Foundation pit support device combining concrete and steel beam string

Abstract

This invention provides a foundation pit support device combining concrete and tensioned steel beams. It integrates a concrete support system with tensioned steel beam supports, utilizing a specially designed concrete force distribution and conversion structure and pre-embedded force transmission joint components. It also provides conditions for setting up a prestressed servo structure for the supports. By combining tension steel cables and chordal web members with the steel beam structure to form a self-balancing tensioned beam system, the tension of the steel cables bears the structure's self-weight, reducing the bending stress and deformation of the steel beam structure in the vertical plane. Without significantly increasing the cross-section of the support components, it meets the requirements for continuous and reliable force transmission of the support structure system under large-span, column-free foundation pit support conditions. Furthermore, by setting up a prestressed servo structure for the supports, it limits soil deformation caused by foundation pit excavation to a smaller range, reducing the impact of underground space development on the surrounding environment.

Description

Technical Field

[0001] This invention relates to a foundation pit support device combining concrete and tensioned steel beams. Background Technology

[0002] With the increasing development and improvement of urban rail transit and municipal road networks, underground public facilities such as subway tunnels and municipal road tunnels are now densely distributed in the core urban areas. Due to the scarcity of construction land, the development of underground space within urban areas will accelerate to expand the building area. Consequently, underground space development will increasingly face situations involving crossing underground tunnel structures. Influenced by existing and planned tunnels and other deeply buried important underground municipal facilities, the foundation pit retaining and support structures of underground spaces in urban plots must avoid the underground tunnel structures and their designated construction protection zones. Currently, the space occupied by tunnels in double-track rail transit sections and municipal road tunnels is generally greater than 30m. The required support system for the underground space foundation pit of the urban plot needs to span a span of 30m or more and cannot be equipped with support columns. Since the stress state of the foundation pit support structure members is that of compression-bending members, the out-of-plane bending moment of the support beam under the action of its own weight will increase sharply when the span increases. The combined effect of its own weight and bending moment will greatly reduce the horizontal bearing capacity and stability of the support beam. Due to the limitations of the slenderness ratio and material strength of the existing reinforced concrete support and steel support systems, the cross-section of the support beam members will be greatly increased, making it difficult to meet the requirements of crossing the underground tunnel and forming a reliable horizontal support system for the foundation pit under the condition of selecting economically reasonable component cross-sections. Summary of the Invention

[0003] The purpose of this invention is to provide a foundation pit support device that combines concrete and tensioned steel beams.

[0004] To address the above problems, the present invention provides a foundation pit support device combining concrete and tensioned steel beams, comprising:

[0005] A concrete edge-supported force-transfer structure system is installed on both sides of the area to be crossed, extending to the vertical retaining edge of the foundation pit;

[0006] A central tensioned steel beam support structure system is set above the area to be crossed, connecting the two sides of the concrete side support force transmission structure system;

[0007] The concrete force distribution and conversion structure system includes: a supporting column and a force distribution beam, wherein one end of the force distribution beam is connected to the concrete side support force transmission structure system, and the other end of the force distribution beam is connected to the central tensioned steel beam support structure system; the supporting column serves as a vertical support member for the force distribution beam, one end of the supporting column is connected to the force distribution beam, and the other end of the supporting column is inserted into the soil for support.

[0008] A pre-embedded force transmission joint component is pre-embedded in the force transmission distribution beam and connected to the central tensioned steel beam support structure system;

[0009] The steel support prestressed servo connection component is connected at one end to the central tensioned steel beam support structure system, and at the other end to the force distribution beam through the pre-embedded force transmission joint component.

[0010] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the support columns adopt an integrated driven steel pipe pile structure system, a driven steel pipe concrete pile structure system, a drilled cast-in-place pile internal steel pipe column structure system, a drilled cast-in-place pile internal lattice steel column structure system, a cement mixing pile internal steel pipe column structure system, a cement mixing pile internal lattice steel column structure system, or a cement mixing pile internal precast reinforced concrete column structure system.

[0011] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the force distribution beam may be, but is not limited to, a cast-in-place reinforced concrete beam structure system, a cast-in-place steel-reinforced concrete composite beam structure system, a steel beam structure system, a lattice steel beam structure system, a precast reinforced concrete beam structure system, or a precast steel-reinforced concrete composite beam structure system.

