A drilling and pouring rock-socketed pile foundation structure for a spoil site and a construction method thereof

Abstract

The application provides a bored cast-in-situ rock-socketed pile foundation structure of a waste dump, which comprises steel mesh, oil felt, positioning steel bars and a bored cast-in-situ rock-socketed pile foundation. The bored cast-in-situ rock-socketed pile foundation is embedded in a filling area on the waste dump and extends into bedrock, and a steel casing is reserved at the end of the bored cast-in-situ rock-socketed pile foundation away from the bedrock. The steel mesh is arranged between the bored cast-in-situ rock-socketed pile foundation and a retaining wall of the filling area, and the positioning steel bars are arranged on the steel mesh. The oil felt is sleeved on the steel mesh and is bound with the steel mesh by lashing wires. The construction method comprises the following steps: the site of the waste dump is leveled to ensure smooth roads and the positioning of the bored cast-in-situ rock-socketed pile foundation to ensure the accuracy of the construction position; firstly, mouth locking pouring is performed, a hoisting device is installed, the steel casing reserved on the top of the pile foundation is punched, then a pile hole is excavated to the designed depth by using a drilling machine; and the bored cast-in-situ rock-socketed pile foundation structure of the waste dump is assembled.

Description

Technical Field

[0001] The present invention belongs to the field of foundation engineering or other related structural components, and particularly relates to a bored and cast-in-place rock-embedded pile foundation structure for an abandoned soil field and a construction method thereof. Background Art

[0002] With the continuous development of foundation engineering projects under various complex geological conditions, the harmful effects of negative friction in pile foundations have become increasingly apparent. Methods to reduce this negative friction have attracted extensive attention and research. This is particularly true for post-fill loading, which can easily cause significant pile-soil settlement. The resulting negative friction poses a significant safety hazard to the normal operation of pile foundations. During the construction of pile foundations in abandoned soil fields, the soil surrounding the piles will undergo corresponding settlement and displacement. The pile foundations will also experience corresponding settlement and displacement due to factors such as superstructure loads. When the displacement of the soil surrounding the piles exceeds the displacement of the pile body, the pile body tends to move upward relative to the soil. At this point, the soil surrounding the piles exerts a downward pull on the pile foundation, which is known as negative friction in the pile foundation. This negative friction reduces the bearing capacity of the pile foundation, increases settlement, and, in more serious cases, can lead to failure and instability, posing a safety hazard. Therefore, it is necessary to design appropriate technical devices to reduce the negative friction in pile foundations, thereby minimizing its harmful effects on the pile foundation, avoiding certain safety hazards, and improving safety performance.

[0003] Application Publication No. CN216339501U discloses a device for eliminating negative friction in pile foundations and its technical solution. The device comprises a cast-in-place pile column, wherein the outer surface of the cast-in-place pile column is sheathed with an inner casing, and the outer surface of the inner casing is sheathed with a casing base and a sealing unloading sleeve. The casing base is located below the neutral point of the cast-in-place pile column, and the sealing unloading sleeve is located above the neutral point of the cast-in-place pile column. The outer surface of the casing base is provided with a plurality of positioning holes, and the interiors of the positioning holes are connected to embedded foundation columns. The outer surface of the inner casing is sheathed with an outer casing, and a gap is provided between the inner casing and the outer casing. The embedded foundation columns generate an upward resistance to the outer casing, thereby relatively reducing its negative friction. At the same time, the outer casing, through the lubricating material between the outer casing and the inner casing, can reduce the friction between the outer casing and the inner casing, thereby better eliminating negative friction, making the pile foundation construction more stable and improving the safety of the building construction.

[0004] Publication No. 110158585A discloses a device and construction method for reducing negative friction in pile foundations in soft soil areas. The device comprises an inner casing, a negative friction tube, and an outer casing. The negative friction tube and the inner casing are connected by a rubber seal at the bottom and spaced-apart blocks around them. This method utilizes the inverted tapered negative friction tube to increase the vertical bearing capacity of vertically loaded pile foundations. The larger diameter of the negative friction tube relative to the pile foundation also increases the pile foundation's ability to withstand horizontal loads. The combined negative friction tube and inner casing allows the pile foundation and the negative friction tube to slide relative to each other, reducing negative friction caused by excessive soil settlement around the pile.

