A tunnel construction method

Abstract

The present invention discloses a tunnel construction method, which includes the steps of: manually excavating to form a front-section tunnel, and providing primary support on the inner wall of the front-section tunnel; constructing concrete guide platforms on both sides of the arch bottom of the front-section tunnel; installing a launching pad at the front end of the front-section tunnel, aligning the launching pad with the concrete guide platforms or making the launching pad higher than the concrete guide platforms, assembling a shield machine on the launching pad, and installing a reaction frame on the side of the launching pad away from the front-section tunnel; the shield machine advances along the concrete guide platforms to the rear end of the front-section tunnel, and segments are spliced between the shield machine and the reaction frame; a sealing part is constructed between the segments behind the shield machine and the primary support to form a backfill space; the bottom layer of the backfill space is filled backward from the sealing part towards the front end of the front-section tunnel; the arch waist layers on both sides of the backfill space are filled forward; the top layer of the backfill space is filled backward. This tunnel construction method can avoid radial displacement of the segments during the filling process, avoid misalignment, damage, and water leakage between the spliced segments, improving both the construction quality and the construction efficiency.

Description

Technical Field

[0001] The present invention relates to the technical field of measuring instruments, and in particular to a tunnel construction method. Background Art

[0002] During subway tunnel construction, due to the variability of urban engineering geology, simple shield methods or simple mining methods (manual excavation) no longer meet current requirements. To minimize construction risks, mining methods are often used for excavation and initial support, with the shield machine advancing the assembled segments through the tunnel without load. Previously, the gaps between the initial support and the shield segment wall were often filled with blown-in pea gravel and simultaneous grouting. This method has low construction efficiency and poor segment quality, resulting in frequent segment misalignment, damage, and water leakage. Summary of the Invention

[0003] The technical problem to be solved by the present invention is to overcome the shortcomings of the existing technology and provide a tunnel construction method that can avoid radial displacement of the pipe segments during the filling process, avoid misalignment, damage, and water leakage between the spliced pipe segments, thereby improving both construction quality and construction efficiency.

[0004] In order to solve the above technical problems, the present invention adopts the following technical solutions:

[0005] A tunnel construction method comprises the following steps:

[0006] S1: Manual excavation forms the front tunnel section, and initial support is set up on the inner wall of the front tunnel section;

[0007] S2: Concrete guide platforms are constructed on both sides of the arch bottom of the front tunnel, extending along the axial direction of the front tunnel, with one end of the concrete guide platform extending to the front end of the front tunnel and the other end being spaced a predetermined distance from the rear end of the front tunnel;

[0008] S3: Install the starting platform at the front shield starting position of the front tunnel, aligning the starting platform with the concrete guide platform or making it higher than the concrete guide platform. Then assemble the shield machine on the starting platform and install the reaction frame on the side of the starting platform away from the front tunnel.

[0009] S4: The shield machine moves forward along the concrete guide platform until it reaches the rear end of the front tunnel and splices pipe segments between the shield machine and the reaction frame;

[0010] S5: Construct a plugging section between the segments behind the shield machine and the primary support, so that the segments and the primary support form a backfill space in the gap area between the plugging section and the front face of the front tunnel;

[0011] S6. Backfill the bottom layer of the backfill space by retreating from the plugging part towards the front end of the front-section tunnel; then, advance from the front end of the front-section tunnel towards the plugging part to fill the arch waist layers on both sides of the backfill space; finally, backfill the top layer of the backfill space by retreating from the plugging part towards the front end of the front-section tunnel.

[0012] As a further improvement of the above technical solution:

[0013] In S6, the arch waist layers on both sides of the backfill space are filled simultaneously.

[0014] In S6, the backfill space is filled with concrete.

[0015] In S5, the plugging part is formed by bricklaying.

[0016] In S4, the shield machine moves forward intermittently to splice the segments one by one until a whole pipe body coaxial with the front-section tunnel is formed in the front-section tunnel.

[0017] After the shield machine splices a segment, it separates from the segment, then moves forward a distance of one segment, and then splices the next segment. Before the shield machine separates from the segment, a bottom pad is set under the segment to keep the segment coaxial with the front-section tunnel.

[0018] The segments are spliced with staggered joints one by one.

[0019] In S6, after the backfill of the backfill space, void detection is carried out. For the non-compact parts, fixed-point supplementary secondary grouting is carried out through the reserved holes in the segments.

