An underground space frame structure and its construction method

Abstract

This invention discloses an underground space frame structure and its construction method, belonging to the field of building construction. It includes vertical support piles and multiple layers of horizontal members. The vertical support piles consist of a vertically arranged pile body located within a pre-formed pile hole before excavation. The pile body comprises an upper pile body and a lower pile body; the upper pile body is a cuboid prism, and the lower pile body is a cylinder. An enlarged section exists between the upper and lower pile bodies, with a cross-sectional dimension larger than that of the upper and lower pile bodies. The upper pile body, the enlarged section, and the lower pile body are sequentially arranged from top to bottom within the pile hole, aligning with their central axes and forming a single unit. During the excavation of the foundation pit, the multiple layers of horizontal members are constructed layer by layer from top to bottom and connected to the vertical support piles. This invention employs a top-down reverse construction sequence, eliminating the need for a foundation pit in the underground space construction and scaffolding for beam and slab construction, significantly reducing resource input, shortening the construction period, and improving safety.

Description

Technical Field

[0001] This invention relates to the field of building construction, and in particular to an underground space frame structure and its construction method. Background Technology

[0002] Existing underground spaces, such as parking garages, are mostly constructed using a frame structure, consisting of rectangular columns, independent foundations, and a waterproof base slab. Column construction is completed after the independent foundations and waterproof slab are finished, involving the binding of reinforcing bars, the erection of formwork, and the pouring of concrete layer by layer.

[0003] Traditional underground space frame structures require the construction of a foundation layer, waterproofing, and waterproofing liner after the foundation pit is excavated, followed by the construction of independent foundations, then the erection of column formwork, the binding of reinforcing bars, and the pouring of column concrete, layer by layer. This process is complex, inefficient, involves many steps, and results in significant material waste. Summary of the Invention

[0004] This invention provides an underground space frame structure and its construction method, which adopts a top-down reverse construction sequence. The construction of underground space support piles does not require a foundation pit, and the construction of beams and slabs does not require scaffolding, which greatly reduces resource input, shortens the construction period, and improves safety.

[0005] The technical solution provided by this invention is as follows:

[0006] An underground space frame structure includes vertical support piles and multiple layers of horizontal members connected to the vertical support piles. A plurality of the vertical support piles are arranged in a column grid according to their designed positions, wherein:

[0007] The vertical support pile is a reinforced concrete bored pile, comprising a vertically arranged pile body located within a pre-formed pile hole before excavation of the foundation pit. The pile body is formed by a reinforcing cage and concrete within the pile hole. The pile body includes an upper pile body and a lower pile body. The upper pile body is a cuboid prism, and the lower pile body is a cylinder. An enlarged section is provided between the upper and lower pile bodies, and the cross-sectional dimension of the enlarged section is larger than that of the upper and lower pile bodies. The upper pile body, the enlarged section, and the lower pile body are arranged sequentially from top to bottom within the pile hole with their central axes aligned, and are integrally formed.

[0008] The multi-layered horizontal members are used to be constructed layer by layer from top to bottom and connected to the vertical support piles during the excavation of the foundation pit.

[0009] Furthermore, the multi-layer horizontal component includes a waterproof membrane and at least one layer of horizontal beams and floor slabs. The waterproof membrane is located on the bottom surface of the excavated foundation pit. The top surface of the expanded section is flush with the top surface of the waterproof membrane. The expanded section and the lower pile body are located below the top surface of the waterproof membrane, and the upper pile body is located above the top surface of the waterproof membrane.

[0010] The at least one layer of horizontal beams and floor slabs are located on the upper pile body of the vertical support piles above the waterproofing slab.

[0011] Furthermore, the expanded section includes an upper frustum and a lower cylinder, the central axes of the upper frustum and the lower cylinder coincide, the diameter of the upper frustum gradually increases from top to bottom, the bottom diameter of the upper frustum is equal to the top diameter of the lower cylinder, and the thickness of the waterproof membrane is the same as the thickness of the upper frustum.

