Supporting structure and box culvert integrated construction method for underneath passing existing bridge in limited space

Abstract

The invention provides a supporting structure and box culvert integrated construction method for underneath passing of an existing bridge in a limited space. The method comprises the following steps that S1, construction preparation is conducted; s2, construction of cast-in-place piles; s3, high-pressure jet grouting pile construction; s4, breaking the pile head; s5, supporting structure construction; s6, earth excavation is conducted; s7, planting steel bars; the pile head of the third cast-in-place pile 7 is broken, and chiseling and bar planting treatment is conducted on the second cast-in-place pile 5; s8, box culvert formwork erecting pouring construction is completed; and S9, earthwork layered filling and rolling construction are conducted. On the premise that traffic operation safety of the existing road is guaranteed, the use requirement of a new project is met, meanwhile, the excavation earth volume of the foundation pit and the formwork project amount are reduced, the problems are solved, and the method has the advantages of being high in operability, reliability and safety.

Description

Technical Field

[0001] The invention belongs to the field of water conservancy projects, and in particular relates to an integrated construction method of a support structure and a box culvert that passes under an existing bridge in a limited space. Background Art

[0002] New flood control facilities need to pass under existing bridges. Since they are too close to the bridge piers on both sides, the deformation of the bridge facilities is strictly controlled. How to ensure that the underpass construction is successfully completed without affecting the long-term operational safety of the existing bridge is a key issue in related projects.

[0003] The following are the main problems in the construction of box culverts under existing bridges in limited spaces: 1. The clear height between the original landform and the bridge beams and slabs is small, and conventional mechanical equipment cannot meet the construction requirements; 2. The bridge piers on both sides are closer to the box culvert, and disturbances during construction are likely to cause deformation; 3. Due to the replenishment of river water levels, the impact of water level changes on construction safety cannot be ignored; 4. The foundation pit is deep, and excavation is prone to settlement; 5. Bridge traffic operation cannot be interrupted during construction; 6. The excavation process causes a large vertical displacement of the bridge structure. Summary of the invention

[0004] In view of this, the present invention aims to propose an integrated construction method of a support structure and a box culvert that passes under an existing bridge in a limited space, which adopts a comprehensive construction process technology combining "slope + supporting cast-in-place piles + interlocking high-pressure rotary jet piles + internal support beam type". While ensuring the safety of existing highway traffic operations and meeting the needs of new construction projects, the amount of earth excavation and formwork engineering is reduced, the above-mentioned problems are solved, and the method has the advantages of strong operability, high reliability and high safety.

[0005] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0006] A method for integrated construction of a support structure and a box culvert under an existing bridge in a limited space, further comprising the following steps:

[0007] S1. Construction preparation: site leveling and surveying, and local excavation into a slope form;

[0008] S2, cast-in-place pile construction: carry out the construction of the first cast-in-place pile, the second cast-in-place pile and the third cast-in-place pile;

[0009] S3, high-pressure rotary jet grouting pile construction: after the strength of the first cast-in-place piles on both sides reaches 80%, the high-pressure rotary jet grouting piles on both sides are constructed;

[0010] S4, breaking the pile heads; after the strength of the cast-in-place piles and high-pressure rotary jet piles reaches 100%, carry out layered excavation of earthwork to support the top support construction elevation of the cast-in-place piles, and break the pile heads of the first cast-in-place pile, the second cast-in-place pile and the high-pressure rotary jet pile;

[0011] S5. Support structure construction: Concrete crown beams, connecting beams and inner support beams are constructed to form a circle of support structure;

[0012] S6. Earthwork excavation: excavate the earthwork in layers to the bottom of the foundation pit, hang steel mesh and spray fine stone concrete while excavating;

[0013] S7, rebar planting; breaking the third cast-in-place pile 7, and roughening and rebar planting the second cast-in-place pile 5;

[0014] S8. Complete the box culvert formwork pouring construction;

[0015] S9. Earthwork is filled and compacted in layers.

[0016] Furthermore, in step S1, slope excavation is performed from the edge line, and the soil within the slope foot range is excavated to increase the construction space under the existing bridge.

