Supporting structure close to urban elevated deep foundation pit

Abstract

The invention relates to the technical field of foundation pit supporting and water stop construction, in particular to a deep foundation pit supporting structure close to an urban elevated frame, which comprises cast-in-situ bored piles and a TRD construction method wall, the cast-in-situ bored piles are arranged at the boundary position of a deep foundation pit, and the cast-in-situ bored piles surround the periphery of the excavation range of the deep foundation pit. The TRD construction method wall surrounds the periphery of a surrounding area formed by the multiple cast-in-situ bored piles, and supporting structures are arranged on the inner sides of the cast-in-situ bored piles. The supporting structure has the advantages that the supporting structure is high in strength and rigidity, and foundation pit excavation deformation is small; the TRD construction method wall is high in continuity and good in water stopping effect; the supporting structure and the water stop construction machinery are low in height and good in safety; and the construction of the cast-in-situ bored piles and the TRD construction method wall has small influence on settlement and displacement of the existing urban elevated foundation and piers.

Description

Technical Field

[0001] The invention relates to the technical field of foundation pit support and water-stopping construction, in particular to a deep foundation pit support structure close to an urban elevated road. Background Art

[0002] In the reconstruction of urban traffic road network, the method of underpass and overpass is often adopted to form a three-dimensional intersection with existing roads and urban elevated roads. Among them, the foundation pit project in the construction of underpass road is affected by the limited space of adjacent buildings. The distance between the foundation pit and the existing urban elevated foundation and bridge piers is relatively close, and the requirements for the strength of foundation pit support, the waterproof effect of foundation pit, and the prevention of subsidence of surrounding soil and structures during foundation pit excavation are relatively high.

[0003] Traditional urban foundation pit engineering support structures include SMW method piles, underground continuous walls, etc., and water-stop designs include high-pressure rotary jet piles, biaxial cement mixing piles, triaxial cement mixing piles, etc. Traditional foundation pit structure construction requires a large working surface, and hoisting requires tall machinery for auxiliary operations, and there are high safety risks such as overturning of large machinery; traditional high-pressure rotary jet water-stopping is prone to poor water-stopping effect due to poor bite quality, and biaxial and triaxial cement mixing pile machines have high construction safety risks due to their high frame height, and are less suitable for projects close to urban elevated foundations and bridge pier foundation pits.

[0004] Traditional support structure and water-stopping scheme designs have technical problems such as high requirements for working space, poor water-stopping effects, and high safety risks for large machinery operations in projects adjacent to urban elevated foundations and bridge pier pits. Summary of the invention

[0005] The purpose of the present invention is to provide a deep foundation pit support structure adjacent to an urban elevated road based on the above-mentioned deficiencies in the prior art, which ensures the strength of the deep foundation pit support structure adjacent to the urban elevated road, the water-stopping effect of the foundation pit, and the safety of the support structure construction through a combination of bored cast-in-place piles and TRD method walls; and reduces the influence of the support structure, water-stop pile construction, and foundation pit excavation on the settlement and displacement of the existing urban elevated foundation and bridge piers.

[0006] The purpose of the present invention is achieved by the following technical solutions: A deep foundation pit support structure adjacent to an urban elevated road, characterized in that it comprises bored cast-in-place piles and TRD method walls arranged at the boundary position of the deep foundation pit, wherein a plurality of the bored cast-in-place piles are enclosed within the periphery of the excavation range of the deep foundation pit, the TRD method walls are enclosed within the periphery of the enclosed area formed by a plurality of the bored cast-in-place piles, and a supporting structure is arranged on the inner side of the bored cast-in-place piles.

[0007] The inner support structure includes a plurality of supports evenly spaced apart from each other on the inner side of the bored piles along the depth direction of the deep foundation pit.

[0008] The tops of a plurality of bored cast-in-place piles are connected to form an integral structure by arranging a cap beam; along the depth direction of the deep foundation pit, a first support is connected to the cap beam to form a whole.

[0009] The first support is a reinforced concrete support, which is cast with the cap beam as an integral structure.

[0010] The middle parts of the bored cast-in-place piles are connected to form an integral structure by arranging surrounding purlins at intervals; and the supports located below the first support are connected to the surrounding purlins to form an integral structure.

[0011] The support is a steel pipe support.

[0012] The advantages of the present invention are: the supporting structure has high strength and high rigidity, and the deformation of foundation pit excavation is small; the TRD method wall has high continuity and good water-stopping effect; the supporting structure and water-stopping construction machinery are low in height and have good safety; the bored cast-in-place piles and TRD method wall construction have little effect on the settlement and displacement of existing urban elevated foundations and bridge piers. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 It is a plan view of the present invention (first support); Figure 2 It is a plan view of the present invention (second support); Figure 3 It is a schematic elevation view of the present invention. Implementation

[0014] The features of the present invention and other related features are further described in detail below through embodiments in conjunction with the accompanying drawings to facilitate understanding by those skilled in the art: like Figure 1-3 As shown, the marks 1-6 in the figure respectively represent: bored cast-in-place piles 1, TRD method wall 2, cap beam 3, reinforced concrete support 4, steel pipe support 5, and surrounding purlin 6.