[0012] Furthermore, the rectangular cross-section of the upper pile body is inscribed within the rectangle formed by the projection of the top surface of the upper frustum, which is within the circle of the top surface of the upper frustum. The circular cross-section of the lower pile body is inscribed within the rectangle formed by the projection of the top surface of the upper frustum, which is within the rectangle formed by the projection of the upper pile body.

[0013] Furthermore, the reinforcing cage includes longitudinal reinforcing bars and transverse stirrups, wherein the longitudinal reinforcing bars are arranged vertically and run along the length of the pile body.

[0014] Furthermore, the longitudinal reinforcing bars are arranged in a rectangular shape within the upper pile body according to the rectangular cross-section of the upper pile body, and the longitudinal reinforcing bars are arranged in a circular shape within the lower pile body according to the circular cross-section of the lower pile body. The portion of the longitudinal reinforcing bars within the expanded section is an inwardly bent transition zone.

[0015] Furthermore, taking the center point of the rectangular cross-section of the upper pile body as the center, the longitudinal reinforcement closer to the outside bends inward to a greater degree, while the longitudinal reinforcement at the point where the circular cross-section of the lower pile body is tangent to the rectangular cross-section of the upper pile body does not bend.

[0016] Furthermore, the longitudinal reinforcement bars on the stress-bearing side of the pile body and on the opposite side of the stress-bearing side are reinforced.

[0017] Furthermore, the transverse stirrups are densely arranged in the bottom area of ​​the upper pile body, the top area of ​​the lower pile body, and the entire area of ​​the expanded section.

[0018] A construction method for an underground space frame structure, the method comprising:

[0019] S1: Before the foundation pit is excavated, the pile holes are constructed at the designed locations of the vertical support piles using a drilling rig;

[0020] S2: After the pile hole construction is completed, the tied steel cage is lowered into the pile hole and concrete is poured into the pile hole to realize the construction of the vertical support pile. Multiple vertical support piles form a column network.

[0021] S3: After the concrete has cured, excavate the foundation pit at the designed location.

[0022] S4: During the excavation of the foundation pit, horizontal beams and floor slabs are constructed layer by layer from top to bottom on the upper pile body of the vertical support piles, and construction access passages are reserved on each floor slab.

[0023] S5: After the foundation pit is excavated, a waterproof membrane is constructed on the bottom surface of the foundation pit, and the top surface of the expanded section of the vertical support pile is flush with the top surface of the waterproof membrane. The expanded section and the lower pile body are located below the top surface of the waterproof membrane, and the upper pile body is located above the top surface of the waterproof membrane.

[0024] S6: Block off the construction access passages reserved on each floor slab.

[0025] The present invention has the following beneficial effects:

[0026] This invention replaces independent foundations with expanded sections and lower pile bodies of vertical support piles. Through ground-driven, integrated, and efficient construction, it directly forms a load-bearing component integrating an upper rectangular and lower circular foundation with columns. This invention achieves integrated, mechanized, and rapid construction of vertical load-bearing components, providing a new vertical structure construction technology for the prefabricated and industrialized development of underground structures. Furthermore, unlike traditional underground parking garage construction, this invention changes the traditional bottom-up construction method for underground spaces, adopting a top-down reverse construction sequence. Through effective connection of horizontal components at each level, it forms an underground space frame structure. Underground space construction requires no foundation pit or support, saving significant investment in beam, slab, column scaffolding, formwork, and other measures compared to traditional top-down construction, greatly improving efficiency and avoiding safety hazards associated with elevated formwork. Attached Figure Description

[0027] Figure 1 This is a schematic diagram of an underground space frame structure according to the present invention (horizontal beams and floor slabs of each floor are omitted);

[0028] Figure 2 This is a schematic diagram of a vertical support pile;

[0029] Figure 3-5 This is a schematic diagram illustrating the construction process of an underground space frame structure according to the present invention;

[0030] Figure 6This is a schematic diagram showing the connection between the waterproof membrane and the vertical support piles;

[0031] Figure 7 This is a cross-sectional view of the reinforcement of the upper pile body;

[0032] Figure 8 This is a cross-sectional view of the reinforcement of the lower pile body;

[0033] Figure 9 This is a transition section diagram of the longitudinal reinforcement;

[0034] Figure 10 This is a schematic diagram showing the projection of the upper and lower pile bodies onto the top surface of the expanded section;

[0035] Figure 11 This is a schematic diagram showing the transition of longitudinal reinforcement and the densification of transverse stirrups. Detailed Implementation

[0036] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with the accompanying drawings and specific embodiments.

