Precast pile stress detection system and reinforcement and deviation correction method

Abstract

The invention relates to the technical field of foundation piles, in particular to a precast pile stress detection system and a reinforcing and deviation rectifying method.The precast pile stress detection system comprises a plurality of pile bodies, every two vertically adjacent pile bodies are spliced, and each pile body comprises a reinforcement cage, a lower connecting flange, an upper connecting flange and a concrete pile body poured outside the reinforcement cage; the lower connecting flange is located at the head end of the concrete pile body, and the upper connecting flange is located at the tail end of the concrete pile body. A sleeve structure at a preset position is embedded into a reinforcement cage of the precast pile, reliable centering performance of an upper pile body and a lower pile body can be guaranteed through matching of a reinforcement and a hole in a flange, meanwhile, relative matching of the position of the sleeve structure is guaranteed, a complete and independent U-shaped channel is formed, a steel rope penetrates through the U-shaped channel, and the tensile stress of the steel rope is monitored by monitoring the change of the tensile stress data of the steel rope. The method can be used as a basis for judging whether the pile body is inclined or bent or not, early warning can be achieved, and reinforcing and deviation rectifying are conducted by additionally arranging the steel rope in the bending direction.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation piles, and particularly to a stress detection system for precast piles and a reinforcement and deviation correction method. Background Art

[0002] A precast pile is a foundation pile prefabricated in a factory or at a construction site, made of materials such as concrete, reinforced concrete, or steel. It is driven into the soil by a pile driving device to provide a stable foundation for a building, and has the characteristics of strong bearing capacity, high construction efficiency, and controllable quality.

[0003] Precast piles are usually spliced together to form a complete pile body. The upper and lower precast piles can be connected by welding, flange connection, or sulfur mortar anchor connection. When using welding or flange connection, if the connecting parts are uneven or have a large gap, it is easy for the upper and lower precast piles not to be on the same axis. When using sulfur mortar anchor connection, if the sulfur mortar ratio is improper and the temperature control is poor, the connection strength will be insufficient, and it is easy to crack or loosen during hammering, which will cause the pile body to tilt. At the same time, when the pile body is in contact with soft soil foundation, due to the low bearing capacity of the soil, it is also easy for the pile body to deform or tilt due to eccentric loading.

[0004] The pile body deflection caused by the above construction or geological conditions is generally not easy to be detected early, and the later deviation correction of the pile body usually can only be carried out by methods such as straightening with a ground anchor, reverse excavation, or adding piles. The deviation correction construction is difficult and the effect is limited. Therefore, how to early warn of the bending and deviation of the pile body in advance is an urgent problem to be solved. Summary of the Invention

[0005] In view of the technical problems existing in precast piles in the prior art, the first aspect of the present invention provides a stress detection system for precast piles, including:

[0006] A plurality of pile bodies, the upper and lower adjacent pile bodies are spliced with each other. The pile body includes a steel reinforcement cage, a lower connection flange, an upper connection flange, and a concrete pile body cast outside the steel reinforcement cage. The lower connection flange is located at the head end of the concrete pile body, and the upper connection flange is located at the tail end of the concrete pile body;

[0007] A pile tip, connected to the bottom of the lowermost pile body. The pile tip includes a concrete pile head, a pile tip connection flange, a steel core, and a plurality of U-shaped sleeves. The concrete pile head is configured with a conical structure at the bottom, the steel core is embedded in the concrete pile head, and the pile tip connection flange is located at the upper end of the concrete pile head;

[0008] At least two steel ropes, the first end of each steel rope penetrates into the uppermost pile body, bypasses the pile tip, and then penetrates out of the uppermost pile body. The free end of the steel rope is fixed by the stress monitoring device of the pile body;

[0009] A controller for receiving stress monitoring information sent by all stress monitoring devices;

[0010] Wherein, the steel reinforcement cage includes a steel bar structure and a casing structure, and the lower connecting flange and the upper connecting flange are provided with docking holes corresponding to the distribution of the steel bar structure and the casing structure, and the casing structure is connected to the lower connecting flange and the upper connecting flange;

[0011] When the upper and lower pile bodies are docked, the steel bar structure is inserted into the docking hole of the upper connecting flange, so that the positions of the casing structures in the upper and lower pile bodies correspond, and both ends of each U-shaped casing correspond to the two casing structures in the radial section of the precast pile;

[0012] Wherein, the stress monitoring device is used to pull the two free ends of each steel wire rope and periodically monitor the tensile stress received by the steel wire rope.