[0012] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the cast-in-place steel-concrete composite beam structure system transmits force to the distribution beam, and the precast steel-concrete composite beam structure system transmits force to the distribution beam. When the support force is small, a horizontal beam-type steel frame is used, and when the support force is large, a horizontal arch-type steel frame is used.

[0013] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the concrete side support force transmission structure system is composed of horizontal, longitudinal, transverse, and diagonal reinforced concrete or steel-reinforced concrete composite structural beams, and a reinforced concrete slab is provided on the top of the concrete side support force transmission structure system.

[0014] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the central tensioned steel beam support structure system includes: a main beam and a tensioned structure, wherein the main beam adopts steel sections without vertical support, steel pipes, or lattice-type steel structure components; the tensioned structure consists of steel cables and web members, with both ends of the steel cables connected to both ends of the main beam, one end of the web members connected to the steel cables through cable clamp nodes, and the other end of the web members connected to the main beam through preset nodes.

[0015] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the steel cables are tensioned and released using automatic tensioning anchors to adjust the cable tension according to different design conditions to meet load requirements.

[0016] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the pre-embedded force transmission joint component includes: an anchor bar welded plate component or a steel conversion welded joint component.

[0017] Furthermore, in the above-mentioned foundation pit support device composed of concrete and tensioned steel beams, the anchor bar welded plate component is used when the force distribution beam is made of reinforced concrete and the pre-embedded force transmission joint component is made of anchor bar welded plate, with the anchor bar embedded in the force distribution beam and the welded plate placed on the surface of the component connecting the force distribution beam and the middle tensioned steel beam support structure system.

[0018] The aforementioned steel conversion welded joint type is used when the force distribution beam adopts a steel-reinforced concrete beam structure, a steel beam structure, or a lattice steel beam structure. The pre-embedded force transmission joint component adopts the steel conversion welded joint type, which is welded to the steel skeleton inside the force distribution beam or the connection side between the steel force distribution beam and the central tensioned steel beam support structure system.

[0019] Furthermore, in the aforementioned foundation pit support device combining concrete and tensioned steel beams, the steel support prestressed servo connection component is used to install a steel support prestressed servo connection component at one or both ends of the central tensioned steel beam support structure system when the foundation pit deformation control requirements are high. The steel support prestressed servo connection component is composed of a servo and a conversion connection component.

[0020] Compared with existing technologies, this invention provides a large-span unsupported foundation pit support system based on a concrete-tensioned steel beam composite structure. It combines a concrete support system with tensioned steel beam supports, utilizing a specially designed concrete force distribution and conversion structure and pre-embedded force transmission joint components. It also provides conditions for setting up a prestressed servo structure for the supports. By combining tension steel cables and cable-stayed web members with the steel beam structure to form a self-balancing tensioned beam system, the tension of the steel cables bears the structure's self-weight, reducing the bending stress and deformation of the steel beam structure in the vertical plane. This achieves the requirement of continuous and reliable force transmission for the support structure system under large-span, column-free foundation pit support conditions without significantly increasing the cross-section of the support components. Furthermore, by setting up a prestressed servo structure for the supports, it limits soil deformation caused by foundation pit excavation to a smaller range, reducing the impact of underground space development on the surrounding environment.

[0021] This invention addresses the current situation where subway tunnels and municipal road tunnels are densely distributed in urban core areas, and urban underground space development will increasingly face situations where it crosses underground tunnel structures. The underground space foundation pit retaining and support structure system needs to avoid the underground tunnel structure and its protection range. The support system in the foundation pit needs to cross a span of 30m or more, making it impossible to install support columns. Existing reinforced concrete support and steel support systems are difficult to meet this requirement due to the limitations of component slenderness ratio and material strength. This invention provides a large-span unsupported foundation pit support system based on a concrete-tensioned steel beam composite structure. It combines a concrete support system with a steel support system, utilizing a specially designed concrete force distribution and conversion structure and pre-embedded force transmission joint components. It also provides conditions for setting up a prestressed servo structure for the support. By combining tension steel cables and chord-supported web members with the steel beam structure to form a self-balancing tensioned beam system, the tension of the steel cables bears the structure's self-weight, reducing the bending stress and deformation of the steel beam structure in the vertical plane. This achieves the requirement of continuous and reliable force transmission for the support structure system under large-span, column-free foundation pit support conditions. Furthermore, by setting up a prestressed servo structure for the support, the soil deformation caused by foundation pit excavation can be limited to a small range, reducing the impact of underground space development on the surrounding environment. Attached Figure Description

[0022] Figure 1 This is a cross-sectional view of the construction of a large-span unsupported foundation pit support system for a concrete-tensioned steel beam composite structure according to an embodiment of the present invention.

