Substructure enclosure excavation construction method for existing bridge reconstruction

Abstract

The present application relates to a kind of lower structure enclosure excavation construction methods for existing bridge reconstruction, comprising: 1) using jet grouting pile as water stop curtain in the enclosure outside;2) lower structure enclosure uses caisson, according to the plane position relationship of existing bridge, install special-shaped caisson in block site, form whole;3) the deep caisson of special-shaped caisson inserts into soil body, as the construction enclosure part of pile cap;Shallow caisson is located on part of deep caisson, and is seated on pile cap, for pier column construction enclosure;4) according to the elevation position relationship of existing bridge, caisson is segmented and matched and sunk;5) in the gap of enclosure outside and water stop curtain, using jet grouting pile to locally reinforce water stop;6) the intersection of the bottom of shallow caisson blade foot and the top of pile cap is used after sand bag accumulation, pours underwater concrete;7) remove the interval break part of enclosure between deep caisson and shallow caisson.The present application is simple, safe in construction, solves the problem that construction space is insufficient and enclosure cannot be normally set when existing bridge is reconstructed.

Description

Technical Field

[0001] This invention relates to a substructure enclosure structure for the renovation of existing bridges, and more particularly to a construction method for situations where construction space is insufficient and the enclosure cannot be properly installed. Background Technology

[0002] In recent years, with the increase in road traffic and the upgrading of urban bridges, the reconstruction of existing bridges has become increasingly difficult due to the limited available construction space. When reconstructing the substructure of existing bridges, the space beneath the bridge is limited, making it difficult to directly construct the retaining structure of the abutments.

[0003] Meanwhile, with the expansion of production scale and the development of production technology, caisson construction has gradually become a form of retaining structure for various underground industrial buildings buried in soft soil layers. New developments have also been made in the application of caissons for bridge abutment foundations.

[0004] Against this backdrop, the caisson was prefabricated in sections, assembled on site, and then sunk. Rubber strips were fixed to the bottom for sealing, and concrete was poured on the inside to plug the leaks. Summary of the Invention

[0005] The purpose of this invention is to solve the problem of construction of the substructure retaining structure for the reconstruction of existing bridges, especially when there is insufficient construction space and the retaining structure cannot be set up normally. This invention provides a practical and convenient method for excavation and construction of the substructure retaining structure for the reconstruction of existing bridges.

[0006] To achieve the above objectives, the technical solution of the present invention is: a method for excavation and construction of the retaining structure of the substructure for the reconstruction of existing bridges, characterized by comprising the following steps:

[0007] 1) Jet grouting piles are used as a water-stop curtain on the outside of the enclosure;

[0008] 2) Lay out and locate the plane position of the retaining structure. Based on the excavation depth and on-site construction space, caissons are assembled on-site in sections and areas.

[0009] 3) The caisson consists of a shallow caisson for the pier section and a deep caisson for the foundation section. The deep caisson is inserted into the soil and serves as the retaining structure for the foundation construction. The shallow caisson is located on the deep caisson and sits on the foundation, serving as the retaining structure for the pier construction. The deep caisson is excavated symmetrically and sunk evenly. When it sinks to the adjacent ground elevation, the deep caisson is segmented and sunk to a matching elevation with the shallow caisson, connecting the deep caisson and the shallow caisson to form a whole. The excavation is symmetrical and the sinking is even.

[0010] 4) Based on the existing bridge elevation and position relationship, the caissons are sunk in sections and matched, and lowered to the elevation, that is, the deep caissons to the bottom elevation of the retaining wall, and the shallow caissons to the top of the pier cap. Excavation is carried out to the elevation. In order to ensure that the rubber strip at the bottom of the cutting edge of the shallow caisson is in close contact with the top surface of the pier cap for initial water stop, water guns are used to disperse the sand at the bottom of the caisson.

[0011] 5) At the gap between the outer side of the enclosure and the water-stop curtain, jet grouting piles are used for local reinforcement and water-stopping.

[0012] 6) At the junction of the bottom of the shallow caisson cutting edge and the top of the foundation, sandbags are piled up and then underwater concrete is poured to further seal the leaks and waterproof the area.

[0013] 7) Remove the retaining wall separating the deep and shallow caissons.

[0014] Furthermore, in step 2), the lower structure enclosure adopts irregular caissons. According to the existing bridge planar position relationship, the irregular caissons are installed on site in sections to form a whole.

[0015] Furthermore, both the deep and shallow caissons are divided into upper and lower sections, with the shallow caisson connecting to the deep caisson on the outer side of the foundation.

[0016] Furthermore, two layers of rubber strips, one soft and one hard, are added to the cutting edge and connected with bolts to increase the sealing of the bottom.

