A mud-wall cast-in-place pile foundation pit support structure

Abstract

This utility model belongs to the technical field of foundation pit support engineering, and particularly relates to a mud-wall cast-in-place pile foundation pit support structure, including cast-in-place piles, which are formed by pile reinforcement and concrete pouring. The pile reinforcement includes longitudinally uniformly distributed continuous main bars, spiral stirrups spirally wound around the outside of the continuous main bars, reinforcing stirrups welded at intervals to the outside of the continuous main bars, supporting bars welded to the inside of the reinforcing stirrups, and a slot welded to the continuous main bars near the side of the foundation pit to be excavated; detachable short nails, detachably connected to the slots, including an attachment steel plate, a short nail head fixed to the attachment steel plate, and a short nail multi-directional hook detachably connected to the short nail head; a connection system, including buckles matched and connected to the slots and connecting reinforcement for connecting adjacent cast-in-place piles; and a drainage ditch, attached to the connecting reinforcement, including a water tank, through which surface water and seepage water inside and outside the foundation pit are intercepted and discharged. The above support structure does not require secondary drilling.

Description

Technical Field

[0001] This utility model belongs to the field of foundation pit support engineering technology, specifically relating to a mud slurry wall cast-in-place pile foundation pit support structure, which is particularly suitable for deep foundation pit support engineering in silty soil, silty clay and fine sand composite strata. Background Technology

[0002] With the development of cities in my country, the development and utilization of underground space is increasing, leading to a rise in foundation pit projects. As the excavation depth of foundation pit projects continues to increase, it brings great challenges to design and construction. Existing foundation pit support methods often have significant problems, including high environmental requirements, slow construction speed, high cost, easy deformation, and water leakage. These problems slow down project construction progress and even pose certain safety hazards.

[0003] Foundation pit support refers to the measures taken to protect the safety of the surrounding environment of the foundation pit during the construction of the underground main structure. It includes temporary support, reinforcement, protection, and groundwater control measures for the foundation pit. The structure that supports or reinforces the sidewalls of the foundation pit is called the support structure. The quality of foundation pit support is crucial to the entire foundation pit construction project. If the foundation pit support fails to meet the relevant requirements, it may cause serious engineering accidents.

[0004] The main types of foundation pit support structures are as follows: slope excavation and simple support, cement-soil gravity retaining structure, soil nailing wall and composite soil nailing wall retaining structure, steel sheet pile retaining structure, cast-in-place concrete pile structure, diaphragm wall retaining structure, portal frame retaining structure, etc. Different support methods can be adopted according to different actual conditions. Among them, cast-in-place concrete pile structures are generally divided into five types, mainly: prestressed concrete pipe piles, manually excavated cast-in-place piles, long spiral drilled cast-in-place piles, rotary drilled cast-in-place piles, and vibratory driven pipe piles.

[0005] The common problems with current construction techniques are: when these concrete pile structures require meshing and shotcreting between each concrete pile, it is necessary to drill holes and drive in short nails, which requires re-drilling the pile body, thus damaging the integrity of the pile body; the non-removable connection system between piles results in low material utilization and a lot of waste. Utility Model Content

[0006] The technical problem this utility model aims to solve is to overcome the shortcomings and defects mentioned in the background art above, and to provide a mud-walled cast-in-place pile foundation pit support structure that does not require secondary drilling and has a detachable and reusable pile connection system. To solve the above technical problem, the technical solution proposed by this utility model is as follows:

[0007] A mud-wall cast-in-place pile foundation pit support structure includes: cast-in-place piles, which are formed by pile reinforcement and concrete pouring. The pile reinforcement includes longitudinally uniformly distributed main bars, spiral stirrups spirally wound around the outside of the main bars, reinforcing stirrups welded at intervals to the outside of the main bars, supporting bars welded to the inside of the reinforcing stirrups, and slots welded to the side of the main bars near the foundation pit to be excavated.

[0008] A detachable short nail, detachably connected to a slot, includes an attachment plate, a short nail head fixed to the attachment plate, and a short nail multi-directional hook detachably connected to the short nail head;

[0009] The connection system includes a buckle that mates with the slot and connecting steel bars for connecting adjacent cast-in-place piles;

[0010] Drainage ditch, attached to the connecting steel bars, includes a water trough, which intercepts and discharges surface water and seepage water inside and outside the foundation pit.