[0005] Application Publication No. CN102628269A discloses a technical device and method for reducing the negative friction of cast-in-place piles. The device uses static pressure or vibration to sink a double-layer steel casing, along with a plastic film and an annular preform, to a pre-designed depth. Once the concrete of the cast-in-place pile reaches a certain strength, the steel casing is removed from the ground, while the double-layer plastic film and annular preform remain in the foundation. This reduces the friction coefficient at the pile-soil interface above the pile's neutral point, eliminates the harmful effects of negative friction in the pile foundation, and improves the pile's bearing capacity. While feasible, these methods all suffer from expensive materials, complex assembly, and installation difficulties. Summary of the Invention

[0006] The present invention provides a bored cast-in-place rock-socketed pile foundation structure for an abandoned soil field, comprising a steel mesh, tarpaulin, positioning steel bars and a bored cast-in-place rock-socketed pile foundation;

[0007] The bored cast-in-place rock-embedded pile foundation is buried in the fill area on the spoil site and extends into the bedrock, and a steel casing is reserved at the end of the bored cast-in-place rock-embedded pile foundation away from the bedrock;

[0008] The steel mesh is arranged between the bored cast-in-place rock-embedded pile foundation and the retaining wall of the fill area, and positioning steel bars are arranged on the steel mesh;

[0009] The tarpaulin sleeve is arranged on the steel wire mesh and is bound to the steel wire mesh through binding wires.

[0010] Optionally, the portion of the steel mesh in contact with the positioning steel bars is bounded along the pile body direction of the bored cast-in-place rock-embedded pile foundation using a plurality of tying wires, and the distance between two adjacent tying wires is set to 20 mm-50 mm.

[0011] Optionally, the diameter of the steel wire in the wire mesh is set to 1mm-2mm, and the mesh diameter is set to 1mm-5mm; the binding wire is a steel wire with a diameter of 0.7mm-1.2mm and a length of 200mm-500mm.

[0012] Optionally, the felt is configured as a felt structure with an asphalt layer coated on the surface, and the thickness of the asphalt layer is configured to be 5 mm to 10 mm.

[0013] Optionally, a hook is provided on one end of the positioning steel bar close to the steel casing.

[0014] Optionally, the diameter of the positioning steel bar is set to 10mm-20mm, and the positioning steel bar is provided with four bars arranged in a circular array along the circumference of the steel casing; the length of the hook is set to 20mm-40mm.

[0015] Optionally, a plurality of stirrups spaced apart from each other are provided on the wire mesh, the spacing between two adjacent stirrups is set to 200mm-500mm, and hooks are provided at the joints between the stirrups.

[0016] Optionally, the diameter of the stirrups is set to 6mm-12mm; the circumferential diameter of the stirrups should be set to 20mm-50mm smaller than the diameter of the steel cage; and the length of the hook is set to 20mm-30mm.

[0017] The present invention also provides a construction method for a bored cast-in-place rock-embedded pile foundation structure in an abandoned soil field, comprising the following steps:

[0018] Preparation work: The site of the spoil dump is horizontally moved to ensure that the road is clear, and the bored cast-in-place rock-embedded pile foundation is positioned to ensure the construction location is accurate;

[0019] Pile hole construction: First, the locking casting is carried out, the lifting device is installed, and the steel casing reserved on the top of the pile foundation is driven in. Then, the pile hole is excavated to the designed depth using a drilling rig. After that, it is necessary to avoid the hole collapse phenomenon, that is, the hole cleaning and acceptance work of the excavated part should be carried out in a timely and orderly manner;

[0020] The above-mentioned bored cast-in-place rock-embedded pile foundation structure of the abandoned soil field is assembled.