[0017] Further, in step S2, firstly, the first cast-in-place pile is constructed, and the construction sequence is skipped by skipping two piles at a time, and then the second cast-in-place pile and the third cast-in-place pile are constructed;

[0018] During the construction of the first, second and third cast-in-place piles, the pile positions must be accurately laid out and the verticality of the pile positions must be maintained during the drilling process.

[0019] Furthermore, the cast-in-place pile reinforcement cage is made in sections, with each section being 4m long. After the drilling inspection and acceptance is qualified, the reinforcement cage is placed;

[0020] When lowering the steel cage, lower it slowly and adjust the verticality of the steel cage into the hole at any time according to the depth of the cage to avoid tilting and swinging; the main reinforcement joints are welded joints;

[0021] The hole cleaning is carried out in two times. The first hole cleaning is carried out immediately after the hole is drilled, and the second time is carried out after the steel cage is lowered and the concrete conduit is installed. After the second hole cleaning is accepted, the bored pile concrete is poured.

[0022] Furthermore, in step S3; after the strength of the first bored pile reaches 80%, the double-tube method is used to construct the high-pressure rotary jet pile 6, the cement content is 20%, the pressure of the high-pressure cement slurry is not less than 25MPa, the flow rate is not less than 70L / min, the air flow pressure is not less than 0.6MPa, and the lifting speed is 0.1m / min~0.2m / min.

[0023] Furthermore, in step S4, after the strength of the first cast-in-place pile, the second cast-in-place pile, the third cast-in-place pile and the high-pressure rotary jet pile reaches 100%, the earthwork is excavated in layers by means of manual and mechanical operations in coordination with each other, and the excavation is carried out to the top support elevation of the first cast-in-place pile and the second cast-in-place pile; the pile heads of the first cast-in-place pile, the second cast-in-place pile and the high-pressure rotary jet pile are broken by manual hand-held wind.

[0024] Furthermore, in step S5, the concrete crown beam, connecting beam and supporting beam are constructed, and the ends of both sides of the supporting beam are connected to the crown beam and connecting beam by horizontal abutments to increase the strength and overall stability of the supporting structure; finally, the crown beam, connecting beam and supporting beam are poured with concrete.

[0025] Furthermore, in step S6, mechanical operation is used to excavate the earthwork in layers, evenly and symmetrically, and the thickness of each layer of earthwork excavation does not exceed 2m. After the excavation is completed, a steel mesh is immediately hung on the inner side of the first cast-in-place piles on both sides and fine stone concrete is sprayed;

[0026] After the upper construction work is completed, the next layer of earth excavation will be carried out until the excavation reaches the top of the third cast-in-place pile.

[0027] Furthermore, in step S7, when the excavation reaches a position of 30 cm from the bottom of the foundation pit, the bottom of the foundation pit is manually excavated to expose all the third cast-in-place pile heads; the pile heads of the third cast-in-place piles are broken by manual and mechanical methods, and the second cast-in-place piles are roughened and rebar-planted.

[0028] Further, in step S8, the construction process of the box culvert formwork casting is as follows: foundation cushion concrete casting; bottom plate steel bar binding and formwork installation; bottom plate concrete casting; side wall steel bar binding and formwork installation; side wall concrete casting; top plate steel bar binding and formwork installation; box culvert top plate concrete casting; during the box culvert construction, the second cast-in-place pile and the box culvert middle pier need to be cast as a whole; the walls on both sides of the box culvert are close to the first cast-in-place pile, and no formwork is required;

[0029] In step S9, after the top slab of the box culvert is poured and its strength is stabilized, manual soil spreading and small-scale rammers are used to carry out layered filling and compaction to restore the original landform.

[0030] Compared with the prior art, the integrated construction method of the support structure and box culvert for passing under an existing bridge in a limited space described in the present invention has the following advantages:

[0031] (1) The present invention provides an integrated construction method for a support structure and a box culvert that passes under an existing bridge in a limited space. The construction process adopts a slope type + supporting cast-in-place piles + support beams. The cast-in-place piles are used as the middle piers of the box culvert and also as the supporting structure of the foundation pit. There is no need to slope the foundation pit, which reduces the amount of earth excavation in the foundation pit. The cast-in-place piles and the high-pressure rotary jet piles are engaged with each other to form a water-stop curtain, which has good support and water-stopping effects. The cast-in-place piles on both sides are close to the outer wall of the box culvert, and no cast-in-place formwork is required, which makes construction convenient.