[0013] Preferably, the steel bar structure includes an inner layer of steel bars, an intermediate layer of steel bars and an outer layer of steel bars. The intermediate layer of steel bars is a spiral steel bar, and the inner layer of steel bars and the outer layer of steel bars are linear steel bars welded to the inner wall and the outer wall of the spiral steel bar. The spiral steel bar is between the lower connecting flange and the upper connecting flange.

[0014] Preferably, the casing structure is arranged on the inner layer and / or the outer layer of the spiral steel bar.

[0015] Preferably, the casing structure is centrosymmetrically distributed around the axis of the precast pile, and the casing structure and the linear steel bars are alternately distributed in the same circumferential direction.

[0016] Preferably, the upper connecting flange includes a cover body and a connecting plate. The cover body and the connecting plate are connected by a connecting ring. An installation gap is formed between the outer side of the connecting ring, the cover body and the connecting plate, and the linear steel bar extends into the installation gap.

[0017] Preferably, the adjacent two pile bodies are connected by bolts or welding.

[0018] Preferably, the docking hole includes a first docking hole and a second docking hole. The diameter and position of the first docking hole correspond to the linear steel bar, and the diameter and position of the second docking hole correspond to the casing structure. The number of the second docking holes and the casing structures is an even number greater than 4.

[0019] Preferably, the two free ends of the first steel wire rope are respectively connected to a first stress monitoring device and a second stress monitoring device, and the two free ends of the second steel wire rope are respectively connected to a third stress monitoring device and a fourth stress monitoring device. Among them, the planes where the first steel wire rope and the second steel wire rope are located are perpendicular to each other.

[0020] In a second aspect of the present invention, a technical solution is proposed, a method for reinforcing and rectifying a precast pile, using the above-mentioned stress detection system for precast piles, characterized by comprising the following steps:

[0021] Step 1: Number each stress monitoring device, determine the positions of the stress monitoring devices with different numbers, and periodically obtain the stress data of the steel ropes monitored by all stress monitoring devices;

[0022] Step 2: Determine whether each stress monitoring device exceeds a preset value, mark the numbers of the stress monitoring devices that exceed the preset value, and generate an alarm;

[0023] Step 3: Determine the deflection direction of the precast pile according to the position of the marked stress monitoring device in the circumferential direction of the precast pile;

[0024] Step 4: Add steel ropes to the casing structures on both sides of the marked stress monitoring device, install new stress monitoring devices at both ends, and control the stress of the steel ropes within the preset range to achieve reinforcement and rectification.

[0025] Preferably, the stress monitoring device is configured to be able to change the tensile stress of the steel rope by electric or manual means. When the stress monitoring device is marked, control the stress monitoring device to increase the tensile stress of the steel rope.

[0026] Compared with the prior art, the advantages of the present invention are as follows:

[0027] In this application, a casing structure is embedded in the reinforcement cage of the precast pile, and flanges are provided at both the upper and lower ends of the precast pile. When the upper and lower pile bodies are connected to each other during the pressing process, reliable centering of the upper and lower pile bodies can be ensured through the cooperation of the steel bars and the holes in the flanges. At the same time, the positions of the casing structures are also ensured to be relatively matched to form a complete and independent U-shaped channel. The steel rope passes through the U-shaped channel, and the two free ends of the steel rope are fixed to the top of the pile body through stress monitoring devices, so that a slightly tight pressing state is formed between each section of the precast pile, which can improve the strength of the pile body. At the same time, by monitoring the change of the tensile stress data of the steel rope, it can be used as a basis for judging whether the pile body is inclined or bent, and early warning can be realized, and reinforcement and rectification can be carried out by adding steel ropes in the bending direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The drawings are not intended to be drawn to scale. In the drawings, each identical or approximately identical component shown in each figure may be represented by the same reference numeral. For the sake of clarity, not every component is labeled in each figure. Now, embodiments of various aspects of the present invention will be described by way of example and with reference to the drawings, wherein:

[0029] Figure 1It is a schematic structural diagram of the stress detection system for precast piles shown in the present invention;

