Open-cut tunnel spanning existing culvert structure and construction method thereof

Abstract

The present invention discloses an open-cut tunnel structure that crosses over an existing culvert and a construction method thereof. The open-cut tunnel structure that crosses over an existing culvert includes: an existing culvert; a tunnel structure that is obliquely arranged above the existing culvert; a plurality of pile foundations that support the tunnel structure; and a protective structure that includes a slope module and a support module. The slope module and the support module cooperate to define the range of the tunnel structure. The slope modules are respectively arranged at two intersections of the tunnel structure and the existing culvert, and the support modules are adjacent to the remaining positions within the range where the slope modules are arranged. By locally adopting the slope module and cooperating with the support module to form a foundation pit type, the scale of the foundation pit is reduced, and the structure has a good ability to control surface deformation. By having the pile foundation bear the vertical load of the tunnel structure, the existing culvert and the newly built tunnel are each independent force-bearing systems, thereby avoiding mutual influence between the two and ensuring the safety of the existing culvert and the newly built tunnel during the long-term use period after completion.

Description

Technical Field

[0001] The present invention relates to the technical field of tunnel construction, and in particular to an open-cut tunnel spanning an existing culvert structure and a construction method thereof. Background Art

[0002] During urban transportation construction, tunnels inevitably cross existing underground culverts. This, coupled with the complex urban environment and the presence of sensitive structures, roads, and pipelines, often presents challenges and key points in project implementation. Renovating existing culverts inevitably complicates the construction process, increases the workload, and prolongs the construction period. Summary of the Invention

[0003] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention proposes an open-cut tunnel that spans over an existing culvert structure. This avoids the need for modification of the existing culvert, simplifies the construction process, does not affect the normal use of the existing culvert, and ensures the safety of both the existing culvert and the newly constructed tunnel structure during construction and post-completion use.

[0004] The present invention also provides a construction method for an open-cut tunnel crossing an existing culvert structure.

[0005] According to an embodiment of the first aspect of the present invention, an open-cut tunnel spanning over an existing culvert structure includes:

[0006] There are existing culverts;

[0007] A tunnel structure is arranged above the existing culvert at intervals, and the tunnel structure and the existing culvert are arranged obliquely;

[0008] A plurality of pile foundations, supporting the tunnel structure, with a preset clearance between each pile foundation and the existing culvert;

[0009] The protective structure includes a slope reduction module and a support module. The slope reduction module and the support module cooperate to define the range of the tunnel structure. The slope reduction modules are respectively arranged at the two intersections of the tunnel structure and the existing culvert, and the support modules are adjacent to the remaining positions within the range of each slope reduction module.

[0010] According to the first aspect of the present invention, the open-cut tunnel crosses the existing culvert structure, which has at least the following beneficial effects: by partially adopting the slope module and cooperating with the support module to form a foundation pit type, the normal function of the existing culvert can be guaranteed during construction, and the modification of the existing culvert is avoided. The depth of the foundation pit is reduced, the scale of the foundation pit is reduced, the excavation range is small, and it has a good ability to control surface deformation, which reduces the impact on surrounding sensitive buildings, roads, pipelines, etc., and ensures the safety of the surrounding environment during construction; by adopting the pile foundation to form an "underground bridge" to cross the existing culvert, the pile foundation bears the vertical load of the tunnel structure, so that the existing culvert and the new tunnel are each independent force systems, avoiding the mutual influence between the two, and ensuring the safety of the existing culvert and the new tunnel during the long-term use period after completion.

[0011] According to the embodiment of the first aspect of the present invention, the open-cut tunnel crosses the existing culvert structure, and the support module includes a water-stop curtain, support piles and crown beams arranged in sequence. Some of the support modules are arranged to form an opening protruding outward, and at least part of the slope module is arranged at the opening.

[0012] According to the embodiment of the first aspect of the present invention, the open-cut tunnel crosses the existing culvert structure, and the support module further includes at least two opposite supports arranged obliquely to the existing culvert and at least two diagonal supports arranged parallel to the existing culvert. The opposite supports are connected to the support modules on both sides of the same slope reduction module, and the diagonal supports are connected to the support modules on the same side of the two slope reduction modules, so that each opposite support and each diagonal support form a closed planar structure.

