Foundation pit external corner three-way steel truss and concrete base combined supporting structure

Abstract

The invention relates to the technical field of foundation pit supporting engineering, and discloses a foundation pit external corner three-way steel truss and concrete base combined supporting structure which comprises a foundation pit external corner located in a foundation pit and steel truss supports located in the foundation pit in three directions, and an integrally-formed concrete base is poured at the position of the foundation pit external corner. The steel truss supports in the three directions are connected with the external corners of the foundation pit through concrete bases. The steel truss supports in the three directions are mutually connected and fixed at positions far away from the concrete base through beam string structures to form a space beam string structure system; through the combination of the three-way steel truss and the integrated concrete base, the problem of stress concentration at the external corner of the foundation pit is solved, a space beam string structure system is formed, and the overall lateral displacement resistance and stability are remarkably improved; the steel supports and the concrete supporting beams are arranged in different directions, uniform load transmission is achieved, and the local deformation risk is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of foundation pit support engineering, in particular to a foundation pit external corner three-way steel truss and concrete base combined support structure. BACKGROUND

[0002] At present, the beam string steel truss support structure is widely used in the field of foundation pit support engineering. For the position of the foundation pit external corner, due to the existence of stress concentration, in order to effectively control the stress and deformation of the position of the foundation pit external corner, steel supports need to be set in three directions.

[0003] The single pure steel support has the disadvantages of plane intersection, complex stress, poor stability, and inconvenient construction at the position of the foundation pit external corner. SUMMARY

[0004] The present application aims to provide a foundation pit external corner three-way steel truss and concrete base combined support structure, which aims to solve the problems of poor stability of single pure steel support, plane intersection of multi-directional steel support at the position of the foundation pit external corner, complex steel structure node, and difficult construction in the prior art.

[0005] The present application is a foundation pit external corner three-way steel truss and concrete base combined support structure, which comprises a foundation pit external corner located in a foundation pit and steel truss supports in three directions located in the foundation pit. An integrated concrete base is poured at the position of the foundation pit external corner. The steel truss supports in three directions are connected to the foundation pit external corner through the concrete base. The steel truss supports in three directions are connected and fixed to each other through a beam string structure at a position away from the concrete base, forming a spatial beam string structure system. The steel truss supports in three directions are a direction one steel support, a direction two steel support, and a direction three steel support, respectively. The direction one steel support, the direction two steel support, and the direction three steel support are arranged in three directions of the foundation pit external corner, and each direction steel support is combined with the concrete base. The concrete base comprises concrete support beams extending in three different directions. The concrete support beams extending in three different directions are a direction one concrete support beam, a direction two concrete support beam, and a direction three concrete support beam, respectively. The direction one concrete support beam, the direction two concrete support beam, and the direction three concrete support beam are arranged on two external corner walls of the foundation pit external corner. The direction one steel support is connected to the direction one concrete support beam. The direction two steel support is connected to the direction two concrete support beam. The direction three steel support is connected to the direction three concrete support beam.

[0006] Furthermore, embedded connectors for connecting steel truss supports are embedded at the ends of the three concrete support beams, and one end of each steel truss support is fixedly connected to the end of the corresponding concrete support beam through the embedded connector; the lower part of the embedded connector is connected to the concrete base, and the upper part of the embedded connector is exposed outside the concrete base.

[0007] Furthermore, an outer pit inner corner located outside the foundation pit is formed at the outer pit inner corner, and a concrete outer base is cast on the outer pit inner corner. The concrete outer base is arranged opposite to the concrete base.

[0008] Furthermore, the concrete outer base includes a back-tension beam and a back-tension plate. The two inner corner walls of the outer inner corner of the pit are connected by multiple back-tension beams. The multiple back-tension beams are arranged in sequence from the inside to the outside of the outer inner corner of the pit, and the lengths of the multiple back-tension beams increase in sequence. Adjacent back-tension beams are connected by back-tension plates, and the multiple back-tension beams are connected by connecting beams.

[0009] Furthermore, the concrete base also includes a concrete slab connecting the three concrete support beams, and a stiffening structure arranged inside or on the surface of the concrete base for enhancing its overall rigidity and stability.

[0010] Furthermore, the reinforcing structure includes one or more of stiffening ribs, shear keys or rib plates arranged between concrete support beams, at the junction of beams and slabs or on the slab surface.

