Construction method of internally braced wedge-shaped blade steel pipe concrete pile

Abstract

This invention provides a construction method for a steel-concrete composite pile with internally supported wedge blades; including: Step 1, statically driving the perforated steel pipe (1) pile into the designed depth or predetermined position; wherein, during pile driving, wedge blades (2) are set inside the perforated steel pipe (1); Step 2, using an internal support device (3) to push out the wedge blades (2) inside the perforated steel pipe (1), then retracting the internal support device (3) and lowering it to the next set of wedge blades (2) for the push-out operation, repeating this operation; Step 3, retracting the internal support device (3): after all the wedge blades (2) have been pushed out, the internal support device (3) is pulled out of the pile body using a hoisting rope (8); Step 4, pouring fine stone concrete into the pile, and after the concrete hardens, the pile is ready. This invention is equipped with wedge blades (2), that is, the wedge blades (2) in the bearing layer can effectively expand the bearing area of ​​the pile body, significantly increasing the pile end resistance and pile side friction.

Description

Technical Field

[0001] This invention relates to the field of steel-concrete composite piles; and more particularly to a construction method for an internally braced wedge-shaped blade steel-concrete composite pile. Background Technology

[0002] my country has a vast territory and extremely complex engineering geological conditions, with a wide distribution of unfavorable geological formations such as deep soft soil, collapsible loess, and liquefiable sand. In these areas, deep foundation construction often requires conventional pile foundations with extremely long piles and large diameters to meet load-bearing requirements, significantly increasing project costs. Therefore, achieving "high load-bearing capacity, low settlement, and high reliability" for pile foundations under complex geological conditions has become a key scientific problem in geotechnical engineering. Current technologies still have the following shortcomings:

[0003] (1) Although traditional enlarged-base piles or spiral piles can increase the pile area, mechanical enlarged-base drill bits or propeller blades cause large disturbances and have high costs during construction.

[0004] (2) Existing recyclable expansion anchor technology: The expansion head set at the end of the anchor usually cannot be restored to its original state after grouting or mechanical expansion. Only the rod body can be recycled, and the anchor head remains in the soil.

[0005] (3) Existing methods for enlarging the diameter of steel pipe piles mostly rely on high-pressure grouting or bottom drilling, which usually cannot be used to enlarge the diameter within a specified soil layer according to changes in soil strata. For example, the gradually expanding fish-scale blade high-pressure grouting steel pipe pile expands the cross-section by high-pressure grouting inside the pile to open the "fish-scale" blades, but this method requires high-pressure grouting and a special blade structure. Another example is the sliding blade bottom-expanding pile, which is equipped with transverse sliding blades at the bottom of the pile. After sinking, the blades are squeezed open by the drill bit to expand the bottom surface, but this scheme is only limited to the expansion of the bottom of the pile.

[0006] The future development of pile foundation technology is showing three major trends: ① From single concrete piles or steel piles to "steel pipe-concrete" composite structures to fully utilize material properties. ② The elimination of high-pollution and high-noise processes, transitioning towards static pressure and micro-disturbance methods. ③ Actively regulating pile-soil interaction by changing the pile geometry (such as adding blades or bamboo joints), rather than passively relying on pile length. Existing research has fully demonstrated that "blade diameter expansion" is an effective way to improve bearing capacity, and "reasonable blade spacing" is key to design.

[0007] Therefore, there is an urgent engineering need to develop a new type of pile foundation that combines static pressure micro-disturbance construction with the high load-bearing capacity of blades. Against this backdrop, this invention proposes a technical method for expanding the diameter of a steel pipe pile by ejecting wedge-shaped blades through a recyclable internal support mechanism within the pile at a specified depth. Summary of the Invention

[0008] The purpose of this invention is to provide a construction method for internally supported wedge-shaped blade steel tube concrete piles.

[0009] This invention is achieved through the following technical solution:

[0010] This invention relates to a construction method for internally supported wedge-shaped blade steel-concrete composite piles, comprising the following:

[0011] Step 1: Static pressure driving of the perforated steel pipe 1 pile into the design depth or predetermined position; wherein, during pile driving, the wedge-shaped blade 2 is set inside the perforated steel pipe 1.

[0012] Step 2: The wedge-shaped blades 2 inside the perforated steel pipe 1 are pushed out by the internal support device 3. Then the internal support device 3 is retracted and the blades 2 are lowered to the next set for pushing out. This operation is repeated.

[0013] Step 3, retract the inner support device 3: After all the wedge blades 2 have been pushed out, pull the inner support device 3 out of the pile body using the hoisting rope 8;

[0014] Step 4: Pour fine stone concrete into the pile. After the concrete hardens, a composite pile structure of steel pipe-concrete-blade is formed.