[0030] Figure 2 It is a schematic structural diagram of the pile body shown in the present invention;

[0031] Figure 3 It is a schematic structural diagram of the steel bar core shown in the present invention;

[0032] Figure 4 It is a schematic diagram of the connection state of the upper and lower pile bodies shown in the present invention;

[0033] Figure 5 It is a top view of the upper connecting flange shown in the present invention;

[0034] Figure 6 It is a schematic diagram of the steel rope penetrating into the pile body and the pile tip shown in the present invention;

[0035] Figure 7 It is a top view of multiple stress monitoring devices at the upper end of the pile body shown in the present invention. Specific Embodiments

[0036] To better understand the technical content of the present invention, specific embodiments are hereby given and described in conjunction with the accompanying drawings as follows.

[0037] Combined with Figure 1 As shown, a first aspect of the present invention provides a stress detection system for precast piles, including a plurality of pile bodies 100, pile tips 200, and at least two steel ropes 300.

[0038] Two adjacent pile bodies 100 are spliced together, and the pile tip 200 is connected to the lower end of the lowermost pile body 100. During the pile pressing construction of the precast pile, the pile tip 200 is first connected to the lowermost pile body 100, and then a pile pressing device is used to press the pile body 100. Through the extrusion effect of the pile tip 200 on the soil layer, the pile body 100 is driven to a predetermined depth by the downward pressure.

[0039] The first end of each steel rope penetrates into the uppermost pile body 100, bypasses the pile tip 200, and then penetrates out of the uppermost pile body 100. The free end of the steel rope 300 is fixed by the stress monitoring device 400 of the pile body 100.

[0040] In this way, the steel rope 300 can keep all the pile bodies 100 in a compressed state. Since the compressive performance of the concrete structure is much higher than the tensile performance, the pre-pressure applied by the steel rope 300 is beneficial to keeping the multiple pile bodies 100 in a slightly compressed state with each other, ensuring the stability of the pile bodies.

[0041] At the same time, by monitoring the tensile stress of the steel rope 300 through the stress monitoring device 400, when multiple pile bodies 100 are tilted or bent due to external stress, the tensile stress of the steel rope 300 will produce a large change in the bending direction. Therefore, by monitoring the tensile stress of the steel rope 300, an early warning can be issued for the status of the pile body 100.

[0042] Combination Figure 1 As shown, the pile tip 200 is connected to the bottom of the lowest pile body 100, and the pile tip 200 includes a concrete pile head 210, a pile tip connecting flange 220, a steel core 230 and a plurality of U-shaped sleeves 240. The concrete pile head 210 is constructed with a conical structure at the bottom, the steel core 230 is embedded in the concrete pile head 210, and the pile tip connecting flange 220 is located at the upper end of the concrete pile head 210.

[0043] Specifically, the steel core 230 is constructed with a plurality of steel bars distributed in a cone shape at the bottom, and a U-shaped steel cage with an upward opening formed at the top. This steel core 230 structure can effectively ensure the strength below the pile tip 200, while also preventing stress from being transmitted in the direction of the U-shaped sleeve 240, thereby preventing the area where the U-shaped sleeve 240 is located from being squeezed and deformed, thereby preventing the U-shaped sleeve 240 from being damaged.

[0044] It should be understood that since the steel rope 300 needs to penetrate downward from the top, then bend upward through the U-shaped sleeve 240 in the pile tip 200 and pass out from the other side, ensuring that the U-shaped sleeve 240 is not damaged is a necessary condition for the steel rope 300 to penetrate.

[0045] Furthermore, in order to improve the strength of the pile body 100, Figure 2 As shown, the pile body 100 includes a steel cage 110 , a lower connecting flange 120 , an upper connecting flange 130 and a concrete pile body 101 cast outside the steel cage 110 . The lower connecting flange 120 is located at the head end 102 of the concrete pile body 101 , and the upper connecting flange 130 is located at the tail end 103 of the concrete pile body 101 .

[0046] In this way, the steel cage 110 and the lower connecting flange 120 and the upper connecting flange 130 are welded and connected to form the skeleton of the pile body 100 , and the concrete pile body 101 is poured outside the steel cage 110 to form a high-strength pile body 100 .

