In-situ expansion construction method for multi-arch tunnel with existing lining

Abstract

The present application relates to a method for expanding a multi-arch tunnel in situ using existing lining, designing an expanded tunnel excavation profile; backfilling the lower half of the tunnel; removing the existing arch top lining on the outside of the tunnel, excavating the arch top rock-soil body and applying primary support; removing the backfill soil body on the outside of the tunnel, removing the side wall of the outside tunnel, excavating the rock-soil body behind the side wall and applying primary support; removing the existing arch top lining on the inside of the tunnel, excavating the arch top surrounding rock and applying primary support on the inside; removing the backfill soil body on the inside of the tunnel; removing the remaining lining structure and steel support, excavating to the position of the tunnel design contour line and applying a inverted arch, using the existing central partition wall lining as part of the primary support of the newly built tunnel, so that the primary support forms a closed loop; applying the lower half of the secondary lining of the expanded tunnel; applying the upper half of the secondary lining of the expanded tunnel. The existing tunnel lining provides temporary support for the expanded tunnel, part of the existing lining is retained as permanent lining of the expanded tunnel, and the role of the existing lining is fully played.

Description

Technical fields:

[0002] This invention relates to a method for in-situ expansion of multi-arch tunnels utilizing existing lining. Background technology:

[0004] With the rapid growth of the national economy and transportation demand, many highways or municipal roads built in the early stages are facing the challenge of expansion. Compared with expanding new lines, expanding existing lines in situ has advantages such as smooth alignment and saving construction land, and is increasingly being used in urban environments where construction land is limited.

[0005] Compared to in-situ expansion of roads or bridges, in-situ expansion of tunnels presents more complex engineering challenges. Currently, the design and construction schemes proposed for in-situ tunnel expansion mainly focus on single-bore tunnels. Patent CN102121385A provides a construction method for expanding an existing single-bore tunnel into a double-arch tunnel; patent CN103821523A provides a method for expanding an existing single-bore two-lane tunnel into a single-bore four-lane tunnel; and patent CN115653618A proposes a method for expanding an existing small-section multi-arch tunnel into a large-section single-bore tunnel.

[0006] High-grade municipal roads need to accommodate two-way traffic of motor vehicles and non-motor vehicles. Due to constraints of land use and early technology, multi-arch (usually four-arch) small-section tunnels are quite common in municipal road systems. However, the relevant technical research or engineering experience for in-situ expansion of such tunnels is still significantly immature. Summary of the Invention:

[0008] The purpose of this invention is to provide a method for in-situ expansion of multi-arch tunnels using existing linings.

[0009] To achieve the above objectives, the technical solution adopted by the present invention is: a method for in-situ expansion of a multi-arch tunnel utilizing existing lining, comprising the following steps:

[0010] (1) Based on the cross-sectional shape of the existing multi-arch tunnel and the design traffic volume requirements, determine the inner contour surface and excavation contour surface of the in-situ expansion tunnel.

[0011] (2) The lower half of the tunnel can be backfilled using the excavation slag generated from the previous cycle advance and the dismantled lining.

[0012] (3) Remove the lining of the outer arch of the existing continuous arch tunnel, excavate the rock and soil of the arch and construct the initial support, and at the same time use the temporary vertical bracing and the continuous arch partition wall to provide support for the subsequent excavation.

[0013] (4) Remove the backfill soil from the outer tunnel, demolish the outer tunnel sidewall, excavate the soil and rock behind the sidewall and construct the initial support;

[0014] (5) Remove the lining of the inner tunnel arch of the existing multi-arch tunnel, excavate the rock and soil of the arch and construct the inner initial support. The inner initial support is supported by the lining of the central partition wall of the existing multi-arch tunnel.

[0015] (6) Remove the backfill soil from the inner tunnel;

[0016] (7) Remove the remaining lining structure and steel support, excavate to the tunnel design outline and construct the invert arch, and use the existing central partition wall lining as part of the initial support of the new tunnel to form a closed loop.

[0017] (8) Construct the invert arch and secondary lining of the low sidewalls for the expanded tunnel;

[0018] (9) Construct the secondary lining of the arch waist, arch shoulder and arch top of the expanded tunnel.

[0019] Furthermore, in step (3), the outer arch of the tunnel is sprayed with anchors and the waist anchor rods are used as the initial support; the temporary vertical support is placed on the outer middle partition wall of the existing tunnel.

[0020] Furthermore, in step (4), the outer sidewall sprayed anchor support and foot locking anchor rods of the expanded tunnel are constructed as the initial support.

[0021] Furthermore, in step (5), the inner initial support is the inner arch sprayed anchor support, which is located on the central partition wall of the existing tunnel.