[0020] The predetermined distance in S2 is 1 m.

[0021] The tunnel construction method further includes step S7: After the filling of the backfill space is completed, the shield machine advances and excavates the rear-section tunnel while moving forward.

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

[0023] For the tunnel construction method of the present invention, concrete guide platforms are constructed on both sides of the arch bottom of the front-section tunnel respectively, and the concrete guide platforms extend along the axial direction of the front-section tunnel. The top surfaces of the two concrete guide platforms are symmetrical arc surfaces, and the centers of the arc surfaces coincide with the design axis of the front-section tunnel, which is convenient for the shield machine to push forward along the design axis. The other end of the concrete guide platform is spaced from the rear end of the front-section tunnel by a predetermined distance, which is convenient for the cutter head of the shield machine to be located within the interval of the predetermined distance and rotate smoothly for excavation construction after the shield machine pushes forward to the rear end of the front-section tunnel. For the backfill space between the outer wall of the segment and the initial support, a three-stage filling method of first retreating to fill the bottom layer, then advancing to fill the arch waist layer, and finally retreating to fill the top layer is adopted, which avoids the radial offset of the segment during the filling process, thus avoiding the step difference, damage, and water leakage between the spliced segments, and improving both the construction quality and the construction efficiency.

[0024] In the tunnel construction method of the present invention, the haunch layers on both sides of the backfill space are filled simultaneously. In this way, the segment is kept in place, avoiding lateral displacement of the segment caused by extrusion to the other side during unilateral backfilling.

[0025] In the tunnel construction method of the present invention, the front section of the tunnel is excavated manually, and the rear section of the tunnel is excavated by a shield machine. By combining manual excavation and shield machine excavation, the adaptability to different geological conditions is improved. For example, manual excavation is used for harder geological conditions, and the shield machine is used for softer geological conditions. Thereby, the construction progress is improved and the construction safety is ensured. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 is a flow chart of the tunnel construction method of the present invention.

[0027] Figure 2 is a schematic structural view of the shield machine of the tunnel construction method of the present invention located at the front end of the front section of the tunnel.

[0028] Figure 3 is a schematic structural view of the shield machine of the tunnel construction method of the present invention located at the rear end of the front section of the tunnel.

[0029] Figure 4 is a sectional view of the front section of the tunnel of the tunnel construction method of the present invention without filling.

[0030] Figure 5 is a sectional view of the front section of the tunnel of the tunnel construction method of the present invention with filling.

[0031] Each label in the figure represents:

[0032] 1. Front section of the tunnel; 2. Initial support; 3. Concrete guide platform; 31. Launching pad; 4. Shield machine; 5. Reaction frame; 6. Segment; 61. Bottom pad; 7. Sealing part; 8. Backfill space; 9. Bottom layer; 91. Haunch layer; 92. Top layer. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0033] The present invention will be further described in detail below with reference to the accompanying drawings of the specification and specific embodiments.

[0034] As shown in the present disclosure and the claims, unless the context clearly indicates otherwise, words such as "a", "an", "one", and / or "the" are not specifically singular and may also include the plural. The terms "first", "second", and similar terms used in the present disclosure do not denote any order, quantity, or importance, but are only used to distinguish different components. Similarly, words such as "comprising" or "including" mean that the elements or items appearing before this word cover the elements or items listed after this word and their equivalents, without excluding other elements or items. The terms "connected" or "coupled" and the like are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect.

[0035] Figures 1 to 5 An embodiment of the tunnel construction method of the present invention is shown. The tunnel construction method includes the following steps:

[0036] S1: Manually excavate to form the front-section tunnel 1, and set the initial support 2 on the inner wall of the front-section tunnel 1;

[0037] S2: Construct concrete guide platforms 3 on both sides of the arch bottom of the front-section tunnel 1 respectively, so that the concrete guide platforms 3 extend along the axial direction of the front-section tunnel 1, and one end of the concrete guide platforms 3 extends to the front end of the front-section tunnel 1, and the other end is spaced a predetermined distance from the rear end of the front-section tunnel 1;

[0038] S3: Install a launching pad 31 at the shield launching position at the front end of the front-section tunnel 1, so that the launching pad 31 is aligned with the concrete guide platform 3 or higher than the concrete guide platform 3, then assemble a shield machine 4 on the launching pad 31, and install a reaction frame 5 on the side of the launching pad 31 away from the front-section tunnel 1, as Figure 2 shown;

