Self-adaptive foundation pit steel support anti-seismic structure and using method

Abstract

The invention discloses a self-adaptive foundation pit steel support anti-seismic structure which comprises a set of foundation pit support structures, steel supports are arranged on the side faces of the foundation pit support structures, and steel support anti-seismic assemblies with self-adaptive deformation capacity are arranged between the steel supports of the adjacent foundation pit support structures. The steel support anti-seismic assembly is an anti-seismic elastic assembly with elastic deformation capacity. According to the self-adaptive foundation pit steel support anti-seismic structure and the using method, the design is reasonable, the steel support anti-seismic assembly with the self-adaptive deformation capacity is additionally arranged between the steel supports, the anti-seismic assembly can be automatically suitable for foundation pit deformation under the earthquake action, manual intervention is not needed, the self-adaptive deformation capacity is achieved, and the anti-seismic effect is good. The shock resistance is obviously improved while the conventional bearing performance is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of civil engineering foundation pit support, and in particular to an adaptive foundation pit steel support earthquake-resistant structure and a use method thereof. Background Art

[0002] The existing deep foundation pit steel support system mainly relies on rigid connections to achieve compressive bearing, and its structural solution has the following defects:

[0003] (1) The steel support is only in contact with the retaining structure and has no connection. It can only transmit pressure but not tension. As a result, the steel support can only withstand axial pressure and cannot adapt to the horizontal tensile stress generated by earthquakes. Under the action of earthquakes, the steel support is prone to fall off, which in turn causes the foundation pit to collapse.

[0004] (2) The existing support system allows for limited deformation. According to Table 8.0.4 of the Technical Standard for Monitoring Construction Foundation Pit Engineering (GB50497-2019), the absolute value of the horizontal displacement of a first-level foundation pit using cast-in-place piles and ground-connected walls as retaining structures is 20-30 mm. Zhu Suyu, in his paper "Seismic Performance Test of Pile Support Structures in Deep Foundation Pit of Super-High-Rise Buildings" (Journal of South China Earthquake, December 2019), stated that the maximum horizontal displacement of the foundation pit retaining structure is 25 cm. Such a large displacement obviously exceeds the adaptability of the steel support.

[0005] (3) Although the duration of an earthquake is relatively short, the entire foundation pit is displaced back and forth under the action of an earthquake, so the displacement compensation device is required to have adaptive capabilities; if the adaptive capabilities are weak, the deep foundation pit steel support cannot meet the large deformation under the action of an earthquake, resulting in the overall instability of the support system.

[0006] For example, patent CN219840089U discloses a foundation pit support structure with an anti-seismic transmission function, which includes a main structure, an anti-seismic transmission mechanism, and an auxiliary support mechanism. The anti-seismic transmission mechanism is distributed at both ends of the main structure, and an auxiliary support mechanism is provided on one side of the anti-seismic transmission mechanism. The anti-seismic transmission mechanism includes pile foundations, pile reinforcement, connecting reinforcement frames, connecting piles, crossbeams, and connecting beams, and pile foundations are provided with pile reinforcements inside. When a sense of vibration occurs, both ends of the overall foundation pit enhance the stability of the surroundings through the deepened pre-buried structure of the connecting piles and the inner piles at the bottom, and the sense of vibration that occurs will be transmitted by the inclined connecting beams, and the sense of vibration will be transmitted to the connecting reinforcement frames and pile foundation positions through the connecting beams, thereby reducing the impact of the vibration through the deepened structure of the pile foundation. Its structure is a reinforced concrete structure, and its displacement compensation adaptive ability is relatively weak. Summary of the Invention

[0007] In view of the shortcomings of the existing technology, the present invention provides an adaptive foundation pit steel support seismic resistant structure and a method of use, which has adaptive deformation capability, ensuring conventional bearing performance while significantly improving seismic resistance.