[0022] Compared with the prior art, the present invention has the following advantages: The present invention is reasonably designed, utilizing the existing tunnel lining to provide temporary support for the expanded tunnel, and retaining part of the existing lining as the permanent lining of the expanded tunnel, thus giving full play to the role of the existing lining; at the same time, the soil and rock mass generated from the removal of the lining and excavation can be used as the material for the backfilling construction of the expanded tunnel, effectively realizing the tunnel expansion construction and embodying the concept of green construction. Attached image description:

[0024] Figure 1 This is a schematic diagram of the cross-section of the in-situ expansion of the multi-arch tunnel in an embodiment of the present invention;

[0025] Figure 2 This is a schematic diagram of existing tunnel backfilling in an embodiment of the present invention;

[0026] Figure 3 This is a schematic diagram of the expansion of the outer arch portion in an embodiment of the present invention;

[0027] Figure 4 This is a schematic diagram of the expansion of the outer sidewall in an embodiment of the present invention;

[0028] Figure 5 This is a schematic diagram of the expansion of the inner arch portion in an embodiment of the present invention;

[0029] Figure 6 This is a schematic diagram of the removal of backfill soil from the inner tunnel in an embodiment of the present invention;

[0030] Figure 7 This is a schematic diagram of the expansion of the inverted arch portion in an embodiment of the present invention;

[0031] Figure 8 This is a schematic diagram of the lower half of the secondary lining construction in an embodiment of the present invention;

[0032] Figure 9 This is a schematic diagram of the construction of the upper secondary lining in an embodiment of the present invention.

[0033] In the picture:

[0034] 1-Existing tunnel lining; 11-Outer arch lining; 12-Outer sidewall lining; 13-Inner arch lining; 14-Central partition wall; 15-Outer partition wall; 16-Bottom invert arch; 2-Surrounding rock to be excavated; 3-Backfill soil of existing tunnel; 4-Initial support of expanded tunnel; 41-Outer arch sprayed anchor support; 42-Temporary vertical bracing; 43-Waist anchor bolt; 44-Outer sidewall sprayed anchor support; 45-Foot anchor bolt; 46-Inner arch sprayed anchor support; 47-Invert arch shotcrete support; 5-Secondary lining of expanded tunnel; 51-Lower secondary lining; 52-Upper secondary lining. Detailed implementation method:

[0036] The present invention will now be described in further detail with reference to the accompanying drawings and specific embodiments.

[0037] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0038] This invention discloses a method for in-situ expansion of a multi-arch tunnel utilizing existing lining, comprising the following steps:

[0039] (1) Based on the cross-sectional shape of the existing multi-arch tunnel and the design traffic volume requirements, determine the inner contour surface and excavation contour surface of the in-situ expansion tunnel.

[0040] (2) Backfill the lower half of the existing tunnel to maintain structural stability during subsequent construction; the excavation slag generated during the previous cycle advance and the dismantled lining can be used for backfilling;

[0041] (3) Remove the lining of the outer arch of the existing continuous arch tunnel, excavate the rock and soil of the arch and construct the initial support, and at the same time use the temporary vertical bracing and the continuous arch partition wall to provide support for the subsequent excavation.

[0042] (4) Remove the backfill soil from the outer tunnel, demolish the outer tunnel sidewall, excavate the soil and rock behind the sidewall and construct the initial support;

[0043] (5) Remove the lining of the inner tunnel arch of the existing multi-arch tunnel, excavate the rock and soil of the arch and construct the inner initial support. The inner initial support is supported by the lining of the central partition wall of the existing multi-arch tunnel.

[0044] (6) Remove the backfill soil from the inner tunnel;

[0045] (7) Remove the remaining lining structure and steel support, excavate to the tunnel design outline and construct the invert arch, and use the existing central partition wall lining as part of the initial support of the new tunnel to form a closed loop.

[0046] (8) Construct the invert arch and secondary lining of the low sidewalls for the expanded tunnel;

[0047] (9) Construct the secondary lining of the arch waist, arch shoulder and arch top of the expanded tunnel.

[0048] In this embodiment, the outer arch sprayed anchor support and waist locking foot anchor rods of the expanded tunnel are constructed as the initial support in step (3); the temporary vertical support is placed on the outer middle partition wall of the existing tunnel to ensure the safety of subsequent surrounding rock excavation and support.

[0049] In this embodiment, the outer sidewall sprayed anchor support and foot locking anchor rods of the expanded tunnel are used as the initial support in step (4).

[0050] In this embodiment, the inner initial support in step (5) is the inner arch sprayed anchor support, which is located on the central partition wall of the existing tunnel.

[0051] Example: Figure 1 As shown, the four-arch small-section tunnel is expanded in situ into a two-arch large-section tunnel to accommodate the traffic needs of both vehicular and non-vehicular vehicles. The specific construction steps are illustrated using the right half of the tunnel as an example; the construction steps for the left half are the same as for the right half. It should be noted that the attached drawings are only schematic diagrams to help illustrate the construction method of this invention and are not actual construction drawings. Therefore, only the necessary structures for each construction step are shown, and the shown or omitted parts are not limitations on actual construction. The specific construction steps are as follows:

[0052] 1) such as Figure 2 As shown: Backfill the existing tunnel with soil up to the arch waist to ensure stability and safety during lining removal, surrounding rock excavation, and support processes. The backfill can be made using excavated material from the previous cyclic advance and the removed lining.