[0011] Furthermore, the formation of the spatial beam string structure system includes connecting and fixing the end nodes of the three steel trusses through node plates, connecting plates and connecting bolts or pins.

[0012] Furthermore, it also includes tensioning prestressed cables between or inside the connected and fixed steel truss supports to form a complete tensioned beam structure.

[0013] Furthermore, a steel cage is provided in the concrete support beam, the steel cage is welded to the steel mesh in the concrete base, the steel cage is welded to the bottom of the embedded connector, the steel cage is connected to the steel truss support through the embedded connector to form a rigid whole, and the steel truss support and the embedded connector are connected by welding or high-strength bolts; A steel plate is embedded in the outer end surface of the concrete support beam, and the steel plate is connected to the steel truss support by welding or high-strength bolts.

[0014] Further, a plurality of counter-pulling structures are arranged in the foundation pit external corner, the counter-pulling structure comprises a counter-pulling column, the counter-pulling column transversely penetrates the foundation pit external corner, and two ends of the counter-pulling column are arranged in the concrete outer base and the concrete base respectively, a plurality of outer struts are welded on the counter-pulling column, the plurality of outer struts are arranged along the axial direction of the counter-pulling column and are spaced around the counter-pulling column, part of the outer struts arranged in the concrete outer base are welded and connected with the steel bars in the back-pulling beam, and part of the outer struts arranged in the concrete base are welded and connected with the steel bar mesh or the steel bar beam cage. Two ends of the counter-pulling column are welded with steel plate structures respectively, and the two steel plate structures are arranged in the concrete outer base and the concrete base respectively, and the steel plate structure is formed by two steel sheets being cross-welded in a cross shape.

[0015] Compared with the prior art, the foundation pit external corner three-direction steel truss and concrete base combined support structure provided by the application solves the stress concentration problem at the foundation pit external corner through the combination of the three-direction steel truss and the integrated concrete base, forms a space cable-stayed beam system, and significantly improves the overall lateral displacement resistance and stability; the steel support and the concrete support beam are arranged in different directions to realize uniform load transmission and reduce the risk of local deformation; and the problems of poor stability of single pure steel support, planar intersection of multi-direction steel support at the foundation pit external corner position, complex steel structure node and difficult construction are solved. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a top view structural schematic diagram of the foundation pit external corner three-direction steel truss and concrete base combined support structure provided by the application; Figure 2 is a top view structural schematic diagram of the connection of the foundation pit external corner with the concrete base and the steel truss support provided by the application; Figure 3 is a local cutaway structural schematic diagram of the concrete base provided by the application; Figure 4 is a side view structural schematic diagram of the counter-pulling column provided by the application.

[0017] In the figure: foundation pit external corner 10, steel truss support 20, concrete base 30, cable-stayed beam structure 40, pre-buried connecting piece 50, tensioned prestressed cable 60, counter-pulling structure 70, concrete outer base 11, back-pulling beam 111, back-pulling plate 112, connecting beam 113, direction one steel support 21, direction two steel support 22, direction three steel support 23, direction one concrete support beam 31, direction two concrete support beam 32, direction three concrete support beam 33, concrete plate 34, stiffening structure 35, steel bar beam cage 36, steel bar mesh 37, enclosing frame 38, shock isolation cushion layer 381, shock absorption plate 382, counter-pulling column 71, outer strut 72, steel plate structure 73. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0019] The implementation of the present invention is described in detail below with reference to specific embodiments.

[0020] The same or similar numbers in the drawings of this embodiment correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "up", "down", "left", "right", etc. indicate directions or positional relationships, they are based on the directions or positional relationships shown in the drawings. This is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, the terms describing the positional relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0021] Reference Figure 1-4 The figure shows a preferred embodiment of the present invention.