[0011] In one embodiment, the supporting rib is welded in a triangular shape to the inside of the reinforcing stirrup to form a deformation-resistant triangular support.

[0012] In one embodiment, the attached steel plate is embedded inside the slot.

[0013] In one embodiment, the short nail multi-directional hook consists of a bolt end, a short nail inclined end, and a circular base support. The circular base support is located between the bolt end and the short nail inclined end. Both the bolt end and the short nail inclined end are connected to the circular base support. The short nail inclined end is provided with an external thread, and the circular base support is provided with a matching internal thread. The short nail multi-directional hook and the circular base support are detachably connected by threads to form a multi-directional force support point of the bracing system.

[0014] In one embodiment, before the connecting system is connected to the slot, a removable baffle is provided at the buckle position inside the slot, and the shape of the removable baffle is consistent with the buckle of the connecting system.

[0015] In one embodiment, the drainage ditch is a movable drainage ditch, and also includes a locking device on the water tank and a connection port at both ends of the water tank. The two adjacent sections of the movable drainage ditch can be detachably connected by the cooperation of the connection ports.

[0016] In one embodiment, the latch is an arc-shaped latch, and multiple movable drainage channels are hooked onto the connecting steel bars through the latch to form a continuous drainage channel.

[0017] In one embodiment, the movable drainage ditch is an overall triangular prism structure.

[0018] Compared with the prior art, the beneficial effects of this utility model are as follows: In the above-mentioned mud-wall cast-in-place pile foundation pit support structure, when making pile reinforcement, the detachable short nails are detachably connected to the slots of the pile reinforcement. The pre-embedded slot design avoids the secondary drilling of the pile body before meshing in the traditional process, simplifying the construction process while maintaining the complete pile structure and improving construction convenience; the composite structure of support bars and spiral stirrups enhances the pile's resistance to deformation, and the inter-pile mesh structure formed by the connection system significantly improves the overall stability of the support system; the modular and detachable design enables the recycling and reuse of detachable short nails, connection systems, and drainage ditches, and the rapid assembly drainage system reduces the amount of earthwork excavation, forming a component recycling system and further reducing construction costs. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the three-dimensional structure of the mud-wall cast-in-place pile foundation pit support structure placed in the foundation pit according to one embodiment.

[0021] Figure 2 This is a schematic diagram of the three-dimensional structure of the cast-in-place pile in one embodiment of the mud wall protection cast-in-place pile foundation pit support structure.

[0022] Figure 3 This is a three-dimensional structural diagram of the mud wall grouting pile foundation pit support structure before the slot and detachable short nail are connected when it is placed into the foundation pit, according to one embodiment.

[0023] Figure 4 This is a three-dimensional structural diagram of a mud-wall cast-in-place pile foundation pit support structure after the groove in the cast-in-place pile is connected with a detachable short nail, according to one embodiment.

[0024] Figure 5 This is a top view of a mud-wall grouting pile foundation pit support structure according to one embodiment;

[0025] Figure 6 This is a schematic diagram of the use of a mud-wall grouting pile foundation pit support structure in one embodiment;

[0026] Figure 7 This is a schematic diagram of the mesh reinforcement structure for a mud-wall cast-in-place pile foundation pit, as described in one embodiment.

[0027] Figure 8This is a schematic diagram of a detachable short nail shaft structure according to one embodiment, where (a) is a front view and (b) is a sectional view.

[0028] (c) is a cross-sectional view from another perspective;

[0029] Figure 9 This is a schematic diagram of a drainage ditch structure according to one embodiment.

[0030] Attached reference numerals: 1: Cast-in-place pile; 2: Pile reinforcement; 2.1: Continuous main reinforcement; 2.2: Spiral stirrup; 2.3: Reinforcing stirrup; 2.4: Supporting reinforcement; 2.5: Slot; 3: Removable short nail; 3.1: Attached steel plate; 3.2: Short nail head; 3.3: Short nail multi-directional hook; 3.3.1: Bolt end; 3.3.2: Circular bottom support; 3.3.3: Short nail oblique end; 4: Connection system; 4.1: Buckle; 4.2: Connecting reinforcement; 5: Drainage ditch; 5.1: Water trough; 5.2: Clip; 5.3: Connection port; 6: Removable baffle; 7: Grouting port; 8: Pile pit. Detailed Implementation

[0031] To facilitate understanding of this utility model, the following description will be more comprehensive and detailed in conjunction with the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.