[0023] Figure 2 This is a plan view of a large-span unsupported foundation pit support system for a concrete-tensioned steel beam composite structure according to an embodiment of the present invention.

[0024] Figure 3 This is a design drawing of a centrally tensioned steel beam support structure system according to an embodiment of the present invention;

[0025] Figure 4 This is a design drawing of the automatic end tensioning anchor of the present invention;

[0026] Figure 5 This is a design drawing of the automatic tensioning anchor at both ends of the present invention;

[0027] Figure 6 This is a design drawing of the web bar clamp of the present invention;

[0028] Figure 7 This is a design diagram of a concrete force transfer distribution and conversion structure system according to an embodiment of the present invention;

[0029] Figure 8 This is a design drawing of a pre-embedded force transmission joint component according to an embodiment of the present invention;

[0030] Figure 9 This is a design drawing of a steel support prestressed servo connection component according to an embodiment of the present invention;

[0031] The numbers in the diagram are as follows:

[0032] 11. Tensioned beam support; 12. Concrete support; 13. Force distribution beam; 14. Support column; 15. Embedded welding plate; 16. Servo system; 17. Transformation connection component;

[0033] 21. Steel main beam; 22. Steel cable; 23. Web member; 24. Cable clamp; 25. Pre-set node; 26. Stiffening plate; 27. End automatic tensioning anchor; 28. Middle automatic tensioning anchor; 29. ​​Connecting plate;

[0034] 31. Cable anchor plate; 32. Hydraulic chamber partition; 33. Piston; 34. Sensing piston; 35. Stress sensor; 36. Data transmission interface; 37. Oil nozzle; 38. Hydraulic chamber;

[0035] Upper clamping plate 41; lower clamping plate 42; bolt 43; nut 44;

[0036] Arched steel-concrete beam 51; Arched steel 52; Shear stud 53;

[0037] Embedded connector 61; Embedded steel plate 62;

[0038] 71. Steel cable; 72. Cable anchor plate; 73. Hydraulic chamber partition; 74. Oil nozzle; 75. Tensioning piston; 76. Tensioning piston end cable anchor plate; 77. Pressure sensor; 78. Data transmission interface. Detailed Implementation

[0039] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0040] This invention provides a foundation pit support device combining concrete and tensioned steel beams, comprising:

[0041] A concrete edge-supported force-transfer structure system is installed on both sides of the area to be crossed, extending to the vertical retaining edge of the foundation pit;

[0042] A central tensioned steel beam support structure system is set above the area to be crossed, connecting the two sides of the concrete side support force transmission structure system;

[0043] The concrete force distribution and conversion structure system includes: a supporting column and a force distribution beam, wherein one end of the force distribution beam is connected to the concrete side support force transmission structure system, and the other end of the force distribution beam is connected to the central tensioned steel beam support structure system; the supporting column serves as a vertical support member for the force distribution beam, one end of the supporting column is connected to the force distribution beam, and the other end of the supporting column is inserted into the soil for support.

[0044] A pre-embedded force transmission joint component is pre-embedded in the force transmission distribution beam and connected to the central tensioned steel beam support structure system;

[0045] The steel support prestressed servo connection component is connected at one end to the central tensioned steel beam support structure system, and at the other end to the force distribution beam through the pre-embedded force transmission joint component.

[0046] This invention provides a large-span, unsupported foundation pit support system based on a concrete-tensioned steel beam composite structure. It combines a concrete support system with tensioned steel beam supports, utilizing a specially designed concrete force distribution and conversion structure and pre-embedded force transmission joint components. It also provides conditions for setting up a prestressed servo structure for the supports. By combining tension steel cables and cable-stayed web members with the steel beam structure to form a self-balancing tensioned beam system, the tension of the steel cables bears the structure's self-weight, reducing the bending stress and deformation of the steel beam structure in the vertical plane. This achieves the requirement of continuous and reliable force transmission for the support structure system under large-span, column-free foundation pit support conditions without significantly increasing the cross-section of the support components. Furthermore, by setting up a prestressed servo structure for the supports, it limits soil deformation caused by foundation pit excavation to a smaller range, reducing the impact of underground space development on the surrounding environment.