[0022] The combined support structure of the three-way steel truss and concrete base 30 at the external corner of the foundation pit 10 includes the external corner of the foundation pit 10 located within the foundation pit and steel truss supports 20 located in three directions within the foundation pit. An integrally formed concrete base 30 is cast at the location of the external corner of the foundation pit 10. The steel truss supports 20 in the three directions are connected to the external corner of the foundation pit 10 through the concrete base 30. The steel truss supports 20 in the three directions are interconnected and fixed to each other at a position away from the concrete base 30 through a beam string structure 40, forming a spatial beam string structure 40 system. The steel truss supports 20 in the three directions are respectively a steel support 21 in direction 1, a steel support 22 in direction 2, and a steel support 23 in direction 3. The steel support 21 in direction 1, the steel support 22 in direction 2, and the steel support 23 in direction 3 are respectively arranged in three directions of the external corner of the foundation pit 10, and the steel supports in each direction are combined with the concrete base 30. The concrete base 30 includes concrete support beams extending in three different directions, which are concrete support beam 31 in direction one, concrete support beam 32 in direction two, and concrete support beam 33 in direction three. Concrete support beam 31 in direction one, concrete support beam 32 in direction two, and concrete support beam 33 in direction three are respectively arranged on the two positive corner walls of the foundation pit positive corner 10. Steel support 21 in direction one is connected to concrete support beam 31 in direction one, steel support 22 in direction two is connected to concrete support beam 32 in direction two, and steel support 23 in direction three is connected to concrete support beam 33 in direction three.

[0023] The three-way steel truss and the concrete base 30 of the foundation corner 10 provided by the application are combined to solve the stress concentration problem of the foundation corner 10, form a space cable-stayed beam system, and significantly improve the overall lateral displacement resistance and stability; the steel support and the concrete support beam are arranged in different directions to realize uniform load transfer and reduce the risk of local deformation; and the problems of poor stability of a single pure steel support, planar intersection of multi-directional steel supports at the foundation corner position, complex steel structure nodes, and difficult construction are solved.

[0024] In the embodiment, a pre-buried connecting piece 50 for connecting the steel truss support 20 is pre-buried at the end of each of the three concrete support beams, one end of each steel truss support 20 is fixedly connected to the end of the corresponding concrete support beam through the pre-buried connecting piece 50, the lower part of the pre-buried connecting piece 50 is connected to the concrete base 30, and the upper part of the pre-buried connecting piece 50 is exposed outside the concrete base 30.

[0025] The pre-buried connecting piece 50 realizes the rigid connection of the steel truss and the concrete base 30 and enhances the node reliability; the lower part of the pre-buried connecting piece 50 is embedded in the concrete, and the upper part is exposed, which facilitates the rapid installation of the steel support later.

[0026] In the embodiment, a pit outer corner is formed at the position of the foundation corner 10, a concrete outer base 11 is poured on the pit outer corner, and the concrete outer base 11 and the concrete base 30 are arranged away from each other.

[0027] Balancing earth pressure: the inner and outer bases form a tension system to offset the asymmetric earth pressure in the foundation corner 10 area.

[0028] Inhibiting lateral displacement: the horizontal load is transmitted to the stable soil outside the pit through the external counterforce structure.

[0029] In the embodiment, the concrete outer base 11 includes back-pulling beams 111 and back-pulling plates 112, the two corner walls of the pit outer corner are connected through a plurality of back-pulling beams 111, the plurality of back-pulling beams 111 are arranged in sequence and at intervals along the inside-outside direction of the pit outer corner, the lengths of the plurality of back-pulling beams 111 increase in sequence, the adjacent back-pulling beams 111 are connected through the back-pulling plates 112, and the plurality of back-pulling beams 111 are connected through connecting beams 113.

[0030] Space truss effect: the multiple back-pulling structures form a three-dimensional stable frame to disperse external loads.

[0031] Progressive stress transfer: the stepped beam body realizes smooth transition of stress from inside to outside to avoid stress mutation.

[0032] In this embodiment, the concrete foundation 30 further includes a concrete slab 34 connecting three concrete support beams, and a stiffening structure 35 disposed within or on the surface of the concrete foundation 30 for enhancing its overall rigidity and stability.

[0033] The concrete slab 34 strengthens the synergistic effect of the three-way support beams, and the stiffening structure 35 (such as ribs and shear keys) significantly improves the local shear stiffness of the base.

[0034] In this embodiment, the stiffening structure 35 includes one or more stiffening ribs, shear keys or rib plates arranged between concrete support beams, at the junction of beams and slabs or on the slab surface.

[0035] Targetedly strengthen the weak locations at the junction of beams and slabs to avoid concrete cracking.