[0032] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention.

[0033] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0034] Please see Figure 1-9One embodiment of the mud-wall cast-in-place pile foundation pit support structure mainly includes: cast-in-place piles 1 formed by pile reinforcement 2 and concrete pouring, detachable short nails 3, a connection system 4, and a drainage ditch 5. Specifically, a pile pit 8 is excavated at the required support location around the foundation pit using a spiral drilling pile driver. After placing the pile reinforcement 2 at the center of the pile pit 8, concrete is poured to form the cast-in-place pile 1. The pile reinforcement 2 includes a continuous main bar 2.1, spiral stirrups 2.2, reinforcing stirrups 2.3, and supporting bars 2.4. A slot 2.5 is provided on the side of the pile reinforcement 2 near the foundation pit, and the slot 2.5 is equipped with detachable short nails 3. The detachable short nail 3 includes an attachment steel plate 3.1 fixed in the slot 2.5, a short nail head 3.2 fixed on the attachment steel plate 3.1, and a short nail multi-directional hook 3.3 detachably connected to the short nail head 3.2. The short nail multi-directional hook 3.3 is bolted to the short nail head 3.2 to achieve a detachable connection. The attached steel plate 3.1 and the pile reinforcement 2 form a whole, so there is no need to drill a second hole in the pile body for the already covered concrete cast-in-place pile 1, the structure is not damaged and the integrity is better.

[0035] The short-pronged multi-directional hook 3.3 includes a bolt end 3.3.1, a circular base support 3.3.2, and a short-pronged angled end 3.3.3. The circular base support 3.3.2 is located between the bolt end 3.3.1 and the short-pronged angled end 3.3.3. Both the bolt end 3.3.1 and the short-pronged angled end 3.3.3 are connected to the circular base support 3.3.2. The short-pronged angled end 3.3.3 has external threads, and the circular base support 3.3.2 has matching internal threads. The two are detachably connected by threads. After the foundation pit is completed, the angled bracing system can be fitted onto the short-pronged angled end 3.3.3, with the bottom supported on the circular base support 3.3.2, forming a multi-directional force support point for the angled bracing system. After the foundation pit is completed, the angled bracing system can be fitted onto the short-pronged angled end 3.3.3, with the bottom supported on the circular base support 3.3.2, making construction safer.

[0036] Specifically, in one embodiment, the continuous main reinforcement 2.1 is evenly distributed along the longitudinal direction of the cast-in-place pile 1, and its length is determined according to the depth of the foundation pit, usually slightly larger than the design length of the cast-in-place pile 1 to ensure effective anchorage. Reinforcing stirrups 2.3 are arranged at intervals along the outer side of the continuous main reinforcement 2.1. Preferably, the support reinforcement 2.4 has a triangular structure and is welded to the inner side of the reinforcing stirrup 2.3 to enhance structural rigidity. Spiral stirrups 2.2 are evenly distributed spirally upwards around the outer side of the continuous main reinforcement 2.1, forming a three-dimensional constraint. A slot 2.5 is fixed to the outer side of the continuous main reinforcement 2.1 for rapid positioning and installation of subsequent support components. The continuous main reinforcement 2.1, spiral stirrups 2.2, reinforcing stirrups 2.3, support reinforcement 2.4, and slot 2.5 are welded together to form an integral load-bearing structure, ensuring the coordinated deformation capacity of the pile body under construction loads.

[0037] Specifically, when making the pile reinforcement 2, the inner groove of the attached steel plate 3.1 is plugged with rubber to prevent cement from blocking it when pouring cement. After the foundation pit is excavated, the plug rubber is removed and the bolt end 3.3.1 of the short nail multi-directional hook 3.3 is screwed on.