[0039] S4: The shield machine 4 advances along the concrete guide platform 3 until it reaches the rear end of the front-section tunnel 1, and segments 6 are spliced between the shield machine 4 and the reaction frame 5, as Figure 3 shown;

[0040] S5: Construct a sealing part 7 between the segments 6 behind the shield machine 4 and the initial support 2, so that a backfill space 8 is formed in the interval area between the segments 6 and the initial support 2 between the sealing part 7 and the front end face of the front-section tunnel 1, as Figure 3 and Figure 4 shown;

[0041] S6. Retract from the sealing part 7 towards the front end direction of the front-section tunnel 1 to fill the bottom layer 9 of the backfill space 8; then advance from the front end of the front-section tunnel 1 towards the sealing part 7 to fill the arch waist layers 91 on both sides of the backfill space 8; finally, retract from the sealing part 7 towards the front end direction of the front-section tunnel 1 to fill the top layer 92 of the backfill space 8, as Figure 5 shown.

[0042] This tunnel construction method constructs concrete guide platforms 3 on both sides of the arch bottom of the front tunnel 1, extending axially along the front tunnel 1. The top surfaces of the two concrete guide platforms 3 are symmetrical arc surfaces, with the centers of the arc surfaces coinciding with the design axis of the front tunnel 1, facilitating the tunnel boring machine 4 to push along the design axis. The other ends of the concrete guide platforms 3 are spaced a predetermined distance from the rear end of the front tunnel 1. This allows the shield machine 4 to be positioned within the predetermined distance after pushing the shield machine 4 to the rear end of the front tunnel 1, allowing it to rotate smoothly and carry out tunneling. The backfill space 8 between the outer wall of the segment 6 and the initial support 2 is filled in three stages: first, backward filling the bottom layer 9, then forward filling the arch waist layer 91, and finally, backward filling the top layer 92. This prevents radial displacement of the segment 6 during the filling process, thereby preventing misalignment, damage, and water leakage between the spliced segments 6, thereby improving both construction quality and efficiency.

[0043] In this embodiment, in S6, the haunches 91 on both sides of the backfill space 8 are filled simultaneously. This keeps the segments 6 in place and prevents the segments 6 from being squeezed toward the other side and shifted laterally when backfilling on one side.

[0044] In this embodiment, in S6, the backfill space 8 is filled with concrete. Specifically, the backfill space 8 is filled with crushed stone concrete, and after filling, it is formed at the same time as the front tunnel 1.

[0045] In this embodiment, in S5, the blocking portion 7 is formed by brickwork. The radial spacing between the segment 6 and the primary support 2 is between 1m and 1.5m, which is convenient for brickwork construction and has low cost.

[0046] In this embodiment, in S4, the shield machine 4 moves forward intermittently, so that the segments 6 are spliced one by one, until a structure as shown in FIG. Figure 3 The entire pipe shown is coaxial with the front tunnel 1.

[0047] In this embodiment, after the shield machine 4 splices a segment 6, it separates from the segment 6, moves forward a distance of one segment 6, and then splices the next segment 6. Before the shield machine 4 separates from the segment 6, a bottom pad 61 is set under the segment 6 to keep the segment 6 coaxial with the front tunnel 1.

[0048] In this embodiment, the segments 6 are spliced one by one with staggered seams, providing a counter-supporting force for the shield machine 4 to advance.

[0049] In this embodiment, in S6, after the backfill space 8 is backfilled, a cavity detection is performed, and secondary grouting is performed at designated locations through the reserved holes in the pipe segments 6 to further improve the construction quality.

[0050] In this embodiment, the predetermined distance in S2 is 1 m.

[0051] In this embodiment, the tunnel construction method further includes step S7: after the backfill space 8 is filled, the shield machine 4 advances while excavating the rear section of the tunnel. In this way, the front section of the tunnel 1 is excavated manually, and the rear section of the tunnel is excavated by the shield machine 4. By combining manual excavation and excavation by the shield machine 4, the adaptability to different geological conditions is improved. For example, manual excavation is used for harder geological conditions, and the shield machine 4 is used for softer geological conditions. Thereby, the construction progress is improved and the construction safety is ensured.