[0015] Example: Figures 1 to 3 As shown, in this embodiment, the supporting structure of the deep foundation pit adjacent to the urban elevated road includes bored cast-in-place piles 1 and TRD method walls 2, wherein a plurality of bored cast-in-place piles 1 are arranged along the excavation boundary range of the deep foundation pit and form support for the deep foundation pit. The TRD method wall 2 is arranged outside the bored cast-in-place piles 1 and surrounds a plurality of bored cast-in-place piles 1, and the TRD method wall 2 serves as an external water stop for the bored cast-in-place piles 1 to improve the water stop effect of the foundation pit.

[0016] Specifically, combined Figures 1 to 3 As shown, three supports are arranged along the depth direction of the deep foundation pit on the inner side of the bored pile 1, including a first support (reinforced concrete support 4) flush with the ground and two supports (steel pipe supports 5) arranged below the first support. The three supports 4 are evenly spaced to resist the soil pressure outside the pit.

[0017] In this embodiment, the tops of several bored cast-in-place piles 1 are connected by a cap beam 3 to form an integral structure. The cap beam 3 is a reinforced concrete cap beam to ensure the integrity of the several bored cast-in-place piles 1, thereby further ensuring the strength and stability of the support structure. The reinforced concrete support 4 as the first support is connected to the cap beam 3 to form an integral structure, and the two are cast at the same time. The pile body of the bored cast-in-place pile 1 is used to resist the lateral displacement of the soil in the deep foundation pit, and the bored cast-in-place pile 1, the cap beam 3 and the reinforced concrete support 4 are rigidly connected to resist the lateral displacement of the top of the deep foundation pit.

[0018] The middle part of several bored piles 1 is connected into an integral structure through a purlin 6. The arrangement position of the purlin 6 matches the second support and the third support. The steel pipe support 5 as the second support and the third support is fixedly connected to the purlin 6 to resist the lateral displacement of the middle part of the deep foundation pit. During construction, a layered, first support and then excavation construction process is adopted. Excavation is stopped to 500mm (support installation space) below the second support, and the purlin 6 and steel pipe support 5 are constructed. The gap between the purlin 6 and the bored pile 1 is filled and compacted with C20 plain concrete to ensure that the force of the purlin is evenly transmitted to the pile body.

[0019] TRD method wall 2 is constructed by special soil cutting, mixing and spraying machinery, with a maximum height of 12m. It forms a cement soil continuous wall by cutting soil, mixing and spraying to replace soil. TRD method wall 2 is constructed after the construction of bored pile 1 of the supporting structure is completed and reaches the design strength. There is no gap between TRD method wall 2 and bored pile 1. TRD method wall 2 forms an integral body along the periphery of bored pile 1 outside the foundation pit. Mechanical steering and 500mm overlap are used at the corners to ensure the continuity of cement soil at the joints.

[0020] During the specific implementation of this embodiment: bored piles can adopt a mud wall protection hole forming process, by controlling the mud specific gravity to ensure the stability of the hole wall, reduce the impact of hole wall collapse during pile hole construction on surrounding soil and buildings; the pile driver frame height is low, and the construction is safer.

[0021] Although the above embodiments have described in detail the concepts and embodiments of the present invention with reference to the accompanying drawings, ordinary technicians in this field can recognize that various improvements and changes can still be made to the present invention without departing from the scope of the claims, so they are not described one by one here.

Claims

1. A deep foundation pit support structure close to an urban elevated road, characterized by: It includes bored cast-in-place piles and TRD method walls arranged at the boundary position of the deep foundation pit, wherein a plurality of the bored cast-in-place piles are enclosed within the periphery of the excavation range of the deep foundation pit, the TRD method wall is enclosed within the periphery of the enclosed area formed by the bored cast-in-place piles, and a supporting structure is arranged on the inner side of the bored cast-in-place piles.

2. The deep foundation pit support structure adjacent to the urban elevated road according to claim 1 is characterized by: The inner support structure includes a plurality of supports evenly spaced apart from each other on the inner side of the bored piles along the depth direction of the deep foundation pit.

3. The deep foundation pit support structure adjacent to the urban elevated road according to claim 2 is characterized by: The tops of a plurality of bored cast-in-place piles are connected to form an integral structure by arranging a cap beam; along the depth direction of the deep foundation pit, a first support is connected to the cap beam to form a whole.

4. The deep foundation pit support structure adjacent to the urban elevated road according to claim 3 is characterized by: The first support is a reinforced concrete support, which is cast with the cap beam as an integral structure.

5. The deep foundation pit support structure adjacent to the urban elevated road according to claim 2 is characterized by: The middle parts of the bored cast-in-place piles are connected to form an integral structure by arranging surrounding purlins at intervals; and the supports located below the first support are connected to the surrounding purlins to form an integral structure.

6. The deep foundation pit support structure adjacent to an urban elevated highway according to claim 5, characterized in that: The support is a steel pipe support.

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