Foundation pit enclosure structure combining bored lock pile, underground continuous wall and cast-in-place pile

Abstract

The application discloses a foundation pit enclosure structure combining a drilled-inclined pile, a diaphragm wall and a cast-in-place pile, which is arranged only around the foundation pit by organically combining the drilled-inclined pile, the diaphragm wall and the cast-in-place pile, compared with a traditional inner support component which needs to cover the whole foundation pit, so that the inner space of the foundation pit is greatly saved. This makes the subsequent foundation pit excavation operation more smooth and efficient, reduces the construction obstruction caused by the occupation of the inner support component, improves the construction efficiency, shortens the engineering construction period, and reduces the time cost.

Description

Technical Field

[0001] This utility model relates to the field of foundation pit retaining structure technology, specifically a foundation pit retaining structure that combines bored interlocking piles, underground continuous walls and cast-in-place piles. Background Technology

[0002] Currently, in the construction of foundation pit excavation, in order to prevent the soil from overturning into the pit, a diaphragm wall retaining structure needs to be constructed before excavation. Then, the soil is excavated downwards within the retaining structure. In order to ensure the strength of the diaphragm wall itself during the soil excavation process and to balance the pressure of the soil on the side walls of the foundation pit on the diaphragm wall, it is also necessary to construct concrete internal support components between the diaphragm walls before excavation can continue. However, the existing internal support components need to cover the entire area of ​​the foundation pit. Although they can play an effective supporting role, they occupy most of the space in the foundation pit and will affect the subsequent excavation work. At the same time, the diaphragm wall is composed of several unit trench segments, and water leakage is prone to occur at its joints, which will also have varying degrees of impact on the construction inside the foundation pit. Summary of the Invention

[0003] The purpose of this utility model is to provide a foundation pit retaining structure that combines drilled interlocking piles, diaphragm walls and cast-in-place piles. It can form a stable support by occupying only a small part of the space around the foundation pit. At the same time, the dual structure arrangement of diaphragm walls and drilled interlocking piles can effectively reduce water leakage in the foundation pit, thus solving the problems in the prior art.

[0004] The technical solution adopted by this utility model to solve its technical problem is: a foundation pit retaining structure combining drilled interlocking piles, diaphragm walls, and cast-in-place piles, including a diaphragm wall, with drilled interlocking piles in contact on one side of the diaphragm wall, and a number of cast-in-place piles arranged at intervals on the other side of the diaphragm wall. The drilled interlocking piles include interlocking piles and plain piles. A connecting longitudinal beam is provided at the top of all cast-in-place piles. The connecting longitudinal beam is arranged parallel to the length of the diaphragm wall. A connecting transverse beam is provided between the piles, the diaphragm wall, and the connecting longitudinal beam. The connecting transverse beam is arranged perpendicular to the connecting longitudinal beam. A number of interconnected first reinforcing cages are provided in the diaphragm wall. A second reinforcing cage is provided in the cast-in-place pile. A third reinforcing cage is provided in the piles. A first connecting bar is provided between the first reinforcing cage and the connecting transverse beam. A second connecting bar is provided between the second reinforcing cage and the connecting longitudinal beam. A third connecting bar is provided between the third reinforcing cage and the connecting transverse beam. The connecting longitudinal beam contains a fourth reinforcing cage arranged along its length, which is welded and fixed to the second connecting bar. The connecting transverse beam contains a fifth reinforcing cage arranged along its length, with one end welded and fixed to the first and third connecting bars, and the other end welded and fixed to the fourth reinforcing cage via the fourth connecting bar. Corresponding to the position of each connecting transverse beam, the connecting longitudinal beam has matching recessed grooves, and the inner circumference of each groove is roughened. Both sides of the connecting transverse beam have lapped flanges along their length. The cross-section of the connecting transverse beam is convex, and embedded bars are provided on the outer surface of the lapped flanges. Diagonal braces are provided between adjacent connecting transverse beams, with the spaced-apart diagonal braces arranged parallel to each other, located below the lapped flanges. The cast-in-place piles and grouting piles are arranged correspondingly, with the diameter of the cast-in-place piles being larger than that of the plain piles. The width of the connecting transverse beam is one-third to one-half the diameter of the cast-in-place pile.