[0017] The beneficial effects of the present invention are: (1) the caisson can be constructed under the limited space under the existing bridge by assembling and raising; (2) the cutting edge is protected by rubber strips, which can effectively reduce the gap between the caisson and the pier and prevent water and sand leakage. Attached Figure Description

[0018] Figure 1 This is an overall elevation view of the construction process of the enclosure structure of the present invention;

[0019] Figure 2 This is a schematic diagram of the overall plan view of the construction process of the enclosure structure of the present invention;

[0020] Figure 3 This is a schematic diagram of the elevation construction of the deep well retaining structure of the present invention;

[0021] Figure 4 This is a schematic diagram of the elevation construction of the shallow caisson retaining structure of the present invention;

[0022] Figure 5 , Figure 6 This is a schematic diagram of the caisson sinking process;

[0023] Figure 7 This is a schematic diagram of the segmented structure of the caisson enclosure;

[0024] Figure 8 This is a schematic diagram of the cutting edge structure of the caisson enclosure. Detailed Implementation

[0025] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0026] like Figures 1 to 6 As shown, the specific steps of the excavation and construction method for the substructure retaining structure of the present invention for the reconstruction of existing bridges are as follows:

[0027] 1) Jet grouting piles (Ⅰ) are used as a water-stop curtain on the outside of the enclosure;

[0028] 2) Lay out and locate the plane position of the retaining structure. Based on the excavation depth and on-site construction space, caissons are assembled on-site in sections and areas.

[0029] 3) The deep caisson II is excavated symmetrically and sunk evenly. When it sinks to the nearby ground level, the upper and lower sections of the deep caisson II are joined together and sunk to the matching level with the shallow caisson III. The deep caisson II and the shallow caisson III are then connected to form a whole. The excavation is carried out symmetrically and the sinking is even.

[0030] 4) Descend to the elevation (from deep caisson II to the bottom elevation of the retaining wall, from shallow caisson III to the top of the foundation IV), excavate to the elevation, and in order to ensure that the rubber strip VII at the bottom of the cutting edge of shallow caisson III is in close contact with the top surface of foundation IV for initial water stopping, use a water gun to disperse the sand at the bottom of the caisson.

[0031] 5) At the gap between the outer side of the enclosure and the water-stop curtain, jet grouting piles VI are used for local reinforcement and water-stopping.

[0032] 6) At the junction of the bottom of the cutting edge of the shallow caisson III and the top of the foundation IV, sandbags are piled up and then underwater concrete 1 is poured to further seal the leaks and waterproof the area.

[0033] 7) Remove the retaining walls V and VII that separate the deep and shallow caissons.

[0034] This invention addresses the difficulties of sinking and waterproofing the bottom of caissons when construction space is limited. The solution is as follows:

[0035] 1. The caisson reduces structural dimensions and is assembled in sections on-site before sinking. The caisson consists of a deep caisson II and a shallow caisson III. Both caissons are divided into upper and lower sections. The shallow caisson III connects to the deep caisson II on the outer side of the pier cap. See [link / details]. Figure 7 .

[0036] 2. After the retaining system is completed, remove the retaining structure that separates the deep and shallow caissons.

[0037] 3. Add two layers of rubber strips, one hard and one soft, to the cutting edge. The hard rubber strip 2 and the soft rubber strip 3 are connected by bolts 4 to increase the sealing at the bottom. See [link / details]. Figure 8 .

Claims

1. A method for excavation and construction of the retaining structure of the substructure for the reconstruction of existing bridges, characterized in that, Includes the following steps: 1) Jet grouting piles are used as a water-stop curtain on the outside of the enclosure; 2) Lay out and locate the plane position of the retaining structure. Based on the excavation depth and on-site construction space, assemble the irregularly shaped caisson in sections on-site. 3) The irregular caisson consists of a shallow caisson for the pier section and a deep caisson for the foundation section. The deep caisson is inserted into the soil and serves as the retaining part for the foundation construction. The shallow caisson is located on part of the deep caisson and sits on the foundation, serving as the retaining part for the pier construction. The deep caisson is excavated symmetrically and sunk evenly. When it sinks to the adjacent ground elevation, the deep caisson is segmented and sunk to a matching elevation with the shallow caisson, connecting the deep caisson and the shallow caisson to form a whole. The excavation is symmetrical and the sinking is even. 4) Based on the existing bridge elevation and position relationship, the caissons are sunk in sections and matched, and lowered to the elevation, that is, the deep caissons to the bottom elevation of the retaining wall, and the shallow caissons to the top of the pier cap. Excavation is carried out to the elevation. In order to ensure that the rubber strip at the bottom of the cutting edge of the shallow caisson is in close contact with the top surface of the pier cap for initial water stop, water guns are used to disperse the sand at the bottom of the caisson. 5) At the gap between the outer side of the enclosure and the water-stop curtain, jet grouting piles are used for local reinforcement and water-stopping. 6) At the junction of the bottom of the shallow caisson cutting edge and the top of the foundation, sandbags are piled up and then underwater concrete is poured to further seal the leaks and waterproof the area. 7) Remove the retaining wall separating the deep and shallow caissons.

2. The method for excavation and construction of the substructure retaining structure for the reconstruction of existing bridges according to claim 1, characterized in that: In step 2), the lower structure enclosure adopts irregular caissons. According to the existing bridge plan position relationship, the irregular caissons are installed on site in sections to form a whole.

3. The method for excavation and construction of the substructure retaining structure for the reconstruction of existing bridges according to claim 1, characterized in that: Both the deep and shallow caissons are divided into upper and lower sections, with the shallow caisson connecting to the deep caisson on the outer side of the foundation.

4. The method for excavation and construction of the substructure retaining structure for the reconstruction of existing bridges according to claim 1, characterized in that: Add a soft and a hard rubber strip to the cutting edge and connect them with bolts to increase the sealing of the bottom.

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