[0021] Optionally, the detailed process for assembling the bored cast-in-place rock-socketed pile foundation structure in the spoil site is as follows:

[0022] 1) Select the size of the wire mesh, the length of the positioning steel bars and the size of the felt that are suitable for the diameter of the reinforcement cage in the specific project practice;

[0023] 2) steel wire mesh and linoleum are tied together according to designing 2-4 rows along the pile body direction between the positioning steel bar place and two positioning steel bars and the distance between its adjacent two tying wires is set to 20mm-50mm with tying wire along the pile body direction, afterwards the positioning steel bar and the steel wire mesh contact portion tied together with linoleum are tied together according to being set to 20mm-50mm with tying wire along the pile body direction; The three can be coated with asphalt construction work on linoleum after being tied up mutually, after the asphalt on the linoleum is coated along the pile body direction, its whole body can be wrapped in the outer periphery of the reinforcement cage connected by welding, now, just can need to set the hook at certain spacing of stirrups and the stirrup junction along the pile body direction, the spacing between adjacent two stirrups is 200mm-500mm and the circumferential diameter of stirrups should be set to 20mm-50mm less than reinforcement cage diameter, and the upper end of the positioning steel bar is designed to hook shape, it just hangs on the reserved steel casing and prevents falling dislocation;

[0024] 3) After completing steps 1) and 2), hoist the steel cage together with the asphalt-coated felt wrapped around it. During hoisting, the installation should be slow and steady to prevent the pile foundation negative friction reduction device from falling loose.

[0025] 4) After the steel cage is hoisted and fixed, and the hook at the upper end of the positioning steel bar is hung on the steel casing to prevent it from falling and dislocating, the concrete prepared on the ground should be transported to the pile hole using a conduit. The conduit slowly transports the concrete into the pile hole. During the transportation process, the concrete will shake up and down in the pile hole, which can automatically untie the special hook originally at the junction of the stirrups, so that it can be laid neatly on the inner side of the retaining wall;

[0026] 5) Continue the concrete delivery construction work. When the pouring is almost completed, the hook hanging on the steel casing should be clamped off or hammered straight, and the reserved steel casing should be removed;

[0027] 6) After the concrete pouring is completed, the bored cast-in-place rock-embedded pile foundation structure of the abandoned soil field is in normal operation. When the soil in the fill area around the pile foundation sinks, the asphalt coated on the felt and fixed on the wire mesh plays its role in reducing the negative friction resistance of the pile foundation.

[0028] Compared with the prior art, the present invention has the following beneficial effects:

[0029] The bored and cast-in-place rock-embedded pile foundation structure provided by the present invention is provided with stirrups along the pile body direction on the periphery of the steel cage during operation, and special hooks are provided at the joints of the stirrups, so that the bored and cast-in-place rock-embedded pile foundation structure will not become loose when it is placed in the drill hole; because the steel cage will be placed under the bedrock layer and the designed depth of the bored and cast-in-place rock-embedded pile foundation structure is the height between the ground and the bedrock, the up and down shaking of the steel cage during the pouring of concrete will cause the hooks of the overlapping parts of the bored and cast-in-place rock-embedded pile foundation structure to be automatically untied, and then the hooks will be pressed against the inner side of the retaining wall due to the tension during the untying, so as to prevent the pile from becoming loose when it is placed in the drill hole. The use of asphalt to reduce the negative friction of pile foundations can reduce the negative friction of pile foundations caused by the corresponding settlement displacement difference between the soil around the piles and the pile foundations. It has the characteristics of simple structural design, standardized components, stable and fast installation, low cost, common materials, convenient construction, and the ability to adjust the corresponding design dimensions according to actual engineering design, convenience and flexibility. It can also greatly reduce the negative friction of pile foundations caused by the settlement of the fill area in the spoil site, reduce the corresponding pull-down load, increase the bearing capacity of the pile foundation, and make the construction of the pile foundation more stable, thereby greatly improving the safety of the corresponding building construction.

[0030] In addition to the above-described objects, features and advantages, the present invention has other objects, features and advantages. The present invention will be further described in detail below with reference to the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] The accompanying drawings, which constitute part of this application, are intended to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are intended to explain the present invention and do not constitute an undue limitation of the present invention. In the accompanying drawings:

[0032] Figure 1 This is a schematic structural diagram of a bored cast-in-place rock-embedded pile foundation structure for an abandoned soil field according to an embodiment of the present invention;

[0033] Figure 2 yes Figure 1 Expanded view of the steel wire mesh and positioning steel bars.

[0034] Figure 3 The design is a detailed diagram of the location of the wire mesh, positioning steel bars, linoleum and asphalt in this design installation;

[0035] Figure 4 The design is a drawing of the stirrups on the wire mesh in this design device;

[0036] Figure 5 The design is a detailed drawing of the hooks at the junction of the stirrups on the wire mesh in this design device.