[0038] Specifically, the connection system 4 includes connecting steel bars 4.2 and buckles 4.1 fixed at both ends. The buckles are connected to the slots 2.5, and the two cast-in-place piles 1 are connected through the connection system 4. The connection system 4 connects the two cast-in-place piles 1, so that each pile is directly connected, making it more stable. In addition, the connecting steel bars 4.2 make the steel mesh of the mesh surface less likely to fall off, ensuring the stability of the mesh surface.

[0039] Preferably, the drainage ditch 5 is a movable drainage ditch, including a water trough 5.1, a locking opening 5.2 disposed on the water trough 5.1, and a connecting opening 5.3 disposed at the end of the water trough 5.1. Preferably, in one embodiment, the drainage ditch 5 is generally in the form of a triangular prism structure. It can be inserted into an excavated foundation pit without the need for large-scale civil engineering excavation work. Preferably, the locking opening 5.2 is an arc-shaped piece that can be hung on a connecting steel bar, and two drainage ditches 5 can be connected into an integral drainage structure through the connecting opening 5.3.

[0040] Preferably, during the initial construction phase when fabricating the pile reinforcement 2, the slot 2.5 needs to be covered by a removable baffle 6 to protect the connection node. Therefore, the removable baffle 6 is placed inside the slot 2.5 at the buckle 4.1 position, and its shape is consistent with the buckle 4.1. After excavating the foundation pit in layers, the removable baffle 6 is removed layer by layer from top to bottom and replaced with the connecting reinforcement 4.2. The rigid connection can ensure that the steel mesh on the hanging mesh surface is not easy to fall off, thus improving stability. Preferably, the removable baffle is a wooden baffle.

[0041] The working process of the above-mentioned mud-wall cast-in-place pile foundation pit support structure is as follows: Determine the location of the pile pits to be supported around the foundation pit, and excavate the pile pits 8 around the foundation pit using a spiral drilling pile driver. Simultaneously, fabricate the pile reinforcement 2. It is necessary to ensure that the diameter of the pile pit 8 is slightly larger than the diameter of the pile reinforcement 2. The specific value needs to be calculated according to the actual situation. When fabricating the pile reinforcement 2, the longitudinal main reinforcement 2.1 is evenly distributed on the outside of the reinforcing stirrup 2.3, and the supporting reinforcement 2.4 is welded to the inside of the reinforcing stirrup 2.3 in a triangular structure. The spiral stirrup 2.2 spirally wraps around the longitudinal main reinforcement 2.1 to form a three-dimensional constraint. Finally, the steel slot 2.5 is pre-welded to the longitudinal main reinforcement 2.1 near the foundation pit side. After completing the fabrication of the pile reinforcement 2, the pile reinforcement 2 is vertically placed into the pile pit 8, and concrete is poured through the grouting port 7 to form the cast-in-place pile 1. The slot 2.5 is oriented towards the foundation pit side. The slot 2.5 is connected with a detachable short nail 3 and equipped with a detachable baffle 6. Next, excavation is carried out layer by layer from top to bottom. After each layer is excavated, the rubber inside the nut-shaped groove of the short nail head 3.2 on the detachable short nail 3 is removed. The wire mesh is then hung on the detachable short nail 3, and the bolt end 3.3.1 of the multi-directional hook 3.3 of the short nail is screwed on. Then, the detachable baffle 6 is removed layer by layer. The slots 2.5 of the adjacent cast-in-place piles 1 are fastened to the buckles 4.1 through the connecting system 4. The connecting steel bars 4.2 form a mesh structure between adjacent piles. The bottom detachable baffle 6 of each layer is not removed for the time being, and the connecting system 4 is not connected for the time being. Then, the mixed concrete slope protection surface is sprayed onto the excavation surface. After that, the bottom detachable baffle 6 of each layer is removed according to the above steps, and the corresponding connecting system 4 is connected. Next, the drainage ditch 5 is inserted into the hanging mesh surface, and the buckle 5.2 is fixed to the bottom connecting steel bar 4.2. All the connecting ports 5.3 are connected to make the drainage ditch 5 a whole, realizing seepage water collection. After the foundation pit is excavated, one end of the inclined support is fixed to the scaffolding of the proposed structure, and the other end is fitted with the inclined end of the short nail 3.3.3. The end abuts against the circular bottom support 3.3.2 to form a stable support. During backfilling, the short nail multi-directional hook 3.3 is removed layer by layer from bottom to top by rotating in the opposite direction. At the same time, the drainage ditch 5 is removed to realize the recycling of components.