[0008] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0009] An adaptive foundation pit steel support seismic resistant structure includes a group of foundation pit retaining structures. Steel supports are provided on the sides of the foundation pit retaining structures. Steel support seismic resistant components with adaptive deformation capability are provided between the steel supports of adjacent foundation pit retaining structures.

[0010] The steel support anti-seismic component is an anti-seismic elastic component with elastic deformation capability.

[0011] The steel supports are connected to the sides of the foundation pit retaining structure through corresponding steel waist beams.

[0012] The steel support and the steel waist beam are connected via a detachable structure.

[0013] The detachable structure is a steel supporting movable head.

[0014] The anti-seismic elastic component includes a spring unit and a pair of flange structures; the spring unit is pre-loaded and arranged between the pair of flange structures, and the outer sides of the flange structures are connected to corresponding steel supports.

[0015] A sleeve is provided on the inner side of the flange structure. Two sleeves of a pair of flange structures are inserted and movably matched, and the spring unit is located in the sleeve.

[0016] A steel rod is arranged in one of the sleeves, and the spring unit is sleeved on the corresponding steel rod. A partition is arranged in the other sleeve, and an opening is arranged on the partition for the steel rod to pass through.

[0017] It also includes a locking screw for spring pre-compression positioning, and a flange hole is provided on the flange structure corresponding to the end of the locking bolt.

[0018] A method for using the adaptive foundation pit steel support seismic resistant structure comprises the following steps:

[0019] Step 1: Determine the number of spring units to be installed, n = F / KL; where F is the design axial force of the steel support under normal use, K is the stiffness coefficient of the spring unit, and L is the compression of the spring unit;

[0020] Step 2: Complete pre-compression of the spring unit on the ground, with the compression force equal to the design value of the steel support axial force, and lock it with a screw;

[0021] Step 3: Connect the seismic components and steel supports with flanges;

[0022] Step 4: Install steel supports;

[0023] Step 5: After the steel support is installed, remove the locking screws of the seismic assembly.

[0024] Compared with the prior art, the present invention has the following advantages:

[0025] The adaptive foundation pit steel support seismic resistance structure and usage method are reasonably designed. Steel support seismic resistance components with adaptive deformation capabilities are added between the steel supports. The seismic resistance components can automatically adapt to the foundation pit deformation caused by earthquakes without the need for human intervention. It has adaptive deformation capabilities, ensuring conventional bearing performance while significantly improving seismic resistance. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] The following is a brief description of the contents and symbols in the drawings of this specification:

[0027] Figure 1 This is an overall diagram of the use stages of the present invention.

[0028] Figure 2 Exploded view of the seismic resistant assembly of the present invention.

[0029] Figure 3 This is a comparison diagram of the seismic resistant assembly of the present invention before and after pre-compression.

[0030] In the picture:

[0031] 1- foundation pit retaining structure, 2- steel waist beam, 3- steel support movable head, 4- steel support, 5- seismic component, 6- locking screw, 7- spring unit, 8- casing structure, 8-1- casing I, 8-2- casing II, 9- flange structure, 9-1- flange I, 9-2- flange II, 10- partition, 11- steel rod. DETAILED DESCRIPTION

[0032] The specific implementation of the present invention will be further explained in detail below through description of embodiments with reference to the accompanying drawings.

[0033] like Figures 1 to 3 As shown, the adaptive foundation pit steel support seismic resistant structure includes a group of foundation pit retaining structures, steel supports 4 are provided on the sides of the foundation pit retaining structure 1, and steel support seismic resistant components 5 with adaptive deformation capability are provided between the steel supports of adjacent foundation pit retaining structures; the steel support seismic resistant components are seismic resistant elastic components with elastic deformation capability.

[0034] The steel supports are connected to the sides of the foundation pit retaining structure via corresponding steel waist beams 2. The steel supports and the steel waist beams are connected by a removable structure. Preferably, the removable structure is a steel support joint 3. Bolt fasteners can also be used to connect the removable structure. This removable connection facilitates the installation of the steel support seismic components.