[0037] in:

[0038] 1. Wire mesh, 2. Roofing felt, 3. Positioning steel bars, 4. Fill area, 5. Bedrock, 6. Pile foundation. DETAILED DESCRIPTION

[0039] In order to make the above-mentioned purposes, features and advantages of the present invention more clear and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings. It should be noted that the drawings of the present invention are all simplified and non-precisely scaled, and are only used to conveniently and clearly assist in explaining the implementation of the present invention; the "numbers" mentioned in the present invention are not limited to the specific quantities in the examples in the accompanying drawings; the directions or positional relationships indicated by "front", "middle", "back", "left", "right", "up", "down", "top", "bottom", "middle", etc. mentioned in the present invention are based on the directions or positional relationships shown in the drawings of the present invention, and do not indicate or imply that the devices or components referred to must have a specific direction, nor can they be understood as limitations on the present invention.

[0040] This embodiment:

[0041] See also Figures 1 to 5 As shown, the present invention provides a bored cast-in-place rock-socketed pile foundation structure for a spoil site, specifically a bored cast-in-place rock-socketed pile foundation structure for a spoil site, comprising a steel mesh 1, tarpaulin 2, positioning steel bars 3 and a bored cast-in-place rock-socketed pile foundation 6;

[0042] The bored cast-in-place rock-embedded pile foundation 6 is buried in the fill area 4 on the spoil site and extends into the bedrock 5, and a steel casing is reserved at the top of the bored cast-in-place rock-embedded pile foundation 6 (i.e., the end away from the bedrock 5);

[0043] The steel mesh 1 is arranged between the bored cast-in-place rock-embedded pile foundation 6 and the retaining wall of the fill area 4, and a positioning steel bar 3 is provided on the steel mesh 1;

[0044] The tarpaulin 2 is sleeved on the steel mesh 1 and is bound to the steel mesh 1 by binding wires.

[0045] Optionally, the part where the wire mesh 1 contacts the positioning steel bars 3 is tied with a plurality of ties along the pile body direction of the bored cast-in-place rock-embedded pile foundation 6, and the distance between two adjacent ties is set to 20mm-50mm; and 2-4 rows of ties are arranged along the pile body of the bored cast-in-place rock-embedded pile foundation 6 at 1 / 4 of the circumference between two adjacent positioning steel bars 3, and the distance between each row of ties is set to 20mm-50mm.

[0046] Optionally, the diameter of the steel wire in the steel mesh 1 is set to 1mm-2mm, and the mesh diameter is set to 1mm-5mm; the binding wire is preferably a steel wire with a diameter of 0.7mm-1.2mm and a length of 200mm-500mm.

[0047] Optionally, the felt 2 is preferably configured as a felt structure with an asphalt layer coated on the surface, and the thickness of the asphalt layer is preferably set to 5mm-10mm.

[0048] Optionally, a hook is provided on the end of the positioning steel bar 3 near the steel casing. By connecting the hook to the steel casing, the positioning steel bar 3 can be prevented from falling or being misplaced. Preferably, the diameter of the positioning steel bar 3 is set to 10 mm to 20 mm, and four positioning steel bars 3 are preferably arranged in an array along the circumference of the steel casing. The length of the hook is preferably set to 20 mm to 40 mm.

[0049] Optionally, a plurality of stirrups spaced apart from each other are provided on the wire mesh 1, and the spacing between two adjacent stirrups is preferably set to 200mm-500mm, and hooks are provided at the junction of the stirrups, so that the tarpaulin 2 and the wire mesh 1 do not become loose when placed in the drilled hole, and the vibration generated when pouring concrete can automatically unhook the hooks on the wire mesh 1, so that the tarpaulin 2 is laid neatly on the inner side of the retaining wall of the fill area 4. Preferably, the diameter of the stirrups is preferably set to 6mm-12mm; the circumferential diameter of the stirrups should be set to 20mm-50mm smaller than the diameter of the steel cage (specifically, the steel cage here is an auxiliary structure provided as needed during the construction process, and specific reference is made to the prior art); the length of the hooks is preferably set to 20mm-30mm.