[0047] Among them, the steel cage 110 includes a steel structure and a sleeve structure 112, and the lower connecting flange 120 and the upper connecting flange 130 are provided with docking holes 134 distributed corresponding to the steel structure and the sleeve structure 112, and the sleeve structure 112 is connected to the lower connecting flange 120 and the upper connecting flange 130.

[0048] It can be understood that the casing structure 112 and the U-shaped casing 240 form a channel for the steel rope 300 to pass through. Therefore, the positions of the casing structures 112 in multiple pile bodies 100 correspond to each other. Only after docking can a complete channel be ensured to prevent the steel rope 300 from being unable to penetrate downward from the upper end of the pile body to the pile tip 200 and then return to the upper end of the pile body.

[0049] When the upper and lower pile bodies 100 are docked, the steel bar structure is arranged to be inserted into the docking hole 134 of the upper connection flange 130, so that the positions of the casing structures 112 in the upper and lower pile bodies 100 correspond to each other. The two ends of each U-shaped casing 240 correspond to the positions of the two casing structures 112 in the radial section of the precast pile.

[0050] Among them, each U-shaped casing 240 is relatively independent.

[0051] In this way, when all the pile bodies 100 are connected to each other during the process of being pressed into the soil layer, the casing structure 112 and the U-shaped casing 240 in the formed pile body can form a complete U-shaped channel, and the steel rope 300 can penetrate from one end of the U-shaped channel and exit from the other end.

[0052] Combined with Figure 3 As shown, the steel bar structure includes an inner layer steel bar, an intermediate layer steel bar, and an outer layer steel bar. The intermediate layer steel bar is a spiral steel bar 113, and the inner layer steel bar and the outer layer steel bar are linear steel bars 111 welded to the inner wall and the outer wall of the spiral steel bar 113. The spiral steel bar 113 is located between the lower connection flange 120 and the upper connection flange 130.

[0053] In this way, through the steel bar structure set with this three-layer structure, it is beneficial to ensure that the pile body has a high bearing capacity.

[0054] Optionally, the casing structure 112 is arranged on the inner layer and / or the outer layer of the spiral steel bar 113. The casing structure 112 is centrosymmetrically distributed around the axis of the precast pile, and the casing structure 112 and the linear steel bar 111 are alternately distributed in the same circumferential direction.

[0055] In this way, the setting of the casing structure 112 can cover multiple angles in the circumferential direction of the pile body, which is beneficial to strengthening the deflection direction according to the state of the pile body.

[0056] In an alternative embodiment, the casing structure 112 and the U-shaped casing 240 have the same diameter. The casing structure 112 and the U-shaped casing 240 can adopt a plastic pipe structure. Before pouring concrete, they are tied to the predetermined positions of the steel reinforcement cage 110 or the steel bar core 230 with steel wires to ensure their proper positions.

[0057] In an alternative embodiment, the diameters of the casing structure 112 and the U-shaped casing 240 are approximately 1.5 to 2 times the diameter of the steel cable 300, which is conducive to the smooth passage of the steel cable 300 in the U-shaped channel. Optionally, the diameter of the steel cable 300 is greater than 8 mm.

[0058] Among them, the stress monitoring device 400 is used to pull the two free ends of each steel cable 300 and periodically monitor the tensile stress applied to the steel cable 300.

[0059] Combined with Figure 6 As shown, the stress monitoring device 400 includes a support base 410, a steel cable locking structure 420, and a pressure monitoring component 430. The pressure monitoring component 430 is disposed between the support base 410 and the steel cable locking structure 420. The steel wire locking structure 420 includes a locking portion and a connecting portion. The locking portion is used to lock the steel cable 300. The support base 410 is fixed to the upper connecting flange 130. The distance between the connecting portion and the support base 410 can be adjusted through a threaded or linear drive structure. Therefore, when the distance between the connecting portion and the support base 410 increases, the pre-tightening force of the steel cable 300 can be increased, and the pre-tightening force of the steel cable 300 at this time can be monitored through the pressure monitoring component 430.

[0060] Optionally, the stress monitoring device 400 is connected to a controller. The controller is used to receive the stress monitoring information sent by all the stress monitoring devices 400. The controller and the stress monitoring device 400 can complete the information transmission through wired or wireless means.

[0061] After the controller receives the stress data of the steel cable 300 monitored by the stress monitoring device 400, it can be compared with the prestress range of the steel cable 300 to determine whether the current stress state of the steel cable 300 is normal.