[0035] The anti-seismic elastic assembly includes a spring unit 7 and a pair of flange structures 9. The spring unit is preloaded and positioned between the flange structures, the outer sides of which are connected to corresponding steel supports. It also includes a locking screw for preloading the spring, and flange holes are provided on the flange structures corresponding to the ends of the locking screws.

[0036] A sleeve structure 8 is installed inside the flange structure. A pair of sleeves in the flange structure are inserted and flexibly engaged, with the spring unit located within the sleeves. One sleeve contains a steel rod 11, which the spring unit fits over. The other sleeve contains a partition 10 with a hole for the steel rod to pass through. The structure is compact, stable, and reliable.

[0037] The adaptive foundation pit steel support seismic resistant structure and the use method of the present invention are reasonably designed. Steel support seismic resistant components with adaptive deformation capabilities are added between the steel supports. The seismic resistant components can automatically adapt to the foundation pit deformation caused by earthquakes without the need for manual intervention. It has adaptive deformation capabilities, ensuring conventional bearing performance while significantly improving seismic resistance.

[0038] The core component of this invention is the spring unit of the seismic elastic assembly, made of high-strength low-alloy steel, with a free length of approximately 1.5 times the pre-compression amount. The number of spring units is determined by the design axial force of the steel support and the pre-compression deformation required.

[0039] The key process involves compressing the spring unit before installing the seismic component, and determining the compression amount and force. The compression amount is equal to the outward deformation of the foundation pit retaining structure at the corresponding support location under earthquake action, plus a certain margin to ensure that the support deformation can adapt to the deformation requirements of the earthquake and prevent the support from being crushed or falling off. The pre-compression force is the design value of the axial force of the steel support. This allows the seismic component to deform in advance, preventing excessive deformation of the foundation pit during normal use.

[0040] After the seismic assembly is compressed, it is locked using locking screws 6. The entire seismic assembly is installed on the steel support. Once the steel support is complete, the locking screws are removed and installed, completing the installation of the seismic assembly. Under the action of an earthquake, the spring unit compresses and rebounds to accommodate deformation of the foundation pit.

[0041] The preferred structure of the seismic elastic component is:

[0042] Seismic elastic components include:

[0043] The spring unit 7 is made of high-strength low-alloy steel, with a free length of 1.5 times the compression amount. The number of spring units is determined by calculation according to needs.

[0044] The steel rod 11 serves as a guide and is made of high-strength low-alloy steel. Its length is greater than the free length of the spring unit 7. One end of the steel rod 11 is welded to the flange II 9-2 and the other end passes through the partition 10.

[0045] The spring unit 7 is sleeved on the outside of the steel rod 11;

[0046] The partition 10 is welded to the sleeve I 8-1 and a hole is opened at the corresponding position of the steel rod 11 to ensure that the steel rod 11 can pass through the partition;

[0047] The sleeve I8-1 is welded to the flange 9-1I, and the sleeve II8-2 is welded to the flange II9-2. The inner diameter of the sleeve I8-1 is slightly larger than the outer diameter of the sleeve II8-2, and the gap between them can be filled with grease or the like for lubrication.

[0048] The locking screw 6 connects flange Ⅰ 9-1 and flange 9-2Ⅱ.

[0049] The anti-seismic assembly is connected to the steel support 4 through a flange.

[0050] The method for using the adaptive foundation pit steel support earthquake-resistant structure of the present invention comprises the following steps:

[0051] Step 1: Determine the number of spring units to be installed, n = F / KL; where F is the design axial force of the steel support under normal use, K is the stiffness coefficient of the spring unit, and L is the compression of the spring unit;

[0052] Step 2: Complete pre-compression of the spring unit on the ground, with the compression force equal to the design value of the steel support axial force, and lock it with a screw;

[0053] Step 3: Connect the seismic components and steel supports with flanges;

[0054] Step 4: Install steel supports;

[0055] Step 5: After the steel support is installed, remove the locking screws of the seismic assembly.