[0047] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the support column may be, but is not limited to, an integrated driven steel pipe pile structure system, a driven steel pipe concrete pile structure system, a drilled cast-in-place pile with inserted steel pipe column structure system, a drilled cast-in-place pile with inserted lattice steel column structure system, a cement mixing pile with inserted steel pipe column structure system, a cement mixing pile with inserted lattice steel column structure system, or a cement mixing pile with inserted precast reinforced concrete column structure system, etc. The corresponding component cross-section is determined according to the design calculation of the concrete force transmission distribution conversion structure system.

[0048] In one embodiment of the concrete force distribution and conversion structural system of the present invention, the force distribution beam may be, but is not limited to, a cast-in-place reinforced concrete beam structural system, a cast-in-place steel-reinforced concrete composite beam structural system, a steel beam structural system, a lattice steel beam structural system, a precast reinforced concrete beam structural system, or a precast steel-reinforced concrete composite beam structural system, etc., and the corresponding component cross-section is determined according to the design calculation of the foundation pit support stress and the concrete force distribution and conversion structural system.

[0049] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the cast-in-place steel-reinforced concrete composite beam structure system transmits the force to the distribution beam, and the precast steel-reinforced concrete composite beam structure system transmits the force to the distribution beam. The steel frame of the cast-in-place steel-reinforced concrete composite beam structure system or the precast steel-reinforced concrete composite beam structure system can be adjusted according to the magnitude of the foundation pit support force. When the support force is small, a horizontal beam-type steel frame is used, and when the support force is large, a horizontal arch-type steel frame is used to reduce the cross-sectional size of the force-transmitting distribution beam.

[0050] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the concrete side support force transmission structure system is composed of horizontal, longitudinal, transverse and oblique reinforced concrete or steel-reinforced concrete composite structural beams, and a reinforced concrete slab is provided on the top of the concrete side support force transmission structure system.

[0051] Here, a planar beam system can be configured with different combinations of longitudinal, transverse, and oblique beams according to the different shapes and boundary lines of the foundation pit, forming a horizontal force transmission system for the foundation pit on both sides of the area that needs to be supported by the foundation pit; a reinforced concrete slab can be set on the top of the planar beam system to improve the in-plane stiffness of the planar beam system and serve as an operating platform for foundation pit construction.

[0052] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the central tensioned steel beam support structure system includes: a main beam and a tensioned structure, wherein the main beam adopts steel without vertical support, steel pipe, or lattice steel structure component; the tensioned structure is composed of steel cables and web members, the two ends of the steel cables are connected to the two ends of the main beam, one end of the web members is connected to the steel cables through cable clamp nodes, and the other end of the web members is connected to the main beam through preset nodes.

[0053] Here, the central tensioned steel beam support structure system constitutes the horizontal force transmission system for the foundation pit support in the area that needs to be crossed;

[0054] The design of the tensioned steel beam should be based on the required span of the area to be crossed and the different material strengths, and the cross-sectional dimensions of the main beam, steel cable, web members, the sag of the tensioned structure, and the pretension value of the cable should be determined according to the design calculation results.

[0055] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the steel cable is tensioned and released using an automatic tensioning anchor to adjust the tension of the steel cable according to different design conditions to meet the load requirements.

[0056] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the pre-embedded force transmission joint component includes: an anchor bar welded plate component or a steel conversion welded joint component.

[0057] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the anchor bar welded plate component is used when the force distribution beam is a reinforced concrete structure, the pre-embedded force transmission joint component is in the form of an anchor bar welded plate, the anchor bar is embedded in the force distribution beam, and the welded plate is placed on the surface of the component connecting the force distribution beam and the middle tensioned steel beam support structure system.

[0058] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the steel conversion welded joint is used when the force distribution beam adopts a steel-reinforced concrete beam structure, a steel beam structure or a lattice steel beam structure, and the pre-embedded force distribution joint component adopts the steel conversion welded joint form, which is welded to the steel skeleton in the force distribution beam or the connection side between the steel force distribution beam and the central tensioned steel beam support structure system.