[0052] In this embodiment, in S3, the launching pad 31 is made 10 - 20 mm higher than the concrete guide table 3, which facilitates the shield machine 4 to step onto the concrete guide table 3.

[0053] The segment 6 is coaxial with the shield machine 4 and has a diameter smaller than that of the shield machine 4.

[0054] In this embodiment, in S6, the thickness of the bottom layer 9 is set such that the upward buoyancy on the segment 6 is less than the weight of the segment 6. For example, the bottom layer 9 is tangent to the bottom of the segment 6. In this way, the segment 6 will not move upward due to the excessive thickness of the bottom layer 9.

[0055] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make many possible changes and modifications to the technical solution of the present invention, or modify it into an equivalent embodiment with equivalent changes, without departing from the scope of the technical solution of the present invention. Therefore, any simple modification, equivalent change and modification made to the above embodiments according to the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the scope of protection of the technical solution of the present invention.

Claims

1. A tunnel construction method, characterized in that: The following steps are involved: S1: artificially excavating a front tunnel (1) and setting up initial support (2) on the inner wall of the front tunnel (1); S2: Concrete guide platforms (3) are constructed on both sides of the arch bottom of the front tunnel (1), so that the concrete guide platforms (3) extend along the axial direction of the front tunnel (1), and one end of the concrete guide platform (3) extends to the front end of the front tunnel (1), and the other end is spaced a predetermined distance from the rear end of the front tunnel (1); S3: Install a starting platform (31) at the front shield starting position of the front tunnel (1), so that the starting platform (31) is aligned with or higher than the concrete guide platform (3), then assemble the shield machine (4) on the starting platform (31), and install a reaction frame (5) on the side of the starting platform (31) away from the front tunnel (1); S4: The shield machine (4) moves forward along the concrete guide platform (3) until it reaches the rear end of the front tunnel (1), and a pipe segment (6) is spliced between the shield machine (4) and the reaction frame (5); S5: constructing a blocking portion (7) between the rear segment (6) of the shield machine (4) and the initial support (2), so that the segment (6) and the initial support (2) form a backfill space (8) in the interval area between the blocking portion (7) and the front end face of the front tunnel (1); S6, the blocking portion (7) moves backwards toward the front end of the front tunnel (1) to fill the bottom layer (9) of the backfill space (8); then, the front end of the front tunnel (1) moves forward toward the blocking portion (7) to fill the waist layers (91) on both sides of the backfill space (8); finally, the blocking portion (7) moves backwards toward the front end of the front tunnel (1) to fill the top layer (92) of the backfill space (8).

2. The tunnel construction method according to claim 1, characterized in that: In the step S6, the haunch layers (91) on both sides of the backfill space (8) are filled simultaneously.

3. The tunnel construction method according to claim 1, characterized in that: In S6, the backfill space (8) is filled with concrete.

4. The tunnel construction method according to claim 1, characterized in that: In the above-mentioned S5, the blocking portion (7) is formed by brickwork.

5. The tunnel construction method according to claim 1, characterized in that: In the above-mentioned S4, the shield machine (4) moves forward intermittently, so that the pipe segments (6) are spliced one by one until a whole pipe body coaxial with the front tunnel (1) is formed in the front tunnel (1).

6. The tunnel construction method according to claim 5, characterized in that: After the shield machine (4) splices a pipe segment (6), it separates from the pipe segment (6), moves forward a distance of a pipe segment (6), and then splices the next pipe segment (6). Before the shield machine (4) separates from the pipe segment (6), a bottom pad (61) is provided below the pipe segment (6) to keep the pipe segment (6) coaxial with the front tunnel (1).

7. The tunnel construction method according to claim 5, characterized in that: The pipe segments (6) are spliced one by one with staggered seams.

8. The tunnel construction method according to claim 1, characterized in that: In said S6, after the backfill space (8) is backfilled, a cavity detection is performed, and secondary grouting is performed at fixed points through the reserved holes in the pipe segment (6) at the uncompacted areas.

9. The tunnel construction method according to claim 1, characterized in that: The predetermined distance in S2 is 1 m.

10. The tunnel construction method according to any one of claims 1 to 9, characterized in that: The tunnel construction method further comprises step S7: after the backfill space (8) is filled, the shield machine (4) is used to excavate the rear section of the tunnel while moving forward.

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