[0013] According to a second embodiment of the present invention, a construction method for an open-cut tunnel over an existing culvert structure comprises the following steps:

[0014] S1: According to the position of the existing culvert, determine the relative positional relationship between the tunnel structure and the existing culvert, and perform pile foundation construction of the tunnel structure, with a preset clearance between the pile foundation and the existing culvert;

[0015] S2: Carry out water-stop curtain construction of foundation pit;

[0016] S3: constructing support piles for the foundation pit, wherein local excavation and sloping are performed in the longitudinal overlapping range of the tunnel structure and the existing culvert. Support piles are installed outside the overlapping range of the tunnel structure and the existing culvert according to the location of the sloping. The construction range of the tunnel structure is defined by the location of the sloping and the support piles.

[0017] S4: Carry out the construction of the crown beam and internal support of the foundation pit;

[0018] S5: Carry out foundation pit excavation;

[0019] S6: Carry out construction and backfilling of the tunnel structure.

[0020] The construction method of an open-cut tunnel crossing an existing culvert structure according to the second embodiment of the present invention has at least the following beneficial effects: by locally adopting slope construction and setting support piles and internal supports according to the slope position, the three cooperate to form a foundation pit, which can ensure the normal function of the existing culvert during construction, avoid the modification of the existing culvert, reduce the depth of the foundation pit, reduce the scale of the foundation pit, and have a small excavation range. It has good surface deformation control ability, reduces the impact on surrounding sensitive buildings, roads, pipelines, etc., and ensures the safety of the surrounding environment during construction; by adopting pile foundations to form an "underground bridge" to cross the existing culvert, the pile foundation bears the vertical load of the tunnel structure, so that the existing culvert and the newly built tunnel are each independent force systems, avoiding the mutual influence between the two, and ensuring the safety of the existing culvert and the newly built tunnel during the long-term use period after completion.

[0021] According to the construction method of an open-cut tunnel over an existing culvert structure described in an embodiment of the second aspect of the present invention, in S1, the pile foundations are cast-in-place piles, and at least part of the pile foundations are assisted by steel casings.

[0022] According to the construction method of an open-cut tunnel over an existing culvert structure described in an embodiment of the second aspect of the present invention, in S2, the water-stop curtain uses densely packed cement mixing piles, and the water-stop curtain passes through the permeable layer and enters a preset depth below the bottom of the foundation pit.

[0023] According to the construction method of an open-cut tunnel crossing an existing culvert structure described in an embodiment of the second aspect of the present invention, in S3, water-stop curtains and support piles are respectively provided on both sides of the slope reduction position, and the water-stop curtains and support piles provided outside the overlapping position range of the tunnel structure and the existing culvert are respectively connected to form a whole.

[0024] According to the construction method of an open-cut tunnel crossing an existing culvert structure described in an embodiment of the second aspect of the present invention, in S4, steel bars anchored in the crown beam are reserved on the top of the support piles, and the internal support includes a brace perpendicular to the existing culvert and a diagonal brace parallel to the existing culvert, and the diagonal brace and the brace respectively connect parts of the crown beam.

[0025] According to the construction method of an open-cut tunnel crossing an existing culvert structure described in an embodiment of the second aspect of the present invention, in S5, the foundation pit is constructed using the retreat excavation method and is excavated symmetrically layer by layer. After excavation reaches the bottom of the foundation pit, a closed cushion layer is laid, and mesh spraying is used for protection between the support piles on both sides of the slope position.

[0026] According to the construction method of an open-cut tunnel crossing an existing culvert structure described in an embodiment of the second aspect of the present invention, in S6, the bottom plate waterproofing, bottom plate structure, backfilling of plain concrete on both sides of the bottom plate, side wall structure, and side wall waterproofing of the tunnel structure are sequentially performed. After the structure reaches the designed strength, stone chips are backfilled on both sides of the side wall. A preset length of steel bar is reserved on the top of the pile foundation for anchoring into the bottom plate of the tunnel structure.

[0027] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The present invention will be further described below with reference to the accompanying drawings and embodiments;

[0029] Figure 1 A plan view of an embodiment of the present invention;

[0030] Figure 2 It is a cross-sectional view of an embodiment of the present invention. DETAILED DESCRIPTION

[0031] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0032] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0033] In the description of the present invention, "several" means one or more, "many" means at least two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0034] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0035] Reference Figures 1 and 2 The open-cut tunnel of the first embodiment of the present invention crosses the existing culvert structure, including the existing culvert 2, the tunnel structure 9, a plurality of pile foundations 1 and a protective structure.

[0036] In some specific construction embodiments, the existing culvert 2 is a flood discharge culvert with an arch culvert structure. The geological conditions are mainly fill, wherein the top plate and bottom plate are prefabricated reinforced concrete structures, and the side walls are stone masonry structures.

