is radially connected to the shield tunnel 2; the horseshoe-shaped cross-section of the cavern 1 connects to the circular cross-section of the shield tunnel 2 at the variable cross-section of the receiving section; the arch of the cavern 1 is approximately 4 meters higher than that of the shield tunnel 2; and the transitional reinforcement body 5 is arranged around the shield tunnel 2.

[0024] In this implementation plan, the transitional solidification body 5 is formed by a segmented retreating deep hole grouting process through the pre-reserved annular grouting holes 4 inside the segment 3. The circumferential spacing of the grouting holes is 2-2.5m, and the row spacing is 1 ring segment. The grout is a cement-water glass dual-liquid grout. The length of the transitional solidification body 5 is 10-15 ring segments outside the tunnel 1, and the thickness decreases ring by ring from the tunnel 1 towards the shield tunnel 2. The ground stress is gradually released when passing through the solidification body.

[0025] In this implementation plan, the retaining wall 6 is set at the joint between the cavern lining 8 and the shield tunnel lining. The retaining wall 6 is 50cm thick and made of C35 reinforced concrete. Its vertical surface is protected by anchor mesh spraying, with 23cm thick C25 concrete sprayed on it. A6 steel mesh is used with a spacing of 25×25cm. 3m long mortar anchor rods 7 are installed with a spacing of 1.0×1.0m.

[0026] During the initial support construction of the 6th facade of the retaining wall, two steel sections were installed 50cm above the outline of the shield tunnel lining for reinforcement. The steel sections used were I-beams of 20b, and two φ42 anchor pipes were installed at 2m intervals and fixed by welding with U-shaped steel bars. The two ends of the steel sections were welded to the initial support steel frame.

[0027] A back-adhesive rubber waterstop 10 and a circumferential embedded steel-edged rubber waterstop 11 are installed at the connection end between the end wall 6 and the cavern 1. The waterproofing plate 9 of the end wall 6 and the waterproofing plate 9 of the cavern 1 are connected as a whole.

[0028] In this implementation plan, an expansion joint 12, 2cm wide, is provided at the joint between the end wall 6 and the lining of the cavern 1.

[0029] The end face of the retaining wall 6 lining and the receiving ring segment 3 are welded and cast into a whole using HRB400 steel bars. The length of segment 3 entering the thickness range of the retaining wall 6 is controlled to not exceed 20cm. During construction, if the length of segment 3 entering the retaining wall 6 exceeds 20cm according to the actual arrangement of segment 3, one ring of segment 3 can be reduced, and the cast-in-place section of the retaining wall 6 can be extended to the shield tunnel section 2.

[0030] The above description is only a preferred embodiment of the present utility model, but the protection scope of the present utility model is not limited thereto. Any equivalent substitutions or changes made by those skilled in the art within the technical scope disclosed in the present utility model, based on the technical solution and the inventive concept of the present utility model, should be included within the protection scope of the present utility model.

Claims

1. A variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection, comprising a cavern (1), a shield tunnel (2), a transitional reinforcement body (5), and a retaining wall (6), characterized in that, The cavern (1) is radially connected to the shield tunnel (2). The horseshoe-shaped cross section of the cavern (1) and the circular cross section of the shield tunnel (2) are connected at the receiving section with a variable cross section. The arch of the cavern (1) is about 4m higher than the shield tunnel (2). The transitional solidification body (5) is set around the shield tunnel (2).

2. The variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection as described in claim 1, characterized in that, The transitional solidification body (5) is formed by a segmented backward deep hole grouting process through the pre-reserved annular grouting holes (4) in the segment (3). The circumferential spacing of the grouting holes is 2-2.5m, and the row spacing is 1 ring segment. The grout is cement-water glass double liquid grout. The length range of the transitional solidification body (5) is 10-15 ring segments outside the cavern (1). The thickness decreases ring by ring from the cavern (1) towards the shield tunnel (2). The ground stress is gradually released when passing through the solidification body.

3. The variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection as described in claim 1, characterized in that, The retaining wall (6) is set at the joint between the cavern lining (8) and the shield tunnel lining. The retaining wall (6) is 50cm thick and made of C35 reinforced concrete. Its vertical surface is protected by anchor mesh spraying, spraying 23cm thick C25 concrete, using A6 steel mesh with a spacing of 25×25cm, and 3m long mortar anchor rods (7) with a spacing of 1.0×1.0m.

4. A variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection as described in claim 1, characterized in that, The end of the retaining wall (6) connected to the cavern (1) is provided with a back-adhesive rubber waterstop (10) and a circumferential embedded steel-edged rubber waterstop (11), and the waterproofing plate (9) of the retaining wall (6) and the waterproofing plate (9) of the cavern (1) are connected as a whole.

5. A variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection as described in claim 1, characterized in that, A deformation joint (12) with a width of 2cm is provided at the joint between the end wall (6) and the lining of the cave (1).

6. A variable cross-section reinforcement and protection structure for the receiving section of a shield-mining tunnel connection as described in claim 1, characterized in that, The end face of the retaining wall (6) and the receiving ring segment (3) are welded and cast together with HRB400 steel bars. The length of the segment (3) entering the thickness range of the retaining wall (6) is controlled to not exceed 20cm. If the length of the segment (3) entering the retaining wall (6) exceeds 20cm, one ring segment (3) can be reduced and the cast-in-place section of the retaining wall (6) can be extended to the shield tunnel (2) section.

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