[0037] This invention provides an underground space frame structure, such as... Figure 1-11 As shown, the underground space frame structure includes vertical support piles 100 and multi-layer horizontal members 200 connected to the vertical support piles 100. Multiple vertical support piles 100 are arranged in their designed positions to form a column grid.

[0038] The vertical support pile 100 is a reinforced concrete bored pile, comprising a pile body 1 vertically arranged within a pre-formed pile hole before excavation of the foundation pit. The pile body 1 is formed by a reinforcing cage and concrete located within the pile hole, wherein:

[0039] like Figure 2 As shown, the pile body 1 includes an upper pile body 2 and a lower pile body 3. The upper pile body 2 is a cuboid prism with a rectangular cross-section, preferably a square. The lower pile body 3 is a cylinder with a circular cross-section.

[0040] There is an enlarged section 4 between the upper pile body 2 and the lower pile body 3. The cross-sectional dimensions of the enlarged section 4 are larger than the cross-sectional dimensions of the upper pile body 2 and the lower pile body 3.

[0041] The upper pile body 2, the expanded section 4, and the lower pile body 3 are arranged sequentially from top to bottom in the pile hole with their central axes coinciding, and are formed as a whole.

[0042] The aforementioned multi-layered horizontal members 200 are used to connect to the column network composed of vertical support piles 100, constructed layer by layer from top to bottom during the excavation of the foundation pit. That is, the present invention first constructs multiple vertical support piles 100 with rectangular upper and circular lower cross-sections as load-bearing components through ground piling. Then, it excavates layer by layer, constructing horizontal members such as beams and slabs from top to bottom to connect with these load-bearing components, forming a frame structure for the underground space, such as... Figure 3-5 As shown.

[0043] This invention constructs a reinforced concrete bored pile in three parts, forming a pile body with a variable cross-section. The upper pile body 2 has a rectangular cross-section and functions as a column in the underground space, facilitating connection with horizontal components to form a unified structure. As part of the structure, it acts as a column in the underground structure, bearing vertical forces. The middle and lower expanded section 4 functions as a pile cap, and below the expanded section 4 is the lower pile body 3 with a circular cross-section, which is convenient and quick to construct, effectively saving materials and construction time. The expanded section 4 and the lower pile body 3 are embedded in the foundation of the excavated pit, equivalent to a pile foundation, replacing an independent foundation. Through the effective connection of the horizontal components 200 at each level with the vertical support piles 100, a novel underground space frame structure system is formed.

[0044] The core of this invention is the use of an integrated column-pile vertical support structure. The columns in the underground space have rectangular cross-sections, with the lower expanded section and the circular cross-section piles extending deep into the bottom of the underground space as the foundation for the vertical structure. The expanded section 4 and lower pile body 3 of the vertical support pile 100 replace independent foundations. Through ground-driven, integrated, and efficient construction, a load-bearing structure integrating the upper rectangular and lower circular foundations with the columns is directly formed. This invention achieves integrated, mechanical, and rapid construction of vertical load-bearing components, providing a new vertical structure construction technology for the prefabricated and industrialized development of underground structures. Furthermore, this invention differs from traditional underground parking garage construction, changing the traditional bottom-up construction method for underground spaces. It adopts a top-down reverse construction sequence, effectively connecting the horizontal components of each layer to form an underground space frame structure. Underground space construction requires no foundation pit or support, saving the significant investment in beam, slab, column scaffolding, formwork, and other measures required in traditional top-down construction, greatly improving efficiency and avoiding safety hazards associated with elevated formwork.