[0005] The positive effects of this utility model are as follows: The foundation pit retaining structure combining bored interlocking piles, diaphragm walls, and cast-in-place piles organically integrates these components and arranges them only around the perimeter of the foundation pit. Compared to traditional internal support components that need to cover the entire foundation pit area, this significantly saves internal space. This allows subsequent foundation pit excavation work to proceed more smoothly and efficiently, reduces construction obstacles caused by the space occupied by internal support components, improves construction efficiency, shortens the project duration, and reduces time costs.

[0006] The diaphragm wall and the bored interlocking piles work together to form a double-structure protection, which effectively reduces water leakage in the foundation pit. This multi-layered anti-leakage design provides a dry environment for construction in the foundation pit, avoids problems such as water accumulation and soil softening caused by water leakage, ensures construction quality and the safety of construction personnel, and also reduces the additional costs and workload caused by water leakage treatment in the later stage.

[0007] The cast-in-place piles are connected by longitudinal beams to form a whole, and the underground continuous wall, bored interlocking piles and cast-in-place piles are connected by transverse beams to form a whole. This makes the entire foundation pit retaining structure an organic force system, which can effectively balance the pressure of the foundation pit sidewall soil on the structure, greatly improve the bearing capacity and deformation resistance of the foundation pit retaining structure, and ensure the safety and stability of the foundation pit construction process. Attached Figure Description

[0008] Figure 1 This is a three-dimensional structural schematic diagram of the present invention; Figure 2 This is the front view of this utility model; Figure 3 yes Figure 2 Top view; Figure 4 yes Figure 2 The right view; Figure 5 yes Figure 2 A magnified view of part of I; Figure 6 yes Figure 4 A magnified view of part II; Figure 7 This is a schematic diagram showing the location of this utility model within the foundation pit. Detailed Implementation

[0009] This utility model describes a foundation pit retaining structure that combines bored interlocking piles, diaphragm walls, and cast-in-place piles, such as... Figure 1-4 As shown, the structure includes a diaphragm wall 1, with bored interlocking piles in contact on one side of the diaphragm wall 1. The bored interlocking piles are located on the outer side of the foundation pit to be excavated. On the other side of the diaphragm wall 1, there are several spaced cast-in-place piles 2. The cast-in-place piles 2 are located near the periphery of the foundation pit sidewall and occupy only a small part of the space around the foundation pit, which can minimize the interference with the subsequent foundation pit excavation.

[0010] The bored interlocking piles include interlocking piles 3 and plain piles 4. The interlocking piles 3 can effectively improve the strength of the overall structure, while the plain piles 4 can fill the gaps between the interlocking piles 3. While ensuring strength, the amount of reinforcement is reduced, thereby saving costs. The interlocking piles 3 and plain piles 4 form an integrated bored interlocking pile. Combined with the double structure of the underground continuous wall 1, it can effectively reduce the occurrence of water leakage in the foundation pit.

[0011] To enhance the connection strength between the bored piles, diaphragm wall 1, and cast-in-place piles 2 in the retaining structure, a connecting longitudinal beam 5 is provided at the top of all cast-in-place piles 2. The connecting longitudinal beam 5 is arranged parallel to the length of the diaphragm wall 1, connecting all cast-in-place piles 2 into a single unit. A connecting transverse beam 6 is provided between the bored piles 3, diaphragm wall 1, and connecting longitudinal beam 5, arranged perpendicular to the connecting longitudinal beam 5. Under the connection of the connecting longitudinal beam 5 and connecting transverse beam 6, the cross-section of the foundation pit retaining structure forms an "n"-shaped integral structure, creating an organic force-bearing system that enhances its strength and resistance to deformation.

[0012] Several interconnected first steel cages 7 are installed within the diaphragm wall 1, second steel cages 8 are installed within the cast-in-place piles 2, and third steel cages 9 are installed within the cast-in-place piles 3. The first steel cages 7, second steel cages 8, and third steel cages 9, as the internal framework of the structure, are all arranged vertically. To achieve the interconnection of the internal frameworks between the structures, first connecting bars 10 are provided between the first steel cages 7 and the connecting crossbeams 6, second connecting bars 11 are provided between the second steel cages 8 and the connecting longitudinal beams 5, and third connecting bars 12 are provided between the third steel cages 9 and the connecting crossbeams 6.