[0053] 2) such as Figure 3 As shown: Remove the outer arch lining 11 of the existing tunnel, excavate the surrounding rock 2 to the predetermined outline; construct the outer arch sprayed anchor support 41 and waist locking foot anchor 43 of the expanded tunnel, and at the same time construct temporary vertical supports 42, which are placed on the outer middle partition wall 15 of the existing tunnel to ensure the safety of subsequent surrounding rock excavation and support.

[0054] 3) such as Figure 4 As shown: Remove the outer backfill soil 3, demolish the outer sidewall lining 12 of the existing tunnel, and excavate the surrounding rock 2 to the predetermined outline; at the same time, construct the outer sidewall shotcrete support 44 and the foot anchor bolt 45 of the expanded tunnel.

[0055] 4) such as Figure 5 As shown: the inner arch lining 13 of the existing tunnel is removed, and the surrounding rock 2 is excavated to the predetermined outline; at the same time, the inner arch sprayed anchor support 46 of the expanded tunnel is constructed and placed on the central partition wall 14 of the existing tunnel.

[0056] 5) such as Figure 6 As shown: Remove the inner backfill soil 3;

[0057] 6) For example Figure 7 As shown: Remove the temporary vertical support 42, the outer middle partition wall 15 and the bottom invert arch 16, and excavate the surrounding rock 2 to the predetermined outline; at the same time, construct the invert arch shotcrete support 47 to close the initial support system of the right-side expansion tunnel into a ring.

[0058] 7) For example Figure 8 As shown: the lower half 51 of the secondary lining of the expanded tunnel, namely the invert arch and the low sidewall;

[0059] 8) For example Figure 9 As shown: the upper part 52 of the secondary lining of the expanded tunnel, namely the arch waist, arch shoulder and arch top.

[0060] This invention provides a new solution for in-situ expansion of multi-arch tunnels, and its beneficial effects are as follows:

[0061] 1) This expansion construction method utilizes the existing tunnel lining to provide temporary support for the expanded tunnel, and some of the existing lining is retained as the permanent lining of the expanded tunnel, giving full play to the role of the existing lining;

[0062] 2) The soil and rock mass generated from the removal of the lining and excavation can be used as backfill material for the tunnel expansion construction, effectively realizing the tunnel expansion construction and embodying the concept of green construction.

[0063] If this invention discloses or relates to mutually fixedly connected components or structural parts, then, unless otherwise stated, a fixed connection can be understood as: a detachable fixed connection (e.g., using bolts or screws), or a non-detachable fixed connection (e.g., riveting, welding). Of course, mutually fixed connections can also be replaced by an integral structure (e.g., manufactured in one piece using a casting process) (except where it is obviously impossible to use an integral molding process).

[0064] In addition, unless otherwise stated, the terms used in any of the technical solutions disclosed in this invention to indicate positional relationships or shapes include states or shapes that are similar to, close to, or approximate with those states or shapes.

[0065] Any component provided by this invention can be assembled from multiple individual components or can be a single component manufactured by a one-piece molding process.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them; although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of the present invention or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solutions of the present invention, and all such modifications and substitutions should be covered within the scope of the technical solutions claimed in the present invention.

Claims

1. A method for in-situ expansion of a multi-arch tunnel utilizing existing lining, characterized in that: Includes the following steps: (1) Based on the cross-sectional shape of the existing multi-arch tunnel and the design traffic volume requirements, determine the inner contour surface and excavation contour surface of the in-situ expansion tunnel. (2) The lower half of the tunnel can be backfilled using the excavation slag generated from the previous cycle advance and the dismantled lining. (3) Remove the lining of the outer arch of the existing continuous arch tunnel, excavate the rock and soil of the arch and construct the initial support, and use temporary vertical bracing and continuous arch partition wall to provide support for subsequent excavation; construct the outer arch spray anchor support and waist locking foot anchor rod as the initial support for the expanded tunnel; the temporary vertical bracing is located on the outer middle partition wall of the existing tunnel. (4) Remove the backfill soil of the outer tunnel, demolish the outer tunnel sidewall, excavate the rock and soil behind the sidewall and construct the initial support; construct the outer sidewall sprayed anchor support and foot locking anchor rod as the initial support for the expanded tunnel. (5) Remove the lining of the inner arch of the existing multi-arch tunnel, excavate the rock and soil of the arch and construct the inner primary support. The inner primary support is supported by the lining of the central partition wall of the existing multi-arch tunnel. The inner primary support is the inner arch sprayed anchor support, which is located on the central partition wall of the existing tunnel. (6) Remove the backfill soil from the inner tunnel; (7) Remove the remaining lining structure and steel support, excavate to the tunnel design outline and construct the invert arch, and use the existing central partition wall lining as part of the initial support of the new tunnel to form a closed loop. (8) Construct the invert arch and secondary lining of the low sidewalls for the expanded tunnel; (9) Construct the secondary lining of the arch waist, arch shoulder and arch top of the expanded tunnel.

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