[0045] The aforementioned multi-layer horizontal structure 200 may include a waterproof membrane 201 and at least one layer of horizontal beams 202 and floor slabs. The waterproof membrane 201 is located on the bottom surface 14 of the excavated foundation pit 13. The top surface of the expanded section 4 is flush with the top surface of the waterproof membrane 201. The expanded section 4 and the lower pile body 3 are located below the top surface of the waterproof membrane 201, and the upper pile body 2 is located above the top surface of the waterproof membrane 201. At least one layer of horizontal beams 202 and floor slabs are sequentially located on the upper pile body 2 of the vertical support piles 100 above the waterproof membrane 201.

[0046] In this invention, the expanded section 4 functions as a support platform and is easily connected to the waterproof membrane 201. It utilizes the rigidity of the waterproof membrane 201, saves on formwork and other construction measures, and greatly improves efficiency.

[0047] As an example, such as Figure 2 As shown, the expanded section 4 may include an upper frustum 5 and a lower cylinder 6. The central axes of the upper frustum 5 and the lower cylinder 6 coincide. The diameter of the upper frustum 5 gradually increases from top to bottom, and the diameter transitions. The bottom diameter of the upper frustum 5 is equal to the top diameter of the lower cylinder 6.

[0048] Correspondingly, the thickness of the waterproof membrane 201 can be the same as the thickness of the upper frustum 5, so that the upper frustum 5 is entirely located within the waterproof membrane 201, and the lower cylindrical body 6 is located below the waterproof membrane 201, such as... Figure 6 As shown.

[0049] Specifically, the rectangular cross-section of the upper pile body 2, projected onto the top surface of the upper frustum 5, forms a rectangle 7 which is inscribed within the circle 8 on the top surface of the upper frustum 5. Similarly, the circular cross-section of the lower pile body 3, projected onto the top surface of the upper frustum 5, forms a circle 9 which is inscribed within the rectangle 7 formed by the projection of the upper pile body 2. Figure 10 As shown.

[0050] In this invention, such as Figure 7-9 As shown in Figure 11, the reinforcing cage includes longitudinal reinforcing bars 10 and transverse stirrups 11. The longitudinal reinforcing bars 10 are arranged vertically and run continuously along the length of the pile body 1, that is, the number of longitudinal reinforcing bars 10 is the same in the upper pile body 2, the lower pile body 3, and the expanded section 4. Furthermore, the number of longitudinal reinforcing bars 10 and transverse stirrups 11 is reasonably arranged according to the results of mechanical calculations on site.

[0051] Multiple longitudinal reinforcing bars 10 are arranged in a rectangular shape within the upper pile body 2 according to the rectangular cross-section of the upper pile body 2, such as... Figure 7 As shown; multiple longitudinal reinforcing bars 10 are arranged in a circular pattern within the lower pile body 3 according to the circular cross-section of the lower pile body 3, as shown. Figure 8 As shown; the portion of the longitudinal reinforcing bar 10 within the expanded section 4 is a transition zone 12 with inward bending, changing the shape of the longitudinal reinforcing bar 10 to achieve the transition from the upper pile body 2 to the lower pile body 3, as shown. Figure 9 As shown.

[0052] Taking the center point of the rectangular cross-section of the upper pile body 2 as the center, the longitudinal reinforcement 10 closer to the outer edge bends inward to a greater degree. The longitudinal reinforcement 10-1 at the point where the circular cross-section of the lower pile body 3 is tangent to the rectangular cross-section of the upper pile body 2 does not bend. The longitudinal reinforcement at the four corners of the rectangular cross-section of the upper pile body 2 bends to the greatest extent. Figure 9 As shown.

[0053] The longitudinal reinforcement 10-2 on the stress-bearing side of pile 1 and on the opposite side of the stress-bearing side is reinforced, for example, as shown in the figure. Figure 7 , 8 As shown, the upper side of pile 1 is the stress-bearing side (the side that bears the bending moment). Therefore, the longitudinal reinforcement 10-2 is reinforced on the upper and lower sides of the upper pile 2 and the lower pile 3 in the figure. The reinforcement can be achieved by increasing the diameter of the longitudinal reinforcement 10-2 or by increasing the density of the longitudinal reinforcement 10-2.