[0036] In this embodiment, the formation of the spatial beam string structure 40 system includes connecting and fixing the end nodes of the three steel truss supports 20 through node plates, connecting plates and connecting bolts or pins.

[0037] Node reliability: Mechanical connection ensures the stiffness and strength of the truss node and avoids welding deformation affecting the accuracy.

[0038] Quick assembly: Bolt / pin connection facilitates on-site adjustment and improves construction efficiency.

[0039] In this embodiment, prestressed cables 60 are further included between or within the connected and fixed steel truss supports 20 to form a complete beam string structure 40; the steel supports in various directions on the same wall surface in the foundation pit are connected by the beam string structure 40.

[0040] Active deformation control: Prestressed cables provide anti-camber stiffness to offset the deflection caused by earth pressure.

[0041] Lightweight design: The beam string structure uses 40% less steel.

[0042] In this embodiment, a steel cage 36 is provided in the concrete support beam. The steel cage 36 is welded to the steel mesh 37 in the concrete base 30. The steel cage 36 is welded to the bottom of the embedded connector 50. The steel cage 36 is connected to the steel truss support 20 through the embedded connector 50 to form a rigid whole. The steel truss support 20 and the embedded connector 50 are connected by welding or high-strength bolts. A steel plate is embedded in the outer end surface of the concrete support beam, and the steel plate is connected to the steel truss support 20 by welding or high-strength bolts.

[0043] The steel base plate can be a pre-buried steel plate, a pre-buried bolt sleeve or a steel end plate with anchor bars.

[0044] Optimization of rigid-flexible interface: The steel pad provides a uniform pressure-bearing surface, eliminating stress concentration at the concrete-steel structure interface.

[0045] Integrated structure: 36 welding of steel beam cage enables the joint work of concrete and steel structure, improving the fatigue resistance of the node.

[0046] In this embodiment, a plurality of tensioning structures 70 are provided in the foundation pit outer corner 10. The tensioning structures 70 include tensioning columns 71. The tensioning columns 71 transversely penetrate the foundation pit outer corner 10, and the two ends of the tensioning columns 71 are respectively provided in the concrete outer base 11 and the concrete base 30. A plurality of external support rods 72 are welded to the tensioning columns 71. The plurality of external support rods 72 are arranged at intervals along the axial direction of the tensioning columns 71. Some of the external support rods 72 located in the concrete outer base 11 are welded to the steel bars in the back tension beam 111, and some of the external support rods 72 located in the concrete base 30 are welded to the steel mesh 37 or the steel beam cage 36. Steel plate structures 73 are welded to both ends of the tension column 71. The two steel plate structures 73 are located in the concrete outer base 11 and the concrete base 30 respectively. The steel plate structures 73 are formed by cross-welding two steel sheets.

[0047] Active constraint mechanism: provides axial preload force to the tension column 71 to control the opening displacement of the positive corner 10 of the foundation pit.

[0048] Three-dimensional anchoring system: radial support rods + cross steel plates significantly enhance the anchoring force in concrete (increased by 300%+).

[0049] In this embodiment, an enclosure frame 38 is provided on the concrete base 30. The enclosure frame 38 is arranged around the circumference of the connection position between the steel truss support 20 and the concrete support beam to form an internal cavity running through from top to bottom. A seismic isolation pad 381 is provided in the internal cavity. The seismic isolation pad 381 is arranged around the circumference of the inner wall of the internal cavity. A plurality of shock-absorbing plates 382 extend outward from the bottom of the enclosure frame 38. The shock-absorbing plates 382 are arranged perpendicular to the bottom of the enclosure frame 38. The plurality of shock-absorbing plates 382 are arranged around the circumference of the enclosure frame 38. The shock-absorbing plates 382 are connected to the concrete base 30 by connecting bolts. The enclosing frame 38 is provided with a displacement monitoring system, which includes an inclination sensor and an optical fiber strain gauge, and the data is uploaded to the cloud platform every 10 minutes.

[0050] Dynamic response control: The seismic isolation pad 381 absorbs construction vibration energy and reduces the dynamic response of the structure.

[0051] Intelligent early warning: Inclination sensor + optical fiber strain gauge monitors node deformation in real time, achieving millimeter-level deformation early warning.