[0059] In one embodiment of the foundation pit support device combining concrete and tensioned steel beams of the present invention, the steel support prestressed servo connection component is used to set a steel support prestressed servo connection component at one or both ends of the central tensioned steel beam support structure system when the foundation pit deformation control requirements are high. The steel support prestressed servo connection component is composed of a servo and a conversion connection component.

[0060] Here, the conversion connection component is designed based on the size and form of the server cross section and the size and form of the pre-embedded force transmission joint component cross section, ensuring that the straight line connecting the centroid of the server cross section and the centroid of the pre-embedded force transmission joint component cross section coincides with the designed horizontal force transmission path of the foundation pit support.

[0061] Specifically, Figure 1 This is a cross-sectional view of the construction of a large-span unsupported foundation pit support system for a concrete-tensioned steel beam composite structure according to an embodiment of the present invention. Figure 2 This is a plan view of a large-span unsupported foundation pit support system for a concrete-tensioned steel beam composite structure according to an embodiment of the present invention; it includes: tensioned beam support 11; concrete support 12; force distribution beam 13; support column 14; embedded welding plate 15; servo system 16; and conversion connection component 17.

[0062] Figure 3 This is a design drawing of a centrally tensioned steel beam support structure system according to an embodiment of the present invention; including: a steel main beam 21; steel cables 22; web members 23; cable clamps 24; pre-set nodes 25; stiffening plates 26; end automatic tensioning anchors 27; central automatic tensioning anchors 28; and connecting plates 29.

[0063] Figure 4 This is a design drawing of the automatic end tensioning anchor of the present invention; it includes: cable anchor plate 31; hydraulic chamber partition 32; piston 33; sensing piston 34; stress sensor 35; data transmission interface 36; oil nozzle 37; hydraulic chamber 38;

[0064] Figure 5 This is a design drawing of the automatic tensioning anchor at both ends of the present invention; it includes: steel cable 71; cable anchor plate 72; hydraulic chamber partition 73; oil nozzle 74; tensioning piston 75; tensioning piston end cable anchor plate 76; pressure sensor 77; and data transmission interface 78.

[0065] Figure 6This is a design drawing of the web bar clamp of the present invention; upper clamping plate 41; lower clamping plate 42; bolt 43; nut 44;

[0066] Figure 7 This is a design drawing of a concrete force distribution and conversion structure system according to an embodiment of the present invention; including: arched steel-concrete beam 51; arched steel 52; and studs 53;

[0067] Figure 8 This is a design drawing of a pre-embedded force transmission joint component according to an embodiment of the present invention; including: a pre-embedded connector 61; and a pre-embedded steel plate 62;

[0068] Figure 9 This is a design drawing of a steel support prestressed servo connection component according to an embodiment of the present invention.

[0069] In summary, this invention addresses the current situation where subway tunnels and municipal road tunnels are densely distributed in urban core areas, and urban underground space development will increasingly face situations where it crosses underground tunnel structures. The underground space foundation pit retaining and support structure system needs to avoid the underground tunnel structure and its protection range. The support system in the foundation pit needs to cross a span of 30m or more, making it impossible to install support columns. Existing reinforced concrete support and steel support systems are difficult to meet this requirement due to the limitations of component slenderness ratio and material strength. This invention provides a large-span unsupported foundation pit support system based on a concrete-tensioned steel beam composite structure. It combines a concrete support system with a steel support system, utilizing a specially designed concrete force distribution and conversion structure and pre-embedded force transmission joint components. It also provides conditions for setting up a prestressed servo structure for the support. By combining tension steel cables and chord-supported web members with the steel beam structure to form a self-balancing tensioned beam system, the tension of the steel cables bears the structure's self-weight, reducing the bending stress and deformation of the steel beam structure in the vertical plane. This achieves the requirement of continuous and reliable force transmission for the support structure system under large-span, column-free foundation pit support conditions. Furthermore, by setting up a prestressed servo structure for the support, the soil deformation caused by foundation pit excavation can be limited to a small range, reducing the impact of underground space development on the surrounding environment.