[0015] Preferably, in step 1, the wedge-shaped blade 2 is integrally formed from the blade body 6 and the bottom plate 7 with V-groove; the bottom plate 7 with V-groove is configured in conjunction with the inner support device 3.

[0016] Once the blade body 6 extends beyond the pile and embeds itself in the surrounding soil, the V-groove bottom plate 7 is attached to the inner wall of the steel pipe 1, providing support for the blade 6 to withstand the force. Before the blade body 6 extends beyond the pile, during the descent of the internal support device 3, the V-groove bottom plate 7 provides a locking position for the internal support device 3, ensuring accurate positioning of the internal support device 3.

[0017] Preferably, in step 2, the internal support device 3 includes:

[0018] The suspension rope 8 is used to suspend the entire internal support device body inside the steel pipe pile, and includes power and data signal lines for transmitting the motor and infrared camera 11.

[0019] The motor is fixed to the mounting base at the lower end of the suspension rope 8, and its output end is connected to the gear set;

[0020] The gear set, connected to the lead screw drive, is used to amplify the rotational torque of the motor;

[0021] The lead screw is arranged vertically, and its upper end is connected to the gear set. When the lead screw rotates, it drives the support plates 5 on both sides to move in opposite directions or in opposite directions in the horizontal direction through the scissor linkage mechanism 9.

[0022] The support plate 5 is a symmetrically arranged two plate-shaped structure. The positioning spring 4 is set on its plate surface and is hinged to the middle rod of the scissor linkage mechanism 9. It slides horizontally as the lead screw rotates.

[0023] The positioning spring 4 is set on the support plate 5, and the inner support device 3 falls into the V-shaped flange of the bottom plate 7 with V-groove, which is used to align the support plate 5 with the middle of the blade body 6; during the inner support process, it will shrink and deform under the pressure of the inner wall of the steel pipe and the support plate 5.

[0024] The scissor linkage mechanism 9 is hinged to the support plate 5 in the middle, and the rotation of the lead screw causes the support plate 5 to move in the horizontal direction.

[0025] Infrared camera 11, fixed to the upper part of the mounting base, is used to collect infrared images of the target area and observe whether the wedge blade 2 is properly supported.

[0026] Preferably, in step 2, the specific process of the wedge-shaped blade 2 being ejected is as follows:

[0027] First, the inner support device 3 is suspended inside the perforated steel pipe 1 by the suspension rope 8, and then lowered to the wedge-shaped blade 2 that is to be pushed out.

[0028] Then, the positioning spring 4 locks the V-shaped flange with the V-groove bottom plate 7. During the descent, it drives the inner support device to rotate until the positioning spring 4 falls to the bottom of the V-shaped flange with the V-groove bottom plate 7. The support plate 5 is aligned with the middle of the blade body 6. The motor switch is turned on, and the screw with amplified torque through the gear set rotates. The scissor linkage mechanism 9 moves the support plate 5 toward the screw.

[0029] The support plate 5 pushes the wedge-shaped blade 2 to move out of the pile through the perforated steel pipe 1; the positioning spring 4 will shrink and deform under the pressure of the inner wall of the steel pipe and the support plate 5; after the wedge-shaped blade 2 is located at the designated hole 10, the blade body 6 extends out of the pile body through the hole 10, and the bottom plate 7 with V-groove is tightly attached to the inner wall of the steel pipe, and the internal support operation is completed.

[0030] Preferably, in step 3, the specific steps of retracting the inner support device 3 are as follows: after the wedge blade 2 is pushed out, the drive motor runs in the opposite direction to retract the support plate 5, the positioning spring 4 will be in a relaxed state again, and then the inner support device 3 will be pulled out of the pile body by the hoisting rope 8.

[0031] Preferably, after the support plate 5 presses against the bottom of the blade body 6, the motor is started to push the blade body 6 out of the pile. (The positioning spring 4 will press against the inner wall of the steel pipe and be compressed, so it will not get stuck between the bottom plate 7 with the V-groove and the inner wall of the steel pipe 1 with the hole). After the blade body 6 extends, it is embedded in the soil around the pile. This process is repeated to push all the wedge-shaped blades 2 out of the pile.

[0032] The present invention has the following advantages:

[0033] (1) Distributed wedge blade design: wedge blades are set at the specified soil layer position along the depth direction of the steel pipe pile, so that the diameter expansion effect is no longer limited to the pile end; in addition, during construction, after the straight steel pipe pile is inserted into the soil layer, the wedge blades are extended from the inside, which causes less disturbance to the original soil.