[0050] The construction method of the above-mentioned abandoned soil field bored cast-in-place rock-embedded pile foundation structure is as follows:

[0051] S1. Preparation: The site of the spoil dump is horizontally moved to ensure that the road is clear, and the bored cast-in-place rock-embedded pile foundation is positioned to ensure the construction location is accurate;

[0052] S2, pile hole construction: first, the lock casting is carried out, the lifting device is installed, and the steel casing reserved on the top of the pile foundation is driven in (specifically, the steel casing here is an auxiliary structure set up as needed during the construction process, and specific reference is made to the existing technology). Then, the pile hole is excavated to the designed depth using a drilling rig. After that, it is necessary to avoid the hole collapse phenomenon, that is, the hole cleaning and acceptance work of the excavated part should be carried out in a timely and orderly manner;

[0053] S3. Assemble the above-mentioned bored cast-in-place rock-embedded pile foundation structure in the spoil field. The specific assembly process is as follows:

[0054] 1) Select the size of the wire mesh, the length of the positioning steel bars and the size of the felt that are suitable for the diameter of the reinforcement cage in the specific project practice;

[0055] 2) Tie the wire mesh and the felt together with the tying wire in 2-4 rows along the pile direction between the positioning steel bars and the two positioning steel bars, and set the distance between the two adjacent tying wires to be 20mm-50mm along the pile direction. Then tie the contact part of the positioning steel bars and the wire mesh that has been tied with the felt with the tying wire along the pile direction, and set the distance between the two adjacent tying wires to be 20mm-50mm. After the three are tied together, the asphalt coating work can be carried out on the felt. After the asphalt is coated on the felt along the pile direction, it can be wrapped around the outer periphery of the steel cage that has been connected by welding. At this time, stirrups need to be set at a certain interval along the pile direction and hooks are used at the joints of the stirrups (see Figure 5 As shown), the spacing between two adjacent stirrups is 200mm-500mm and the circumferential diameter of the stirrups should be set to be 20mm-50mm smaller than the diameter of the steel cage, and the upper end of the positioning steel bar is designed to be hook-shaped, which can be hung on the reserved steel casing to prevent it from falling and dislocating;

[0056] 3) After completing steps 1) and 2), hoist the steel cage together with the asphalt-coated felt wrapped around it. During hoisting, the installation should be slow and steady to prevent the pile foundation negative friction reduction device from falling loose.

[0057] 4) After the steel cage is hoisted and fixed, and the hook at the upper end of the positioning steel bar is hung on the steel casing to prevent it from falling and dislocating, the concrete prepared on the ground should be transported to the pile hole using a conduit. The conduit slowly transports the concrete into the pile hole. During the transportation process, the concrete will shake up and down in the pile hole, which can automatically untie the special hook originally at the junction of the stirrups, so that it can be laid neatly on the inner side of the retaining wall;

[0058] 5) Continue the concrete delivery construction work. When the pouring is almost completed, the hook hanging on the steel casing should be clamped off or hammered straight, and the reserved steel casing should be removed;

[0059] 6) After the concrete pouring is completed, the bored cast-in-place rock-embedded pile foundation structure of the abandoned soil field is in normal operation. When the soil in the fill area around the pile foundation sinks, the asphalt coated on the felt and fixed on the wire mesh plays its role in reducing the negative friction resistance of the pile foundation.

[0060] In the normal working state mechanism of the bored cast-in-place rock-embedded pile foundation structure in the above-mentioned abandoned soil field, because when pouring concrete, the up and down vibration of the concrete will automatically unhook the hooks of the overlapping parts of the wire mesh coated with asphalt felt, so that it can be laid on the inner side of the retaining wall. Therefore, when the soil in the fill area around the pile foundation sinks, the asphalt coated on the felt laid on the inner side of the retaining wall plays its role in reducing the negative friction resistance of the pile foundation.

[0061] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention shall be included within the scope of protection of the present invention.