[0037] The tunnel structure 9 is arranged above the existing culvert 2 at intervals, and the tunnel structure 9 is arranged obliquely to the existing culvert 2; in some specific construction embodiments, the tunnel structure 9 is a U-shaped trough structure, the structural net distance between the top plate of the existing culvert 2 and the bottom plate structure 8 of the tunnel structure 9 is about 1.5m, and the centerline angle between the existing culvert 2 and the tunnel structure 9 is about 75°.

[0038] Each pile foundation 1 is used to support the tunnel structure 9, forming an "underground bridge" type across the existing culvert 2, and there is a preset clearance between each pile foundation 1 and the existing culvert 2 to ensure that the two are independent of each other and are not affected; in some specific construction embodiments, the clearance between the pile foundation 1 and the existing culvert 2 is ≥1m.

[0039] The protective structure includes a slope reduction module 11 and a support module. The slope reduction module 11 and the support module cooperate to define the scope of the tunnel structure 9. The slope reduction modules 11 are respectively arranged at the two intersections of the tunnel structure 9 and the existing culvert 2, and the support modules are adjacent to the slope reduction modules 11 at the remaining locations within the scope. It can be understood that the protective structure is used to withstand the main horizontal earth pressure or landslide thrust, but the top of the existing culvert 2 cannot be used as a support pile 5. Therefore, a local slope reduction arrangement is adopted at the two intersections of the tunnel structure 9 and the existing culvert 2, that is, the top of the existing culvert. The support piles 5 are used to withstand the lateral thrust in the remaining areas, ensuring the normal construction of the tunnel structure 9 without affecting the existing culvert 2.

[0040] By locally adopting the slope reduction module 11 and cooperating with the support module to form a foundation pit type, the normal function of the existing culvert 2 can be guaranteed during the construction period, and the modification of the existing culvert 2 is avoided. The foundation pit depth is reduced, the foundation pit scale is reduced, the excavation range is small, and the ability to control surface deformation is good, which reduces the impact on surrounding sensitive buildings, roads, pipelines, etc., and ensures the safety of the surrounding environment during construction; by adopting the pile foundation 1 to form an "underground bridge" type to cross the existing culvert 2, the pile foundation 1 bears the vertical load of the tunnel structure 9, so that the existing culvert 2 and the newly built tunnel are each independent force systems, avoiding the mutual influence between the two, and ensuring the safety of the existing culvert 2 and the newly built tunnel during the long-term use period after completion.

[0041] In some embodiments of the present invention, the support modules include a water-stop curtain 4, support piles 5, and a crown beam 7, which are arranged in sequence. Some of the support modules are arranged to form an outwardly protruding opening, with at least a portion of the grading module 11 positioned within the opening. It is understood that the water-stop curtain 4 and support piles 5 are arranged sequentially from the outside inward, with the crown beam 7 supporting, distributing, and transferring loads, connecting all the support piles 5 to prevent collapse at the top edge of the foundation pit. It is understood that cast-in-place support piles are more effective.

[0042] In some embodiments of the present invention, the support module further includes at least two cross braces arranged obliquely across the existing culvert 2 and at least two diagonal braces arranged parallel to the existing culvert 2. The cross braces are connected to the support modules on both sides of the same slope-reducing module 11, and the diagonal braces are connected to the support modules on the same side of two slope-reducing modules 11, so that each cross brace and each diagonal brace form a closed planar structure. In combination with the special-shaped protective structure, internal braces 6 are provided to ensure construction safety. After the entire structure is assembled, they are welded to the embedded parts in the crown beam 7.

[0043] In some embodiments of the present invention, a concrete protective structure is provided between the slope reduction module 11 and the support module to protect the slope from weathering and rainfall erosion from the outside to the inside. A steel mesh or hanging mesh is provided within the concrete protective structure, and the slope hanging mesh spraying method achieves better results.

[0044] Reference Figures 1 and 2 The construction method of an open-cut tunnel over an existing culvert structure according to the second embodiment of the present invention comprises the following steps:

[0045] S1: Based on the position of the existing culvert 2, the relative position relationship between the tunnel structure 9 and the existing culvert 2 is confirmed. The site is leveled and the pile foundation 1 of the tunnel structure 9 is constructed. Reliable measures are taken during the construction process to ensure the safety of the existing culvert 2. A preset clearance is maintained between the pile foundation 1 and the existing culvert 2.