[0062] Combined with Figure 4 and Figure 5 As shown, the upper connecting flange 130 includes a cover body 131 and a connecting plate 132. The cover body 131 and the connecting plate 132 are connected through a connecting ring 135. An installation gap 133 is formed between the outer side of the connecting ring 135, the cover body 131, and the connecting plate 132. The linear steel bar 111 extends into the installation gap 133.

[0063] Optionally, the cover body 131 covers the head end 102 of the concrete pile body 101, which can increase the strength of the head end 102 of the pile body 101 to avoid damage caused by being struck by the pile pressing equipment.

[0064] The outer contour of the above-mentioned upper connecting flange 130 is the same as the outer diameter of the pile body, and the top is flat, which is conducive to the pile body being pressed in and also ensures the structural strength when being struck by the pile pressing equipment.

[0065] Thus, when the upper and lower pile bodies 100 are connected, the linear steel bars 111 in the upper pile body 100 can extend into the installation gap 133. The end portions of the linear steel bars 111 are configured to have threads. By installing nuts in the areas where the linear steel bars 111 are exposed in the installation gap 133, the upper and lower pile bodies 100 are connected and locked.

[0066] It should be understood that the above method of inserting the linear steel bars 111 into the docking holes 134 and extending them into the installation gap 133 can ensure that the upper and lower pile bodies 100 can be aligned, ensuring better coaxiality. Therefore, when being pressed in, the pile body can be prevented from tilting or being non-coaxial.

[0067] In an alternative embodiment, after the linear steel bars 111 extend into the installation gap 133, they can also be connected and fixed to the connecting plate 132 by welding.

[0068] Combined with Figure 7 As shown, the docking holes 134 include a first docking hole 134a and a second docking hole 134b. The diameter and position of the first docking hole 134a correspond to the linear steel bars 111, and the diameter and position of the second docking hole 134b correspond to the sleeve structures 112. The number of the second docking holes 134b and the sleeve structures 112 is an even number greater than 4.

[0069] Specifically, the diameter of the first docking hole 134a is the same as the diameter of the linear steel bars 111, and the second docking hole 134b is the same as the outer diameter of the sleeve structures 112.

[0070] Furthermore, the length of the sleeve structures 112 is set to extend to half of the depth of the second docking hole 134b. Thus, when the upper and lower pile bodies are docked, the sleeve structures 112 are docked and form a seal. After inserting the steel ropes 300 into the corresponding sleeve structures 112, anti-corrosion can be achieved by pouring oil into the sleeve structures 112, so as to prevent the stress on the steel ropes 300 from changing greatly due to corrosion.

[0071] Combined with Figure 6 and Figure 7 As shown, the two free ends of the first steel rope are respectively connected to the first stress monitoring device 401 and the second stress monitoring device 402, and the two free ends of the second steel rope are respectively connected to the third stress monitoring device 403 and the fourth stress monitoring device 404. Among them, the planes where the first steel rope and the second steel rope are located are perpendicular to each other.

[0072] Thus, by periodically collecting (e.g., with a collection frequency of once a day) the stress data monitored by the first stress monitoring device 401 and the second stress monitoring device 402, it is possible to timely detect whether the stress on the plane (plane A-A) where the first steel rope is located changes. And by periodically collecting the stress data monitored by the third stress monitoring device 403 and the fourth stress monitoring device 404, it is possible to timely detect whether the stress on the plane (plane B-B) where the second steel rope is located changes.

[0073] When the stress on the A-A plane increases, it indicates that the pile body may tilt or bend in a direction parallel to the A-A plane. By threading steel ropes into the casing structures 112 on both sides of the first steel rope, the strength of the pile body in the direction of the A-A plane is increased.

[0074]

Reinforcement and deviation correction method for precast piles

[0075] A technical solution is proposed in the second aspect of the present invention. A reinforcement and deviation correction method for precast piles, using the above-mentioned stress detection system for precast piles, is characterized by including the following steps:

[0076] Step 1: Number each stress monitoring device 400, determine the positions where the stress monitoring devices 400 with different numbers are located, and periodically obtain the stress data of the steel ropes 300 monitored by all stress monitoring devices 400.

[0077] Step 2: Judge whether each stress monitoring device 400 exceeds a preset value, mark the numbers of the stress monitoring devices 400 that exceed the preset value, and generate an alarm.