[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. The combined support structure of the three-way steel truss and concrete base at the outer corner of the foundation pit is characterized by: It includes a foundation pit positive corner located in the foundation pit and steel truss supports located in three directions in the foundation pit, an integrally formed concrete base is cast at the location of the foundation pit positive corner, and the steel truss supports in the three directions are connected to the foundation pit positive corner through the concrete base; the steel truss supports in the three directions are mutually connected and fixed by a beam string structure at a position away from the concrete base, forming a spatial beam string structure system; the steel truss supports in the three directions are respectively a direction one steel support, a direction two steel support, and a direction three steel support, and the direction one steel support, the direction two steel support, and the direction three steel support are respectively arranged in three directions of the foundation pit positive corner, and the steel supports in each direction are combined with the concrete base; The concrete base includes concrete support beams extending in three different directions, and the concrete support beams extending in three different directions are concrete support beam in direction one, concrete support beam in direction two, and concrete support beam in direction three. The concrete support beam in direction one, concrete support beam in direction two, and concrete support beam in direction three are respectively arranged on the two positive corner walls of the positive corner of the foundation pit. The steel support in direction one is connected to the concrete support beam in direction one, the steel support in direction two is connected to the concrete support beam in direction two, and the steel support in direction three is connected to the concrete support beam in direction three.

2. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 1, characterized in that: Embedded connectors for connecting steel truss supports are embedded at the ends of the three concrete support beams, and one end of each steel truss support is fixedly connected to the end of the corresponding concrete support beam through the embedded connector; the lower part of the embedded connector is connected to the concrete base, and the upper part of the embedded connector is exposed outside the concrete base.

3. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 2, characterized in that: An outer pit inner corner located outside the foundation pit is formed at the outer pit inner corner, and a concrete outer base is cast on the outer pit inner corner. The concrete outer base is arranged opposite to the concrete base.

4. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 3, characterized in that: The concrete outer base includes a back-tension beam and a back-tension plate. The two inner corner walls of the outer inner corner of the pit are connected by multiple back-tension beams. The multiple back-tension beams are arranged in sequence from the inside to the outside of the outer inner corner of the pit, and the lengths of the multiple back-tension beams increase in sequence. Adjacent back-tension beams are connected by back-tension plates, and the multiple back-tension beams are connected by connecting beams.

5. The foundation pit external corner three-way steel truss and concrete base combined support structure according to any one of claims 1 to 4, characterized in that: The concrete foundation further includes a concrete slab connecting the three concrete support beams, and a reinforcing structure arranged inside or on the surface of the concrete foundation for enhancing its overall rigidity and stability.

6. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 5, characterized in that: The reinforcing structure includes one or more of stiffening ribs, shear keys or rib plates arranged between concrete support beams, at the junction of beams and slabs or on the slab surface.

7. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 6, characterized in that: The formation of the spatial beam string structure system includes connecting and fixing the end nodes of the three steel trusses through node plates, connecting plates and connecting bolts or pins.

8. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 7, characterized in that: It also includes tensioning prestressed cables between or inside the connected and fixed steel truss supports to form a complete tensioned beam structure.

9. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 4, characterized in that: A steel cage is provided in the concrete support beam, the steel cage is welded to the steel mesh in the concrete base, the steel cage is welded to the bottom of the embedded connector, the steel cage is connected to the steel truss support via the embedded connector to form a rigid whole, and the steel truss support and the embedded connector are connected by welding or high-strength bolts; A steel plate is embedded in the outer end surface of the concrete support beam, and the steel plate is connected to the steel truss support by welding or high-strength bolts.

10. The foundation pit external corner three-way steel truss and concrete base combined support structure according to claim 9, characterized in that: A plurality of tensioning structures are provided in the positive corner of the foundation pit, and the tensioning structures include tensioning columns, the tensioning columns transversely pass through the positive corner of the foundation pit, and the two ends of the tensioning columns are respectively provided in the concrete outer base and the concrete base, a plurality of external support rods are welded to the tensioning columns, and the plurality of external support rods are arranged at intervals along the axial direction of the tensioning columns, some of the external support rods located in the concrete outer base are welded to the steel bars in the back tension beam, and some of the external support rods located in the concrete base are welded to the steel mesh or the steel beam cage; Steel plate structures are welded to both ends of the tension column. The two steel plate structures are located in the concrete outer base and the concrete base respectively. The steel plate structures are formed by cross-welding two steel sheets.

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