[0054] In the bottom area of ​​the upper pile body 2, the top area of ​​the lower pile body 3, and the entire area of ​​the expanded section 4, the transverse stirrups 11 are densely arranged to enhance the load-bearing performance, such as... Figure 11 As shown.

[0055] This invention also provides a construction method for an underground space frame structure, comprising the following steps:

[0056] S1: Before the foundation pit is excavated, the pile holes are constructed at the designed positions of the vertical support piles 100 using a drilling rig.

[0057] During pile hole construction, according to design requirements, there are different cross sections at different depths. The upper cross section is rectangular and is used to form the upper pile body 2. The lower cross section is circular and is used to form the lower pile body 3. The section in between is the enlarged part of the pile hole cross section (referred to as the enlarged part) and is used to form the enlarged body section 4.

[0058] In this invention, the length and side length / diameter of the upper pile body 2 and the lower pile body 3 can be adjusted according to engineering needs, and the diameter and thickness of the expanded section 4 can be adjusted according to engineering needs.

[0059] S2: After the pile hole construction is completed, the tied steel cage is lowered into the pile hole, and concrete is poured into the pile hole to complete the construction of the vertical support piles 100. Multiple vertical support piles 100 form a column grid, such as... Figure 3 As shown.

[0060] S3: After the concrete has cured to the preset strength, excavation of foundation pit 13 will be carried out at the designed location of the foundation pit.

[0061] S4: During the excavation of foundation pit 13, horizontal beams 202 and floor slabs are constructed layer by layer from top to bottom on the upper pile body 2 of vertical support piles 100, such as... Figure 4 , 5 As shown; and construction access channels are reserved on each floor slab.

[0062] When reserving access routes for construction, a floor slab can be left uninstalled at a certain location to serve as the access route.

[0063] S5: After the excavation of the foundation pit 13 is completed, a waterproof membrane 201 is constructed on the bottom surface 14 of the foundation pit 13, ensuring that the top surface of the expanded section 4 of the vertical support pile 100 is flush with the top surface of the waterproof membrane 201. The expanded section 4 and the lower pile body 2 are located below the top surface of the waterproof membrane 201, and the upper pile body 2 is located above the top surface of the waterproof membrane 201. Figure 6 As shown.

[0064] S6: Seal off the construction access passages reserved on each floor slab to realize the construction of the underground space frame structure.

[0065] This invention involves ground construction before excavation of the foundation pit, completing the drilling of the upper circular pile columns, then hoisting the reinforcing cage, pouring concrete, and after it reaches the preset strength, excavating and constructing the garage roof slab, connecting the beams and slabs with the columns. After the beams and slabs reach the predetermined strength, excavation begins, and after reaching the predetermined depth, the next layer of beams and slabs is constructed. After reaching the bottom layer, the foundation layer and waterproofing membrane are constructed.

[0066] This invention contrasts with traditional underground structure construction methods, overcoming the drawbacks of complex, inefficient, and resource-intensive processes. It employs a reverse construction method, starting from the ground level, which improves construction efficiency and saves significant investment in beams, slabs, columns, scaffolding, and formwork. It also avoids the safety hazards associated with elevated formwork, thus efficiently forming vertical support components for the underground space. This significantly reduces resource input, shortens the construction period, and improves safety. This novel approach not only promotes the transformation of foundation pit engineering but also drives advancements in basic theories and design methods, contributing to the intensive development of urban underground space construction. It represents an important direction for implementing the new development philosophy and constructing a new development pattern for underground engineering.