[0032] (2) The present invention provides an integrated construction method for a support structure and a box culvert that passes under an existing bridge in a limited space, which solves the technical problems of tight structural space, high requirements for settlement and deformation control, and traffic operation when the space for the water inlet box culvert under the bridge is limited in a newly built water conservancy project. It meets the needs of new construction projects while ensuring the safety of existing highway traffic operations, and has strong operability, high reliability, and high safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] The accompanying drawings constituting a part of the present invention are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the accompanying drawings:

[0034] Figure 1 A schematic diagram of a support structure for passing under an existing bridge in a limited space according to an embodiment of the present invention;

[0035] Figure 2 A top view of a supporting structure for passing under an existing bridge in a limited space according to an embodiment of the present invention;

[0036] Figure 3 It is a front view of a supporting structure for passing under an existing bridge in a limited space according to an embodiment of the present invention.

[0037] Description of reference numerals:

[0038] 1. Bridge pier; 2. Slope; 3. Erected bridge; 4. First cast-in-place pile; 5. Second cast-in-place pile; 6. High-pressure jet jet pile; 7. Third cast-in-place pile; 8. Concrete cap beam; 9. Concrete connecting beam; 10. Concrete inner support beam; 11. Steel mesh; 12. Box culvert; 13. Box culvert middle pier; 14. Box culvert top plate. DETAILED DESCRIPTION

[0039] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0040] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and the like are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", and the like may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood by specific circumstances.

[0042] The present invention will be described in detail below with reference to the accompanying drawings and in conjunction with embodiments.

[0043] A method for integrating a support structure and a box culvert 12 for passing under an existing bridge in a limited space comprises the following steps:

[0044] S1. Construction preparation: level the site, measure and lay out the lines, and excavate the site into a slope 2; preferably, excavate the slope from the sideline, remove the soil within the slope foot range, and increase the construction space under the existing bridge.

[0045] S2, cast-in-place pile construction; the first cast-in-place pile 4, the second cast-in-place pile 5 and the third cast-in-place pile 7 are constructed; preferably, the first cast-in-place pile 4 is constructed first, and the sequence construction is performed by skipping two piles each time, and then the second cast-in-place pile 5 and the third cast-in-place pile 7 are constructed;

[0046] During the construction of the first cast-in-place pile 4 , the second cast-in-place pile 5 and the third cast-in-place pile 7 , the pile positions must be accurately laid out and the verticality of the pile positions must be maintained during the drilling process.

[0047] Preferably, the cast-in-place pile reinforcement cage is made in sections, each section is 4m, and the reinforcement cage is placed after the drilling inspection and acceptance is qualified;

[0048] When lowering the steel cage, lower it slowly and adjust the verticality of the steel cage into the hole at any time according to the depth of the cage to avoid tilting and swinging; the main reinforcement joints are welded joints;

[0049] The hole cleaning is carried out in two times. The first hole cleaning is carried out immediately after the hole is drilled, and the second time is carried out after the steel cage is lowered and the concrete conduit is installed. After the second hole cleaning is accepted, the bored pile concrete is poured.

[0050] S3, construction of high-pressure rotary jet piles 6; after the strength of the first cast-in-place piles 4 on both sides reaches 80%, the construction of high-pressure rotary jet piles 6 on both sides is carried out; preferably, after the strength of the first cast-in-place piles 4 reaches 80%, the double-tube method is used to construct the high-pressure rotary jet piles 66, the cement content is 20%, the pressure of the high-pressure cement slurry is not less than 25MPa, the flow rate is not less than 70L / min, the air flow pressure is not less than 0.6MPa, and the lifting speed is 0.1m / min~0.2m / min.

[0051] S4, breaking the pile head; after the strength of the bored pile and the high-pressure rotary jet pile 6 reaches 100%, the earthwork is excavated in layers to support the construction elevation of the top support of the bored pile, and the pile heads of the first bored pile 4, the second bored pile 5 and the high-pressure rotary jet pile 6 are broken; preferably, after the strength of the first bored pile 4, the second bored pile 5, the third bored pile 7 and the high-pressure rotary jet pile 6 reaches 100%, the earthwork is excavated in layers by means of manual and mechanical operations in coordination, and the excavation is carried out to the top support elevation of the first bored pile 4 and the second bored pile 5; the pile heads of the first bored pile 4, the second bored pile 5 and the high-pressure rotary jet pile 6 are broken by manual handheld wind.