[0034] (2) Improve bearing capacity: The present invention is equipped with wedge-shaped blades, that is, the wedge-shaped blades in the bearing layer can effectively expand the bearing area of ​​the pile body, significantly increasing the pile end resistance and pile side friction.

[0035] (3) Precise positioning and selective diameter expansion: Based on the geological stratification, wedge-shaped blades are only ejected in soil layers with good bearing capacity and low compressibility, so as to minimize costs and achieve refined construction.

[0036] (4) Low-disturbance green construction: This invention adopts the static pile driving method, which is vibration-free and noise-free during construction. The blades are only deployed in the required bearing layer, which hardly disturbs other strata. No mud or impact tools are required, making it suitable for construction in sensitive places such as subways and building foundation pits.

[0037] (5) Equipment recycling: The internal support device is locked in the V-shaped flange of the wedge blade during the falling process by a specific locking key. The internal support device and the wedge blade work together to realize the positioning and ejection functions of the internal support device. After ejection, the internal support device can be retracted and pulled out from the pile, without being left in the soil. The internal support device can be recycled, reducing costs and realizing "accurate alignment, expansion and retraction" in the soil.

[0038] (6) Reliable and durable structure: After grouting, the steel pipe, concrete and blade form an integral force system. The inner and outer sides of the root of the wedge blade are subjected to soil pressure and concrete compressive stress, forming a firm anchor.

[0039] (7) Customizable: The number, size and spacing of wedge blades can be flexibly adjusted according to the bearing capacity of the strata to meet different geological conditions. Attached Figure Description

[0040] Figure 1 This is a structural diagram of a wedge-shaped blade;

[0041] Figure 2 This is a structural diagram of a steel pipe with holes;

[0042] Figure 3 This is a schematic diagram of the internal support device;

[0043] Figure 4 This is a top view of the steel pipe with holes after the wedge-shaped blades have been inserted.

[0044] Figure 5 This is a diagram demonstrating the positioning of the internal support device and the wedge-shaped blades;

[0045] Figure 6 This is a demonstration diagram of the ejection of the internal support device and the wedge-shaped blades;

[0046] Figure 7 This is a rendering of the finished product after the concrete pouring is completed;

[0047] Figure 8 This is a comparison chart of the performance of the steel pile of this invention with that of existing technologies;

[0048] The attached diagram is labeled as follows: 1 is a steel pipe with holes, 2 is a wedge-shaped blade, 3 is an internal support device, 4 is a positioning spring, 5 is a support plate, 6 is the blade body, 7 is a V-groove bottom plate, 8 is a lifting rope, 9 is a scissor linkage mechanism, 10 is a hole, and 11 is an infrared camera. Detailed Implementation

[0049] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are merely further illustrations of the present invention, but the scope of protection of the present invention is not limited to the following embodiments.

[0050] Example 1

[0051] This embodiment relates to a construction method for an internally supported wedge-shaped blade steel tube concrete pile, including the following:

[0052] Step 1: Static pressure drive the perforated steel pipe pile to the designed depth or predetermined position; see Figure 2 As shown, during pile driving, the wedge-shaped blade 2 is installed inside the perforated steel pipe 1; see Figure 4 As shown;

[0053] Step 2: The wedge-shaped blades 2 inside the perforated steel pipe 1 are pushed out by the internal support device 3. Then the internal support device 3 is retracted and the blades 2 are lowered to the next set for pushing out. This operation is repeated.

[0054] Step 3, retract the inner support device 3: After all the wedge blades 2 have been pushed out, pull the inner support device 3 out of the pile body using the hoisting rope 8;

[0055] Step 4: Pour fine aggregate concrete into the pile. After the concrete hardens, a composite pile structure of steel pipe-concrete-blade is formed. See... Figure 7 As shown.

[0056] Preferably, in step 1, the wedge-shaped blade 2 is integrally formed from a blade body 6 and a bottom plate 7 with a V-groove; the bottom plate 7 with a V-groove is configured to cooperate with the internal support device 3, see... Figure 1 As shown;

[0057] Once the blade body 6 extends beyond the pile and embeds itself in the surrounding soil, the V-groove bottom plate 7 is attached to the inner wall of the steel pipe 1, providing support for the stable bearing of the blade 6. Before the blade body 6 extends beyond the pile, during the descent of the internal support device, the V-groove bottom plate 7 provides a locking position for the internal support device 3, ensuring accurate positioning. (See...) Figure 5 As shown.