[0067] The above description represents the preferred embodiments of the present invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. An underground space frame structure, characterized in that, It includes vertical support piles and multiple layers of horizontal members connected to the vertical support piles. Multiple vertical support piles are arranged in their designed positions to form a column grid, wherein: The vertical support pile is a reinforced concrete bored pile, comprising a vertically arranged pile body located within a pre-formed pile hole before excavation of the foundation pit. The pile body is formed by a reinforcing cage and concrete within the pile hole. The pile body includes an upper pile body and a lower pile body. The upper pile body is a cuboid prism, and the lower pile body is a cylinder. An enlarged section is provided between the upper and lower pile bodies, and the cross-sectional dimension of the enlarged section is larger than that of the upper and lower pile bodies. The upper pile body, the enlarged section, and the lower pile body are arranged sequentially from top to bottom within the pile hole with their central axes aligned, and are integrally formed. The multi-layered horizontal members are used to be constructed layer by layer from top to bottom and connected to the plane of the upper pile side of the vertical support pile during the excavation of the foundation pit. The multi-layer horizontal structure includes a waterproof slab and at least one layer of horizontal beams and floor slabs. The waterproof slab is located on the bottom surface of the excavated foundation pit. The top surface of the expanded section is flush with the top surface of the waterproof slab. The expanded section and the lower pile body are located below the top surface of the waterproof slab, and the upper pile body is located above the top surface of the waterproof slab. The at least one layer of horizontal beams and floor slabs are connected to the plane of the upper pile side of the vertical support pile above the waterproofing slab; The expanded section includes an upper frustum and a lower cylinder. The central axes of the upper frustum and the lower cylinder coincide. The diameter of the upper frustum gradually increases from top to bottom. The bottom diameter of the upper frustum is equal to the top diameter of the lower cylinder. The thickness of the waterproof membrane is the same as the thickness of the upper frustum. The rectangular cross-section of the upper pile body is inscribed within the rectangle formed by the projection of the top surface of the upper frustum, which is within the circle of the top surface of the upper frustum. The circular cross-section of the lower pile body is inscribed within the rectangle formed by the projection of the top surface of the upper frustum, which is within the rectangle formed by the projection of the upper pile body.

2. The underground space frame structure according to claim 1, characterized in that, The steel cage includes longitudinal steel bars and transverse stirrups, wherein the longitudinal steel bars are arranged vertically and run along the length of the pile body.

3. The underground space frame structure according to claim 2, characterized in that, The longitudinal reinforcing bars are arranged in a rectangular shape within the upper pile body according to the rectangular cross-section of the upper pile body, and the longitudinal reinforcing bars are arranged in a circular shape within the lower pile body according to the circular cross-section of the lower pile body. The portion of the longitudinal reinforcing bars within the expanded section is an inwardly bent transition zone.

4. The underground space frame structure according to claim 3, characterized in that, With the center point of the rectangular cross-section of the upper pile body as the center, the longitudinal steel bars closer to the outside bend inward to a greater degree, and the longitudinal steel bars at the point where the circular cross-section of the lower pile body is tangent to the rectangular cross-section of the upper pile body do not bend.

5. The underground space frame structure according to claim 3, characterized in that, The longitudinal reinforcement bars on the stress-bearing side of the pile and on the opposite side of the stress-bearing side are reinforced.

6. The underground space frame structure according to claim 5, characterized in that, The transverse stirrups are densely arranged in the bottom area of ​​the upper pile body, the top area of ​​the lower pile body, and the entire area of ​​the expanded section.

7. A construction method for an underground space frame structure according to any one of claims 1-6, characterized in that, The method includes: S1: Before the foundation pit is excavated, the pile holes are constructed at the designed locations of the vertical support piles using a drilling rig; S2: After the pile hole construction is completed, the tied steel cage is lowered into the pile hole and concrete is poured into the pile hole to realize the construction of the vertical support pile. Multiple vertical support piles form a column network. S3: After the concrete has cured, excavate the foundation pit at the designed location. S4: During the excavation of the foundation pit, horizontal beams and floor slabs are constructed layer by layer from top to bottom on the upper pile body of the vertical support piles, and construction access passages are reserved on each floor slab. S5: After the foundation pit is excavated, a waterproof membrane is constructed on the bottom surface of the foundation pit, and the top surface of the expanded section of the vertical support pile is flush with the top surface of the waterproof membrane. The expanded section and the lower pile body are located below the top surface of the waterproof membrane, and the upper pile body is located above the top surface of the waterproof membrane. S6: Block off the construction access passages reserved on each floor slab.

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