[0070] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0071] Obviously, those skilled in the art can make various modifications and variations to the invention without departing from the spirit and scope of the invention. Therefore, if these modifications and variations fall within the scope of the claims of the invention and their equivalents, the invention is also intended to include these modifications and variations.

Claims

1. A foundation pit support device combining concrete and tensioned steel beams, characterized in that, include: A concrete edge-supported force-transfer structure system is installed on both sides of the area to be crossed, extending to the vertical retaining edge of the foundation pit; The central tensioned steel beam support structure system is set above the area to be crossed and connects to the concrete side support force transmission structure system on both sides. The concrete force distribution and conversion structure system includes: a supporting column and a force distribution beam, wherein one end of the force distribution beam is connected to the concrete side support force transmission structure system, and the other end of the force distribution beam is connected to the central tensioned steel beam support structure system; the supporting column serves as a vertical support member for the force distribution beam, one end of the supporting column is connected to the force distribution beam, and the other end of the supporting column is inserted into the soil for support. A pre-embedded force transmission joint component is pre-embedded in the force transmission distribution beam and connected to the central tensioned steel beam support structure system; The steel support prestressed servo connection component is connected at one end to the central tensioned steel beam support structure system, and at the other end to the force distribution beam through the pre-embedded force transmission joint component. The supporting columns adopt an integrated driven steel pipe pile structure system, a driven steel pipe concrete pile structure system, a drilled cast-in-place pile internal steel pipe column structure system, a drilled cast-in-place pile internal lattice steel column structure system, a cement mixing pile internal steel pipe column structure system, a cement mixing pile internal lattice steel column structure system, or a cement mixing pile internal precast reinforced concrete column structure system. The force distribution beam adopts a cast-in-place reinforced concrete beam structure system, a cast-in-place steel-reinforced concrete composite beam structure system, a steel beam structure system, a lattice steel beam structure system, a precast reinforced concrete beam structure system, or a precast steel-reinforced concrete composite beam structure system.

2. The foundation pit support device combining concrete and tensioned steel beams as described in claim 1, characterized in that, The concrete edge support force transmission structure system is composed of horizontal, longitudinal, transverse and diagonal reinforced concrete or steel-reinforced concrete composite structural beams, and a reinforced concrete slab is provided on the top of the concrete edge support force transmission structure system.

3. The foundation pit support device combining concrete and tensioned steel beams as described in claim 1, characterized in that, The central tensioned steel beam support structure system includes: a main beam and a tensioned structure. The main beam is made of steel without vertical support, steel pipe, or lattice steel structure components. The tensioned structure consists of steel cables and web members. The two ends of the steel cables are connected to the two ends of the main beam. One end of the web members is connected to the steel cables through cable clamp nodes, and the other end of the web members is connected to the main beam through preset nodes.

4. The foundation pit support device combining concrete and tensioned steel beams as described in claim 3, characterized in that, The steel cable is tensioned and released using an automatic tensioning anchor to adjust the cable tension according to different design conditions to meet load requirements.

5. The foundation pit support device combining concrete and tensioned steel beams as described in claim 1, characterized in that, The pre-embedded force transmission joint components include: anchor bar welded plate components or steel conversion welded joint components.

6. The foundation pit support device combining concrete and tensioned steel beams as described in claim 5, characterized in that, The anchor bar welded plate component is used when the force distribution beam is a reinforced concrete structure, the pre-embedded force transmission joint component is in the form of an anchor bar welded plate, the anchor bar is embedded in the force distribution beam, and the welded plate is placed on the surface of the component connecting the force distribution beam and the middle tensioned steel beam support structure system. The aforementioned steel conversion welded joint type is used when the force distribution beam adopts a steel-reinforced concrete beam structure, a steel beam structure, or a lattice steel beam structure. The pre-embedded force transmission joint component adopts the steel conversion welded joint type, which is welded to the steel skeleton inside the force distribution beam or the connection side between the steel force distribution beam and the central tensioned steel beam support structure system.

7. The foundation pit support device combining concrete and tensioned steel beams as described in claim 1, characterized in that, The steel support prestressed servo connection component is used when the deformation control requirements of the foundation pit are high. The steel support prestressed servo connection component is installed at one or both ends of the central tensioned steel beam support structure system. The steel support prestressed servo connection component is composed of a servo and a conversion connection component.

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