[0078] Step 3: According to the positions of the marked stress monitoring devices 400 in the circumferential direction of the precast pile, judge the deviation direction of the precast pile in this direction.

[0079] Step 4: Add steel ropes 300 to the casing structures 112 on both sides of the marked stress monitoring devices 400, install new stress monitoring devices 400 at both ends, and control the stress of the steel ropes 300 within the preset range to achieve reinforcement and deviation correction.

[0080] Combined with Figure 7 As shown, the two free ends of the first steel rope are respectively connected to the first stress monitoring device 401 (number 1) and the second stress monitoring device 402 (number 2), and the two free ends of the second steel rope are respectively connected to the third stress monitoring device 403 (number 3) and the fourth stress monitoring device 404 (number 4). Among them, the planes where the first steel rope and the second steel rope are located are perpendicular to each other.

[0081] Periodically collect the stress data monitored by the first stress monitoring device 401 and the second stress monitoring device 402, and it can promptly detect whether the stress on the plane (plane A-A) where the first steel rope is located changes. By periodically collecting the stress data monitored by the third stress monitoring device 403 and the fourth stress monitoring device 404, it can promptly detect whether the stress on the plane (plane B-B) where the second steel rope is located changes.

[0082] If No. 1 and No. 2 are marked, it indicates that the stress on the A-A plane increases, and the pile body may tilt or bend along the direction parallel to the A-A plane. Steel ropes can be inserted into the casing structures 112 on both sides of the first steel rope to increase the strength of the pile body in the A-A plane direction.

[0083] In an alternative embodiment, the stress monitoring device 400 is configured to be able to change the magnitude of the tensile stress on the steel rope 300 electrically or manually. After the stress monitoring device 400 is marked, control the stress monitoring device 400 to increase the tensile stress on the steel rope 300. In this way, the tensile force of the steel rope 300 can be increased on the basis of the original tensile stress, and the strength of the pile body in the direction of this steel rope 300 can be increased.

[0084] Combining the above embodiments, in the present application, the casing structure is embedded in the steel reinforcement cage of the precast pile at a predetermined position, and flanges are provided at both the upper and lower ends of the precast pile. When the upper and lower pile bodies are connected to each other during the pressing process, the reliable centering of the upper and lower pile bodies can be ensured through the cooperation of the steel bars and the holes in the flanges. At the same time, the relative positions of the casing structures are also ensured to be matched to form a complete and independent U-shaped channel. The steel rope is passed through the U-shaped channel, and the two free ends of the steel rope are fixed to the top of the pile body through the stress monitoring device, so that a slightly tight pressing state is formed between each precast pile, which can improve the strength of the pile body. At the same time, by monitoring the change of the tensile stress data of the steel rope, it can be used as a basis for judging whether the pile body is tilted or bent, and early warning can be realized, and reinforcement and deviation correction can be carried out by adding steel ropes in the bending direction.

[0085] Although the present invention has been disclosed above with preferred embodiments, it is not intended to limit the present invention. Those with ordinary knowledge in the technical field to which the present invention pertains can make various modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the protection scope of the present invention shall be determined by what is defined in the claims.

Claims

1. A stress detection system for prefabricated piles, characterized in that: include: A plurality of pile bodies (100), wherein two upper and lower adjacent pile bodies (100) are spliced ​​together, wherein the pile body (100) comprises a steel cage (110), a lower connecting flange (120), an upper connecting flange (130), and a concrete pile body (101) cast outside the steel cage (110), wherein the lower connecting flange (120) is located at the head end (102) of the concrete pile body (101), and the upper connecting flange (130) is located at the tail end (103) of the concrete pile body (101); A pile tip (200) is connected to the bottom of the pile body (100) at the bottom, the pile tip (200) comprising a concrete pile head (210), a pile tip connection flange (220), a steel core (230) and a plurality of U-shaped sleeves (240), the concrete pile head (210) being constructed with a conical structure at the bottom, the steel core (230) being embedded in the concrete pile head (210), and the pile tip connection flange (220) being located at the upper end of the concrete pile head (210); At least two steel ropes (300), the first end of each steel rope passes through the uppermost pile body (100), passes around the pile tip (200) and then passes out of the uppermost pile body (100), and the free end of the steel rope (300) is fixed by a stress monitoring device (400) connected to the pile body (100); The steel cage (110) comprises a steel structure and a sleeve structure (112); the lower connecting flange (120) and the upper connecting flange (130) are provided with docking holes (134) distributed corresponding to the steel structure and the sleeve structure (112); the sleeve structure (112) is connected to the lower connecting flange (120) and the upper connecting flange (130); When the upper and lower pile bodies (100) are butt-jointed, the steel bar structure is inserted into the butt-jointed hole (134) of the upper connecting flange (130), so that the positions of the sleeve structures (112) in the upper and lower pile bodies (100) correspond, and the two ends of each U-shaped sleeve (240) correspond to the positions of the two sleeve structures (112) located on the radial section of the precast pile; The stress monitoring device (400) is used to pull the two free ends of each steel rope (300) and periodically monitor the tensile stress exerted on the steel rope (300).