[0058] Preferably, in step 2, the internal support device 3 includes: (see...) Figure 3 As shown;

[0059] The suspension rope 8 is used to suspend the entire internal support device body inside the steel pipe pile, and includes power and data signal lines for transmitting the motor and infrared camera 11.

[0060] The motor is fixed to the mounting base at the lower end of the suspension rope 8, and its output end is connected to the gear set;

[0061] The gear set, connected to the lead screw drive, is used to amplify the rotational torque of the motor;

[0062] The lead screw is arranged vertically, and its upper end is connected to the gear set. When the lead screw rotates, it drives the support plates 5 on both sides to move in opposite directions or in opposite directions in the horizontal direction through the scissor linkage mechanism 9.

[0063] The support plate 5 is a symmetrically arranged two plate-shaped structure. The positioning spring 4 is set on its plate surface and is hinged to the middle rod of the scissor linkage mechanism 9. It slides horizontally as the lead screw rotates.

[0064] The positioning spring 4 is set on the support plate 5, and the inner support device 3 falls into the V-shaped flange of the bottom plate 7 with V-groove, which is used to align the support plate 5 with the middle of the blade body 6; during the inner support process, it will shrink and deform under the pressure of the inner wall of the steel pipe and the support plate 5.

[0065] The scissor linkage mechanism 9 is hinged to the support plate 5 in the middle, and the rotation of the lead screw causes the support plate 5 to move in the horizontal direction.

[0066] Infrared camera 11, fixed to the upper part of the mounting base, is used to collect infrared images of the target area and observe whether the wedge blade 2 is properly supported.

[0067] Preferably, in step 2, the specific process of the wedge-shaped blade 2 being ejected is as follows: see Figure 6 As shown;

[0068] First, the inner support device 3 is suspended inside the perforated steel pipe 1 by the suspension rope 8, and then lowered to the wedge-shaped blade 2 that is to be pushed out.

[0069] Then, the positioning spring 4 locks the V-shaped flange with the V-groove bottom plate 7. During the descent, it drives the inner support device to rotate until the positioning spring 4 falls to the bottom of the V-shaped flange with the V-groove bottom plate 7. The support plate 5 is aligned with the middle of the blade body 6. The motor switch is turned on, and the screw with amplified torque through the gear set rotates. The scissor linkage mechanism 9 moves the support plate 5 toward the screw.

[0070] The support plate 5 pushes the wedge-shaped blade 2 to move out of the pile through the perforated steel pipe 1; the positioning spring 4 will shrink and deform under the pressure of the inner wall of the steel pipe and the support plate 5; after the wedge-shaped blade 2 is located at the designated hole 10, the blade body 6 extends out of the pile body through the hole 10, and the bottom plate 7 with V-groove is tightly attached to the inner wall of the steel pipe, and the internal support operation is completed.

[0071] Preferably, in step 3, the specific steps of retracting the inner support device 3 are as follows: after the wedge blade 2 is pushed out, the drive motor runs in the opposite direction to retract the support plate 5, the positioning spring 4 will be in a relaxed state again, and then the inner support device 3 will be pulled out of the pile body by the hoisting rope 8.

[0072] Preferably, after the support plate 5 presses against the bottom of the blade body 6, the motor is started to push the blade body 6 out of the pile. (The positioning spring 4 will press against the inner wall of the steel pipe and be compressed, so it will not get stuck between the bottom plate 7 with the V-groove and the inner wall of the steel pipe 1 with the hole). After the blade body 6 extends, it is embedded in the soil around the pile. This process is repeated to push all the wedge-shaped blades 2 out of the pile.

[0073] Mechanical performance simulation

[0074] In ABAQUS software, a full-scale pile with a length of 10m was constructed for finite element simulation. Three sets of wedge-shaped blades were installed at the bottom of the pile. The pile body was modeled using hexahedral solid elements, and the soil was modeled using Mohr-Coulomb constitutive models, with all soil elements being hexahedral. The blades and soil were in "face-to-face contact".

[0075] Simulation results show that under vertical loads, the overall stress level of the internally supported wedge-shaped blade steel-concrete composite pile is significantly improved compared to that of a straight steel pile, making full use of the material properties of steel. Comparison of soil stress and displacement reveals that the internally supported wedge-shaped blade steel-concrete composite pile substantially alters the pile-soil interaction, allowing the upper load to be uniformly transferred to the surrounding soil.

[0076] By calculating the S-logP curve, it was found that under the same soil mesh division, the bearing capacity of the internally braced wedge-shaped steel pipe pile with three sets of blades was increased by approximately 35% compared to the straight pile of the same diameter. Figure 8 As shown.