[0052] S5, support structure construction; construct concrete crown beam 8, connecting beam and inner support beam to form a circle of support structure; preferably, construct concrete crown beam 8, connecting beam and support beam, and both side ends of the support beam are connected to the crown beam and connecting beam by horizontal axils to increase the strength and overall stability of the support structure; finally, pour concrete for the crown beam, connecting beam and support beam.

[0053] S6, earthwork excavation; excavate the earthwork in layers to the bottom of the foundation pit, hang the steel mesh 11 and spray fine stone concrete while excavating; preferably, mechanical operation is used to excavate the earthwork in layers, evenly and symmetrically, and the thickness of each layer of earthwork excavation does not exceed 2m. After the excavation is completed, the steel mesh 11 is immediately hung on the inner side of the first cast-in-place piles 4 on both sides and fine stone concrete is sprayed;

[0054] After the upper layer construction work is completed, the next layer of earthwork excavation construction is carried out until the excavation reaches the top of the third cast-in-place pile 7.

[0055] S7, rebar planting; break the third cast-in-place pile 77, and roughen and rebar the second cast-in-place pile 55; preferably, when excavating to a position 30 cm from the bottom of the foundation pit, manually excavate to the bottom of the foundation pit to expose all the third cast-in-place pile 7 heads; use manual and mechanical methods to break the pile head of the third cast-in-place pile 7, and roughen and rebar the second cast-in-place pile 5.

[0056] S8, complete the box culvert 12 formwork pouring construction; preferably, the box culvert 12 formwork pouring construction process is: foundation cushion concrete pouring; bottom plate steel bar binding, formwork installation; bottom plate concrete pouring; side wall steel bar binding, formwork installation; side wall concrete pouring; top plate steel bar binding, formwork installation; box culvert top plate 14 concrete pouring; during the construction of the box culvert 12, it is necessary to cast the second cast-in-place pile 5 and the box culvert middle pier 13 into a whole; the walls on both sides of the box culvert 12 are close to the first cast-in-place pile 4, and no formwork is required;

[0057] S9, earthwork layered filling and rolling construction; after the box culvert top plate 14 is poured and its strength is stabilized, manual soil spreading combined with small-scale rammers are used to carry out layered filling and compaction to restore the original landform.

[0058] This construction method adopts a comprehensive construction technology that combines "slope 2 + supporting cast-in-place piles + interlocking high-pressure rotary jet piles 6 + internal support beam type". While meeting the needs of new construction projects under the premise of ensuring the safety of existing highway traffic operations, it reduces the amount of foundation pit excavation and formwork engineering. It has the advantages of strong operability, high reliability and high safety.

[0059] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for integrated construction of a support structure and a box culvert under an existing bridge in a limited space, characterized in that: The following steps are involved: S1. Construction preparation: site leveling and surveying, and local excavation into a slope form; S2, cast-in-place pile construction: carry out the construction of the first cast-in-place pile, the second cast-in-place pile and the third cast-in-place pile; S3, high-pressure rotary jet grouting pile construction: after the strength of the first cast-in-place piles on both sides reaches 80%, the high-pressure rotary jet grouting piles on both sides are constructed; S4, breaking the pile heads; after the strength of the cast-in-place piles and high-pressure rotary jet piles reaches 100%, carry out layered excavation of earthwork to support the top support construction elevation of the cast-in-place piles, and break the pile heads of the first cast-in-place pile, the second cast-in-place pile and the high-pressure rotary jet pile; S5. Construction of supporting structure: Construction of concrete crown beams, connecting beams and inner support beams to form a circle of supporting structure; S6. Earthwork excavation: excavate the earthwork in layers to the bottom of the foundation pit, hang steel mesh and spray fine stone concrete while excavating; S7, rebar planting; breaking the third cast-in-place pile 7 pile head, and roughening and rebar planting the second cast-in-place pile 5 pile; S8. Complete the box culvert formwork pouring construction; S9. Earthwork is filled and compacted in layers.