[0056] The present invention has the following advantages:

[0057] Improved seismic performance: The compression and rebound of the spring unit meet the deformation of the foundation pit under the action of the earthquake, preventing the steel support from being damaged or falling off, and ensuring the safety of the foundation pit under earthquake conditions;

[0058] Self-adaptation: By setting the preload of the spring unit, the seismic assemblies can automatically adapt to the deformation of the foundation pit caused by the earthquake without the need for manual intervention;

[0059] Does not affect the normal use of the foundation pit: the preload of the seismic component is the design value of the steel support axial force, so that the seismic resistance will not produce additional deformation during the normal use of the foundation pit, which will cause the foundation pit to deform beyond the limit.

[0060] The above is only an illustration of a preferred embodiment of the present invention. The above technical features can be arbitrarily combined to form multiple embodiments of the present invention.

[0061] The present invention is described above by way of example in conjunction with the accompanying drawings. It is obvious that the specific implementation of the present invention is not limited to the above-mentioned method. As long as various non-substantial improvements are made using the concept and technical solution of the present invention, or the concept and technical solution of the present invention are directly applied to other occasions without improvement, they are all within the scope of protection of the present invention.

Claims

1. An adaptive foundation pit steel support seismic structure, comprising a set of foundation pit retaining structures, with steel supports provided on the sides of the foundation pit retaining structures, characterized in that: Steel support anti-seismic components with adaptive deformation capability are provided between the steel supports of adjacent foundation pit retaining structures.

2. The adaptive foundation pit steel support seismic structure according to claim 1, characterized in that: The steel support anti-seismic component is an anti-seismic elastic component with elastic deformation capability.

3. The adaptive foundation pit steel support seismic structure according to claim 1, characterized in that: The steel supports are connected to the sides of the foundation pit retaining structure through corresponding steel waist beams.

4. The adaptive foundation pit steel support seismic structure according to claim 3, characterized in that: The steel support and the steel waist beam are connected via a detachable structure.

5. The adaptive foundation pit steel support seismic structure according to claim 4, characterized in that: The detachable structure is a steel supporting movable head.

6. The adaptive foundation pit steel support seismic structure according to claim 2, characterized in that: The anti-seismic elastic component includes a spring unit and a pair of flange structures; the spring unit is pre-loaded and arranged between the pair of flange structures, and the outer sides of the flange structures are connected to corresponding steel supports.

7. The adaptive foundation pit steel support seismic structure according to claim 6, characterized in that: A sleeve is provided on the inner side of the flange structure. Two sleeves of a pair of flange structures are inserted and movably matched, and the spring unit is located in the sleeve.

8. The adaptive foundation pit steel support seismic structure according to claim 7, characterized in that: A steel rod is arranged in one of the sleeves, and the spring unit is sleeved on the corresponding steel rod. A partition is arranged in the other sleeve, and an opening is arranged on the partition for the steel rod to pass through.

9. The adaptive foundation pit steel support seismic structure according to claim 6, characterized in that: It also includes a locking screw for spring pre-compression positioning, and a flange hole is provided on the flange structure corresponding to the end of the locking bolt.

10. A method for using the adaptive foundation pit steel support seismic structure according to any one of claims 1 to 9, characterized in that: The following steps are involved: Step 1: Determine the number of spring units to be installed, n = F / KL; where F is the design axial force of the steel support under normal use, K is the stiffness coefficient of the spring unit, and L is the compression of the spring unit; Step 2: Complete pre-compression of the spring unit on the ground, with the compression force equal to the design value of the steel support axial force, and lock it with a screw; Step 3: Connect the seismic components to the steel support with flanges; Step 4: Install steel supports; Step 5: After the steel support is installed, remove the locking screws of the seismic assembly.

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