2. The stress detection system for precast piles according to claim 1, characterized in that: The steel bar structure comprises an inner layer of steel bars, an intermediate layer of steel bars and an outer layer of steel bars, wherein the intermediate layer of steel bars is a spiral steel bar (113), and the inner layer of steel bars and the outer layer of steel bars are linear steel bars (111) welded to the inner wall and the outer wall of the spiral steel bar (113), and the spiral steel bar (113) is located between a lower connecting flange (120) and an upper connecting flange (130).

3. The stress detection system for precast piles according to claim 2, characterized in that: The sleeve structure (112) is arranged on the inner layer and / or outer layer of the spiral steel bar (113).

4. The stress detection system for precast piles according to claim 1, characterized in that: The sleeve structures (112) are distributed in a centrally symmetrical manner around the axis of the precast pile, and the sleeve structures (112) and the linear steel bars (111) are distributed alternately in the same circumferential direction.

5. The stress detection system for precast piles according to claim 4, characterized in that: The upper connecting flange (130) comprises a cover body (131) and a connecting plate (132); the cover body (131) and the connecting plate (132) are connected via a connecting ring (135); an installation gap (133) is formed between the outer side of the connecting ring (135), the cover body (131) and the connecting plate (132); and the linear steel bar (111) extends into the installation gap (133).

6. The stress detection system for precast piles according to claim 5, characterized in that: Two adjacent pile bodies (100) are connected by bolts or welding.

7. The stress detection system for precast piles according to claim 5, characterized in that: The docking hole (134) includes a first docking hole (134a) and a second docking hole (134b), the diameter and position of the first docking hole (134a) correspond to the linear steel bar (111), the diameter and position of the second docking hole (134b) correspond to the sleeve structure (112), and the number of the second docking hole (134b) and the sleeve structure (112) is an even number greater than 4.

8. The stress detection system for precast piles according to claim 1, characterized in that: The two free ends of the first steel rope are respectively connected to the first stress monitoring device (401) and the second stress monitoring device (402), and the two free ends of the second steel rope are respectively connected to the third stress monitoring device (403) and the fourth stress monitoring device (404), wherein the planes in which the first steel rope and the second steel rope are located are perpendicular to each other.

9. A method for reinforcing and correcting precast piles, using the precast pile stress detection system according to any one of claims 1 to 8, characterized in that: The following steps are involved: Step 1, numbering each stress monitoring device (400), determining the location of stress monitoring devices (400) with different numbers, and periodically acquiring stress data of the steel rope (300) monitored by all stress monitoring devices (400); Step 2: determining whether each stress monitoring device (400) exceeds a preset value, marking the number of the stress monitoring device (400) that exceeds the preset value, and generating an early warning; Step 3: according to the position of the marked stress monitoring device (400) in the circumferential direction of the precast pile, determine that the direction is the deflection direction of the precast pile; Step 4: Add steel ropes (300) to the casing structure (112) on both sides of the marked stress monitoring device (400), and install new stress monitoring devices (400) at both ends to control the stress of the steel rope (300) within a preset range to achieve reinforcement and deviation correction.

10. The method for reinforcing and correcting the deviation of prefabricated piles according to claim 9, characterized in that: The stress monitoring device (400) is configured to change the magnitude of the tensile stress on the steel rope (300) by electric or manual means. When the stress monitoring device (400) is marked, the stress monitoring device (400) is controlled to increase the tensile stress on the steel rope (300).

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