[0013] Before excavating the foundation pit, the aforementioned retaining structure is constructed by first excavating a trench around the perimeter of the pit to be excavated, providing installation space for the diaphragm wall 1. After the trench is completed, continuous interlocking holes are drilled on the outside of the pit, connecting the holes to the trench. Several holes are drilled at intervals on the inside of the pit. After the trench and holes are completed, several first reinforcing cages 7 are placed into the trenches, third reinforcing cages 9 are placed at intervals into the continuously interlocking holes, and second reinforcing cages are placed into the interval-arranged holes. Grouting and curing are then performed to construct the diaphragm wall 1 and the drilled interlocking... After the curing of the piles and cast-in-place piles 2, the concrete at the top of the cast-in-place piles 2 is removed to expose the second connecting bar 11. Then, a formwork structure connecting longitudinal beam 5 is erected on top of all the cast-in-place piles 2. After the construction of the connecting longitudinal beam 5 is completed, the concrete at the top of the underground continuous wall 1 is removed to expose the first connecting bar 10. The concrete at the top of the pile 3 is removed to expose the third connecting bar 12. Then, a formwork structure connecting cross beam 6 is erected between the pile 3, the underground continuous wall 1 and the connecting longitudinal beam 5 to form an integrated foundation pit retaining structure. Subsequently, the soil can be excavated inside the retaining structure.

[0014] Furthermore, in order to achieve the interconnection of the internal skeletons of each structure, such as Figure 5 and Figure 6As shown, the connecting longitudinal beam 5 is provided with a fourth reinforcing cage 13 arranged along the length direction, and the fourth reinforcing cage 13 is welded and fixed to the second connecting bar 11. The connecting transverse beam 6 is provided with a fifth reinforcing cage 14 arranged along the length direction. One end of the fifth reinforcing cage 14 is welded and fixed to the first connecting bar 10 and the third connecting bar 12, and the other end of the fifth reinforcing cage 14 is welded and fixed to the fourth reinforcing cage 13 through the fourth connecting bar 15. When constructing the connecting beam using formwork, the corresponding reinforcing cages can be placed inside the formwork, and the reinforcing cages can be welded and fixed to the connecting bars in advance. Subsequently, concrete can be poured into the formwork to form the connecting longitudinal beam 5 and the connecting transverse beam 6, which are stably connected between the components.

[0015] By installing different steel cages within each structural component and welding them together using first connecting bars 10, second connecting bars 11, third connecting bars 12, and fourth connecting bars 13, a robust steel reinforcement connection system is formed. This connection method ensures the transfer of force between structural components, enabling the entire enclosure structure to work collaboratively under load, fully utilizing the load-bearing capacity of each part, further enhancing the overall integrity and stability of the structure, and effectively preventing structural damage and safety accidents caused by weak connections.

[0016] Furthermore, corresponding to the positions of each connecting crossbeam 6, a matching recessed groove 16 is provided on the connecting longitudinal beam 5, and the inner circumferential surface of each recessed groove 16 is roughened. The recessed groove 16 not only provides a positioning basis for the construction of the connecting crossbeam 6, but also effectively increases the contact area between the connecting crossbeam 6 and the connecting longitudinal beam 5, improving the connection stability between them. The roughening treatment of the inner circumferential surface increases the friction and adhesion between the connecting crossbeam 6 and the connecting longitudinal beam 5, improving the strength and reliability of the connection node.

[0017] Furthermore, the retaining structure does not need to be demolished after the foundation pit excavation is completed, and it serves as part of the building structure within the foundation pit. In order to allow each connecting beam 6 at the top of the retaining structure to form a floor slab structure within the foundation pit, both sides of the connecting beam 6 in the length direction are provided with overlapping flanges 17. The cross-section of the connecting beam 6 is convex. Matching cover plates can be laid between the overlapping flanges 17 of adjacent connecting beams 6 to form a floor slab structure with the top flush with the connecting beam 6. The cast-in-place piles 2 can form the column structure inside the building. To improve the connection stability between the overlapping cover plates and the connecting beams 6, pre-embedded bars 18 are provided on the outer surface of the overlapping flanges 17. Pre-embedded holes that match the pre-embedded bars 18 can be opened on the cover plates.