[0077] The specific embodiments of the present invention have been described above. It should be understood that the present invention is not limited to the specific embodiments described above, and those skilled in the art can make various modifications or variations within the scope of the claims, which do not affect the essence of the present invention.

Claims

1. A construction method for an internally supported wedge-shaped blade steel-concrete composite pile, characterized in that, Including the following: Step 1: Static pressure is applied to drive the perforated steel pipe (1) pile into the designed depth or predetermined position; wherein, during pile driving, wedge-shaped blades (2) are installed inside the perforated steel pipe (1); Step 2: The wedge-shaped blades (2) inside the perforated steel pipe (1) are pushed out by the internal support device (3), and then the internal support device (3) is retracted and the blades (2) are lowered to the next set for pushing out. This operation is repeated. Step 3, retract the internal support device (3): After all the wedge blades (2) have been pushed out, pull the internal support device (3) out of the pile body using the hoisting rope (8); Step 4: Pour fine aggregate concrete into the pile. After the concrete hardens, a composite pile structure of steel pipe-concrete-blade is formed.

2. The construction method of the internally supported wedge-shaped blade steel tube concrete pile as described in claim 1, characterized in that, In step 1, the wedge blade (2) is integrally formed by the blade body (6) and the bottom plate with V-groove (7); the bottom plate with V-groove (7) is configured in conjunction with the inner support device (3).

3. The construction method of the internally supported wedge-shaped blade steel tube concrete pile as described in claim 1, characterized in that, In step 2, the internal support device (3) includes: The suspension rope (8) is used to suspend the entire internal support device body inside the steel pipe pile, and includes power and data signal lines for transmitting the motor and infrared camera (11); The motor is fixed to the mounting base at the lower end of the suspension rope (8), and its output end is connected to the gear set; Gear sets, connected to lead screw drives, are used to amplify the rotational torque of the motor; The lead screw is arranged vertically, and its upper end is connected to the gear set. When the lead screw rotates, it drives the support plates (5) on both sides to move in opposite directions in the horizontal direction through the scissor linkage mechanism (9). The support plate (5) is a symmetrically arranged two plate-shaped structure. The positioning spring (4) is set on its plate surface and is hinged to the middle rod of the scissor linkage mechanism (9). It slides horizontally as the lead screw rotates. The positioning spring (4) is set on the support plate (5), and the inner support device (3) falls into the V-shaped flange of the bottom plate (7) with V-groove, which is used to align the support plate (5) with the middle of the blade body (6); during the inner support process, it will shrink and deform under the pressure of the inner wall of the steel pipe and the support plate (5). The scissor linkage mechanism (9) is hinged in the middle to the support plate (5), and the rotation of the lead screw causes the support plate (5) to move in the horizontal direction; An infrared camera (11) is fixed to the upper part of the mounting base to collect infrared images of the target area and observe whether the wedge blade (2) is properly supported.

4. The construction method of the internally supported wedge-shaped blade steel tube concrete pile as described in claim 1, characterized in that, In step 2, the specific process of the wedge-shaped blade (2) being ejected is as follows: First, the inner support device (3) is suspended in the perforated steel pipe (1) by the suspension rope (8) and lowered to the wedge-shaped blade (2) to be pushed out; Then, the positioning spring (4) locks the V-shaped flange with the V-groove bottom plate (7). During the descent, it drives the inner support device to rotate until the positioning spring (4) falls to the bottom of the V-shaped flange with the V-groove bottom plate (7). The support plate (5) is aligned with the middle of the blade body (6). The motor switch is turned on, and the screw with amplified torque through the gear set rotates. The support plate (5) moves in the direction of the screw through the scissor linkage mechanism (9). The support plate (5) pushes against the wedge blade (2) and moves outward from the pile of the perforated steel pipe (1); the positioning spring (4) will shrink and deform under the pressure of the inner wall of the steel pipe and the support plate (5); the internal support operation is completed after the wedge blade (2) is located at the designated hole (10).

5. The construction method of the internally supported wedge-shaped blade steel tube concrete pile as described in claim 1, characterized in that, In step 3, the specific steps of retracting the inner support device (3) are as follows: after the wedge blade (2) is pushed out, the drive motor runs in the opposite direction to retract the support plate (5), the positioning spring (4) will be relaxed again, and then the inner support device (3) will be pulled out of the pile body by the hoisting rope (8).

6. The construction method of the internally supported wedge-shaped blade steel tube concrete pile as described in claim 4, characterized in that, After the support plate (5) presses against the bottom of the blade body (6), the motor is started to push the blade body (6) out of the pile.

Images