2. The method for integrated construction of a support structure and a box culvert for passing under an existing bridge in a limited space according to claim 1, characterized in that: In step S1, slope excavation is performed from the edge line, and the soil within the slope foot range is excavated to increase the construction space under the existing bridge.

3. The method for integrated construction of a supporting structure and a box culvert for passing under an existing bridge in a limited space according to claim 2, characterized in that: In step S2, firstly, the first cast-in-place pile is constructed, and the construction sequence is skipped by skipping two piles at a time, and then the second cast-in-place pile and the third cast-in-place pile are constructed; During the construction of the first, second and third cast-in-place piles, the pile positions must be accurately laid out and the verticality of the pile positions must be maintained during the drilling process.

4. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 3, characterized in that: The reinforced cage of the cast-in-place pile is made in sections, each section is 4m long. After the drilling inspection is passed, the reinforced cage is placed; When lowering the steel cage, lower it slowly and adjust the verticality of the steel cage into the hole at any time according to the depth of the cage to avoid tilting and swinging; the main reinforcement joints are welded joints; The hole cleaning is carried out in two times. The first hole cleaning is carried out immediately after the hole is drilled, and the second time is carried out after the steel cage is lowered and the concrete conduit is installed. After the second hole cleaning is accepted, the bored pile concrete is poured.

5. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 1, characterized in that: In the step S3; after the strength of the first bored pile reaches 80%, the double-tube method is used for high-pressure jet grouting pile 6 construction, the cement content is 20%, the pressure of the high-pressure cement slurry is not less than 25MPa, the flow rate is not less than 70L / min, the air flow pressure is not less than 0.6MPa, and the lifting speed is 0.1m / min~0.2m / min.

6. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 1, characterized in that: In step S4, after the strength of the first cast-in-place pile, the second cast-in-place pile, the third cast-in-place pile and the high-pressure rotary jet pile reaches 100%, the earthwork is excavated in layers by means of manual and mechanical operations in coordination, and the excavation is carried out to the top support elevation of the first cast-in-place pile and the second cast-in-place pile; the pile heads of the first cast-in-place pile, the second cast-in-place pile and the high-pressure rotary jet pile are broken by manual hand-held wind.

7. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 1, characterized in that: In step S5, the concrete crown beam, connecting beam and supporting beam are constructed, and the ends of the supporting beams are connected to the crown beam and connecting beam by horizontal axils to increase the strength and overall stability of the supporting structure; finally, the crown beam, connecting beam and supporting beam are poured with concrete.

8. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 1, characterized in that: In step S6, mechanical operation is used to excavate the earth in layers, evenly and symmetrically, and the thickness of each layer of earth excavation does not exceed 2m. After the excavation is completed, a steel mesh is immediately hung on the inner side of the first cast-in-place piles on both sides and fine stone concrete is sprayed; After the upper construction work is completed, the next layer of earth excavation will be carried out until the excavation reaches the top of the third cast-in-place pile.

9. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 1, characterized in that: In step S7, when the excavation reaches a position of 30 cm from the bottom of the foundation pit, the third cast-in-place pile heads are exposed by manual excavation to the bottom of the foundation pit; the third cast-in-place pile heads are broken by manual and mechanical methods, and the second cast-in-place piles are roughened and reinforced.

10. The method for integrated construction of a supporting structure and a box culvert under an existing bridge in a limited space according to claim 1, characterized in that: In step S8, the construction process of the box culvert formwork casting is as follows: pouring the foundation cushion concrete; tying the bottom plate steel bars and installing the formwork; pouring the bottom plate concrete; tying the side wall steel bars and installing the formwork; pouring the side wall concrete; tying the top plate steel bars and installing the formwork; pouring the top plate concrete of the box culvert; during the construction of the box culvert, it is necessary to cast the second cast-in-place pile and the middle pier of the box culvert into a complete whole; the walls on both sides of the box culvert are close to the first cast-in-place pile, and no formwork is required; In step S9, after the top slab of the box culvert is poured and its strength is stabilized, manual soil spreading and small-scale rammers are used to carry out layered filling and compaction to restore the original landform.

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