[0046] S2: Construction of water-stop curtain 4 of foundation pit;

[0047] S3: Construction of support piles 5 of the foundation pit is carried out, wherein local excavation and sloping are carried out in the longitudinal overlapping position range of the tunnel structure 9 and the existing culvert 2. In accordance with the position of the sloping, support piles 5 are set outside the overlapping position range of the tunnel structure 9 and the existing culvert 2. The construction range of the tunnel structure 9 is defined by the position of the sloping and the support piles 5. The center distance between adjacent support piles 5 should be less than 2D and the net distance between support piles 5 should not be greater than 1.0m.

[0048] S4: Based on the irregular distribution of the support piles 5 on the plane, the crown beam 7 and the inner support 6 of the foundation pit are constructed;

[0049] S5: Carry out foundation pit excavation construction. Excavation should start after the foundation pit protection structure reaches the design strength;

[0050] S6: Construction and backfilling of the tunnel structure 9 are carried out.

[0051] Furthermore, the mutual influence between the tunnel structure 9 and the existing culvert 2 can be analyzed before S1. Based on the spatial relationship between the open-cut tunnel structure 9 and the existing culvert 2 and the structural type of the existing culvert 2, the mutual influence during the construction period and the post-completion service period can be evaluated, and a feasible construction method can be proposed.

[0052] By locally adopting the construction of slope reduction and setting the support piles 5 and the internal supports 6 according to the slope reduction position, the three cooperate to form a foundation pit, which can ensure the normal function of the existing culvert 2 during construction, avoid the modification of the existing culvert 2, reduce the depth of the foundation pit, reduce the scale of the foundation pit, and have a small excavation range. It has a good ability to control surface deformation, reduces the impact on surrounding sensitive buildings, roads, pipelines, etc., and ensures the safety of the surrounding environment during construction; by adopting the pile foundation 1 to form an "underground bridge" type to cross the existing culvert 2, the pile foundation 1 bears the vertical load of the tunnel structure 9, so that the existing culvert 2 and the newly built tunnel are each independent force systems, avoiding the mutual influence between the two, and ensuring the safety of the existing culvert 2 and the newly built tunnel during the long-term use period after completion.

[0053] In some embodiments of the present invention, in S1, the pile foundation 1 is a cast-in-place pile, and at least part of the pile foundation 1 is provided with a steel casing 3, and at least part of the pile foundation 1 uses the steel casing 3 to assist in drilling to protect the existing culvert 2.

[0054] In some embodiments of the present invention, in S2, the water-stop curtain 4 uses densely packed cement mixing piles. The water-stop curtain 4 passes through the permeable layer and enters a preset depth below the bottom of the foundation pit, ensuring that groundwater from the side walls and bottom of the foundation pit is prevented or reduced from flowing into the foundation pit.

[0055] In some embodiments of the present invention, in S3, water-stop curtains 4 and support piles 5 are also installed on both sides of the slope-reduction position. These curtains 4 and support piles 5 are connected to the areas outside the overlap between the tunnel structure 9 and the existing culvert 2 to form a single structure. It is understood that the slope-reduction position can be connected to the support piles 5 to form a continuous support structure capable of withstanding lateral thrust. To ensure that both sides of the slope-reduction position also have a certain degree of protection, additional water-stop curtains 4 and support piles 5 are installed on both sides of the slope-reduction position to ensure comprehensive protection.

[0056] In some embodiments of the present invention, in S4, steel bars anchored in the crown beam 7 are reserved at the top of the supporting pile 5, and the internal support 6 includes a cross-bracing perpendicular to the existing culvert 2 and a diagonal bracing parallel to the existing culvert 2. The diagonal bracing and the cross-bracing respectively connect part of the crown beam 7 to ensure the quality of the foundation pit.

[0057] In some embodiments of the present invention, in S5, the ground around the foundation pit boundary is hardened and drainage ditches are installed before excavation. The foundation pit is constructed using the retreat method, with symmetrical excavation layer by layer. When the foundation pit is excavated to 300 mm from the pit bottom, manual excavation is required to prevent over-excavation. After excavation reaches the bottom of the foundation pit, a closed cushion layer 10 is laid, that is, a cushion layer 10 is provided between the pile foundation 1 and the tunnel structure 9. Netting and spraying concrete are used for protection on both sides of the slope and between the support piles 5. Timely implementation of slope and inter-pile protection ensures construction safety.