[0042] This mud-wall cast-in-place pile foundation pit support structure replaces traditional secondary drilling with a slot-embedded structure that uses the slot 2.5 of the pile reinforcement 2 to pre-embed detachable short nails 3, ensuring pile integrity and simplifying connection procedures. The short nail multi-directional hooks 3.3, connection system 4, and drainage ditch 5 form a detachable modular support component, enabling dismantling, recycling, and reuse after use. In the pile reinforcement 2, triangular support bars 2.4 and spiral stirrups 2.2 work together to enhance the pile's resistance to deformation, while the inter-pile mesh connection system 4 improves overall stability. The circular bottom support 3.3.2 of the short nail multi-directional hooks 3.3 provides multi-directional force support points for the diagonal bracing, reducing the risk of support failure and enhancing safety performance. The modular and detachable design allows for the recycling and reuse of the short nail components, connection system, and prefabricated drainage ditch. Combined with a rapid assembly drainage system, this reduces earthwork excavation, forming a component recycling system and further reducing construction costs.

[0043] The above description is merely an embodiment of this utility model and does not limit the patent scope of this utility model. Any equivalent structural or procedural transformations made based on the content of this utility model specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this utility model.

Claims

1. A slurry wall bored pile foundation pit support structure characterized by, include: A cast-in-place pile is formed by pouring concrete with pile reinforcement bars. The pile reinforcement bars include longitudinally evenly distributed main bars, spiral stirrups spirally wound around the outside of the main bars, reinforcing stirrups welded at intervals to the outside of the main bars, supporting bars welded to the inside of the reinforcing stirrups, and slots welded to the side of the main bars near the excavation pit. A detachable short nail, detachably connected to a slot, includes an attachment plate, a short nail head fixed to the attachment plate, and a short nail multi-directional hook detachably connected to the short nail head; The connection system includes a buckle that mates with the slot and connecting steel bars for connecting adjacent cast-in-place piles; Drainage ditch, attached to the connecting steel bars, includes a water trough, which intercepts and discharges surface water and seepage water inside and outside the foundation pit.

2. The mud-wall cast-in-place pile foundation pit support structure according to claim 1, characterized in that, The supporting ribs are welded in a triangular shape to the inside of the reinforcing stirrups to form a deformation-resistant triangular support.

3. The mud-wall cast-in-place pile foundation pit support structure according to claim 1, characterized in that, The attached steel plate is embedded inside the slot.

4. The mud-wall cast-in-place pile foundation pit support structure according to claim 1, characterized in that, The short nail multi-directional hook consists of a bolt end, a short nail inclined end, and a circular base support. The circular base support is located between the bolt end and the short nail inclined end. Both the bolt end and the short nail inclined end are connected to the circular base support. The short nail inclined end is provided with external threads, and the circular base support is provided with matching internal threads. The short nail multi-directional hook and the circular base support are detachably connected by threads to form a multi-directional force support point of the bracing system.

5. The mud-wall cast-in-place pile foundation pit support structure according to claim 1, characterized in that, Before the connecting system is connected to the card slot, a removable baffle is provided at the buckle position inside the card slot, and the shape of the removable baffle is consistent with the buckle of the connecting system.

6. The mud-wall cast-in-place pile foundation pit support structure according to claim 1, characterized in that, The drainage ditch is a movable drainage ditch, and also includes a clamp on the water tank and a connection port at both ends of the water tank. Through the cooperation of the connection ports, two adjacent movable drainage ditch sections can be detachably connected.

7. The mud-wall cast-in-place pile foundation pit support structure according to claim 6, characterized in that, The latch is an arc-shaped latch, and multiple movable drainage channels are attached to the connecting steel bars through the latch to form a continuous drainage channel.

8. The mud-wall cast-in-place pile foundation pit support structure according to claim 6, characterized in that, The movable drainage ditch has a triangular prism structure.

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