Claims

1. A method for bored and cast-in-place rock-embedded pile foundation in an abandoned soil field, characterized in that: The bored cast-in-place rock-embedded pile foundation structure of the abandoned soil site includes a steel mesh (1), roofing felt (2), positioning steel bars (3) and a bored cast-in-place rock-embedded pile foundation (6); The bored cast-in-place rock-embedded pile foundation (6) is buried in the fill area (4) on the spoil site and extends into the bedrock (5), and a steel casing is reserved at the end of the bored cast-in-place rock-embedded pile foundation (6) away from the bedrock (5); The steel mesh (1) is arranged between the bored cast-in-place rock-embedded pile foundation (6) and the retaining wall of the fill area (4), and positioning steel bars (3) are provided on the steel mesh (1); The tarpaulin (2) is sleeved on the steel mesh (1) and is tied to the steel mesh (1) through tying wires; The construction method of the bored cast-in-place rock-embedded pile foundation structure in the spoil site comprises the following steps: Preparation work: The site of the spoil dump is horizontally moved to ensure that the road is clear, and the bored cast-in-place rock-embedded pile foundation is positioned to ensure the construction location is accurate; Pile hole construction: First, the locking casting is carried out, the lifting device is installed, and the steel casing reserved on the top of the pile foundation is driven in. Then, the pile hole is excavated to the designed depth using a drilling rig. After that, it is necessary to avoid the hole collapse phenomenon, that is, the hole cleaning and acceptance work of the excavated part should be carried out in a timely and orderly manner; Assembling the above-mentioned bored cast-in-place rock-embedded pile foundation structure in the spoil site; The specific process of assembling the bored cast-in-place rock-embedded pile foundation structure in the spoil site is as follows: 1) Select the size of the wire mesh, the length of the positioning steel bars and the size of the felt that are suitable for the diameter of the reinforcement cage in the specific project practice; 2) Install the wire mesh and tarpaulin between the two positioning steel bars, and design 2-4 rows along the direction of the pile body. Tie the positioning steel bars and the wire mesh tied to the tarpaulin with wire, with the distance between adjacent wires set to 20mm-50mm. After the three are tied together, apply asphalt on the tarpaulin. After the asphalt is applied on the tarpaulin, wrap the tarpaulin around the outer periphery of the steel cage that has been connected by welding. When wrapping, stirrups and hooks at the joints of the stirrups are set at intervals along the direction of the pile body on the wire mesh. The spacing between adjacent stirrups is 200mm-500mm, and the circumferential diameter of the stirrups should be set to be 20mm-50mm smaller than the diameter of the steel cage. Bend the upper end of the positioning steel bar into a hook shape so that it can be hung on the reserved steel casing to prevent it from falling and dislocating. 3) After completing steps 1) and 2), the steel cage and the asphalt-coated felt wrapped around it are hoisted; 4) After the steel cage is hoisted and fixed, the hook at the upper end of the positioning steel bar is hung on the steel casing to prevent it from falling or being dislocated. The concrete is transported into the pile hole using a conduit. During the transportation process, the concrete will shake up and down in the pile hole, which will automatically unhook the hook at the junction of the stirrups, allowing the wire mesh and tarpaulin to be laid neatly on the inner side of the retaining wall. 5) Continue the concrete delivery construction work. When the pouring is almost completed, the hook hanging on the steel casing should be clamped off or hammered straight and the reserved steel casing should be removed; 6) After the concrete pouring is completed, the bored cast-in-place rock-embedded pile foundation structure of the abandoned soil site will work normally. When the soil in the fill area around the pile foundation sinks, the asphalt coated on the felt and the wire mesh fixed around the pile foundation will play a role in reducing the negative friction resistance of the pile foundation.

2. The method for bored and cast-in-place rock-socketed pile foundation in spoil field according to claim 1, characterized in that: The diameter of the steel wire in the steel wire mesh (1) is set to 1mm-2mm, and the mesh diameter is set to 1mm-5mm; the binding wire is a steel wire with a diameter of 0.7mm-1.2mm and a length of 200mm-500mm.

3. The method for bored and cast-in-place rock-embedded pile foundation in spoil field according to claim 1, characterized in that: The tarpaulin (2) is configured as a tarpaulin structure with an asphalt layer coated on the surface, and the thickness of the asphalt layer is configured to be 5 mm to 10 mm.

4. The method for bored and cast-in-place rock-embedded pile foundation in spoil field according to claim 1, characterized in that: The diameter of the positioning steel bars (3) is set to 10 mm-20 mm, and the positioning steel bars (3) are provided with four arranged in an array along the circumference of the steel casing; the length of the hook is set to 20 mm-40 mm.

5. The method for bored and cast-in-place rock-socketed pile foundation in spoil field according to claim 1, characterized in that: The diameter of the stirrup is set to 6mm-12mm; the length of the hook is set to 20mm-30mm.

Images