[0018] Furthermore, diagonal braces 19 are provided between adjacent connecting beams 6, and the diagonal braces 19 are arranged in parallel with each other. The diagonal braces 19 are located on the lower side of the overlapping folded edge 17. The diagonal braces 19 provide additional lateral support to the connecting beams 6, effectively resisting the lateral pressure of the soil on the side wall of the foundation pit on the connecting beams, preventing deformation and displacement of the connecting beams, and ensuring the safety and stability of the entire retaining structure.

[0019] Furthermore, the cast-in-place piles 3 and 2 are arranged correspondingly, with the diameter of the cast-in-place piles 3 being larger than that of the plain piles 4, and the width of the connecting beam 6 being one-third to one-half the diameter of the cast-in-place piles 3. This reasonable design proportion allows the structural components to work together better, fully utilizing their respective advantages. While ensuring structural strength and stability, it optimizes material usage, reduces project costs, and also facilitates operation and installation during construction, improving feasibility and efficiency.

[0020] The technical solution of this utility model is not limited to the scope of the embodiments described herein. All technical contents not described in detail herein are publicly known technologies.

Claims

1. A foundation pit retaining structure combining bored interlocking piles, diaphragm walls, and cast-in-place piles, characterized in that: The structure includes a diaphragm wall (1), with interlocking drilled piles on one side of the diaphragm wall (1) and several spaced cast-in-place piles (2) on the other side. The interlocking drilled piles include interlocking piles (3) and plain piles (4). All cast-in-place piles (2) are topped with connecting longitudinal beams (5). The connecting longitudinal beams (5) are arranged parallel to the length of the diaphragm wall (1). Connecting crossbeams (6) are provided between the piles (3), the diaphragm wall (1) and the connecting longitudinal beams (5). The connecting beam (6) is arranged perpendicularly to the connecting longitudinal beam (5). Several interconnected first steel cages (7) are provided in the underground continuous wall (1), the second steel cage (8) is provided in the cast-in-place pile (2), and the third steel cage (9) is provided in the pile (3). The first connecting bar (10) is provided between the first steel cage (7) and the connecting beam (6), the second connecting bar (11) is provided between the second steel cage (8) and the connecting longitudinal beam (5), and the third connecting bar (12) is provided between the third steel cage (9) and the connecting beam (6).

2. The foundation pit retaining structure combining bored interlocking piles, diaphragm walls, and cast-in-place piles as described in claim 1, characterized in that: The connecting longitudinal beam (5) is provided with a fourth steel cage (13) arranged along the length direction. The fourth steel cage (13) is welded and fixed to the second connecting bar (11). The connecting transverse beam (6) is provided with a fifth steel cage (14) arranged along the length direction. One end of the fifth steel cage (14) is welded and fixed to the first connecting bar (10) and the third connecting bar (12). The other end of the fifth steel cage (14) is welded and fixed to the fourth steel cage (13) through the fourth connecting bar (15).

3. The foundation pit retaining structure combining bored interlocking piles, diaphragm walls, and cast-in-place piles as described in claim 1, characterized in that: Corresponding to the position of each connecting crossbeam (6), a matching recessed groove (16) is provided on the connecting longitudinal beam (5), and the inner circumferential surface of each recessed groove (16) is roughened.

4. The foundation pit retaining structure combining bored interlocking piles, diaphragm walls, and cast-in-place piles as described in claim 1, characterized in that: Both sides of the connecting beam (6) along its length are provided with overlapping flanges (17). The cross section of the connecting beam (6) is convex. Embedded bars (18) are provided on the outer surface of the overlapping flanges (17). Diagonal braces (19) are provided between adjacent connecting beams (6). The diagonal braces (19) are arranged in parallel. The diagonal braces (19) are located on the lower side of the overlapping flanges (17).

5. The foundation pit retaining structure combining bored interlocking piles, diaphragm walls, and cast-in-place piles as described in claim 1, characterized in that: The cast-in-place piles (3) and the grouting piles (2) are arranged in a corresponding manner. The diameter of the cast-in-place piles (3) is larger than that of the plain piles (4). The width of the connecting beam (6) is one-third to one-half the diameter of the cast-in-place piles (3).

Images