[0058] In some embodiments of the present invention, in S6, the bottom plate waterproofing of the tunnel structure 9, the bottom plate structure 8, the backfilling of plain concrete on both sides of the bottom plate, the side wall structure, and the side wall waterproofing are sequentially performed. After the structure reaches the design strength, the stone chips are backfilled on both sides of the side wall. A preset length of steel bars is reserved on the top of the pile foundation 1 for anchoring into the bottom plate structure 8 of the tunnel structure 9. Preferably, a reserved length of steel bars ≥30d is anchored into the bottom plate structure 8 of the tunnel structure 9 to ensure a reliable connection between the two.

[0059] The technical features of the above-mentioned embodiments can be combined arbitrarily. In order to make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0060] The embodiments of the present invention are described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various changes can be made within the scope of knowledge possessed by ordinary technicians in the technical field without departing from the scope of the present invention.

Claims

1. An open-cut tunnel spanning an existing culvert structure, characterized in that: include: There are existing culverts; A tunnel structure is arranged above the existing culvert at intervals, and the tunnel structure and the existing culvert are arranged obliquely; A plurality of pile foundations, supporting the tunnel structure, with a preset clearance between each pile foundation and the existing culvert; The protective structure includes a slope reduction module and a support module. The slope reduction module and the support module cooperate to define the range of the tunnel structure. The slope reduction modules are respectively arranged at two intersections of the tunnel structure and the existing culvert. The support modules are adjacent to the remaining positions within the range of each slope reduction module. The support module includes a water-stop curtain, support piles and a crown beam arranged in sequence, and some of the support modules are arranged to form an opening protruding outward, and at least part of the sloping module is arranged at the opening; The support module also includes at least two opposite supports arranged obliquely to the existing culvert and at least two diagonal supports arranged parallel to the existing culvert. The opposite supports are connected to the support modules on both sides of the same slope reduction module, and the diagonal supports are connected to the support modules on the same side of the two slope reduction modules, so that each opposite support and each diagonal support form a closed planar structure.

2. A construction method for an open-cut tunnel over an existing culvert structure, characterized in that: The method for forming an open-cut tunnel over an existing culvert structure as claimed in claim 1 comprises the following steps: S1: According to the position of the existing culvert, determine the relative positional relationship between the tunnel structure and the existing culvert, and perform pile foundation construction of the tunnel structure, with a preset clearance between the pile foundation and the existing culvert; S2: Carry out water-stop curtain construction of foundation pit; S3: constructing support piles for the foundation pit, wherein local excavation and sloping are performed in the longitudinal overlapping range of the tunnel structure and the existing culvert. Support piles are installed outside the overlapping range of the tunnel structure and the existing culvert according to the location of the sloping. The construction range of the tunnel structure is defined by the location of the sloping and the support piles. S4: Carry out the construction of the crown beam and internal support of the foundation pit; S5: Carry out foundation pit excavation; S6: Carry out construction and backfilling of the tunnel structure; In S3, water-stop curtains and support piles are also provided on both sides of the slope reduction position, and the water-stop curtains and support piles provided outside the overlapping position of the tunnel structure and the existing culvert are respectively connected to form a whole; In S4, a steel bar anchored in the crown beam is reserved on the top of the support pile, and the internal support includes a brace obliquely intersecting the existing culvert and a diagonal brace parallel to the existing culvert, and the diagonal brace and the brace respectively connect parts of the crown beam.

3. The construction method of an open-cut tunnel over an existing culvert structure according to claim 2 is characterized in that: In S1, the pile foundation is a cast-in-place pile, and at least part of the pile foundation is assisted by a steel casing.

4. The construction method of an open-cut tunnel over an existing culvert structure according to claim 2, characterized in that: In S2, the water-stop curtain is formed by densely packed cement mixing piles, and the water-stop curtain passes through the permeable layer and enters a preset depth below the bottom of the foundation pit.

5. The construction method of an open-cut tunnel over an existing culvert structure according to claim 2 is characterized in that: In S5, the foundation pit is constructed by retreat excavation method and is excavated symmetrically layer by layer. After excavation to the bottom of the foundation pit, a closed cushion layer is laid, and mesh spraying is used for protection between the supporting piles on both sides of the slope position.

6. The construction method of an open-cut tunnel over an existing culvert structure according to claim 2, characterized in that: In S6, the bottom plate waterproofing, bottom plate structure, backfilling of plain concrete on both sides of the bottom plate, side wall structure, and side wall waterproofing of the tunnel structure are sequentially performed. After the structure reaches the designed strength, stone chips are backfilled on both sides of the side wall. A preset length of steel bar is reserved on the top of the pile foundation for anchoring into the bottom plate of the tunnel structure.

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