Force conversion device, precast pile structure with force conversion device and construction method

Abstract

The invention discloses a force conversion device, a precast pile structure with the force conversion device and a construction method. The force conversion device comprises an outer side interlayer stiffening pipe, an inner side interlayer stiffening pipe and a flexible communicating vessel. The outer side interlayer stiffening pipe is arranged on the periphery of the inner side interlayer stiffening pipe in a sleeving mode, and the bottom of the inner side interlayer stiffening pipe and the bottom of the outer side interlayer stiffening pipe are connected with the flexible communicating vessels. The invention discloses a precast pile structure with a force conversion device. The force conversion device is sleeved on the outer side wall of a formed precast pile. A construction method of the precast pile structure with the force conversion device comprises the steps that construction of a standard precast pile section is completed firstly, and then alternate construction of the precast pile section where a negative friction soil layer is located and the force conversion device is conducted; or construction of all the precast pile sections is completed firstly, and then construction of the precast pile section force conversion device where the negative friction resistance soil layer is located is completed. The device has the beneficial effects that the negative frictional resistance of the soil layer borne by the pile side of the precast pile is converted through a specific device, and the adverse negative frictional resistance is converted into positive frictional resistance.

Description

Technical Field

[0001] The present invention relates to the field of pile foundations, and in particular to a force conversion device, a precast pile structure with the device, and a construction method thereof. Background Art

[0002] Negative skin friction is the downward frictional force generated when the settlement of the soil around the pile is greater than the settlement of the pile body. It is common in areas such as soft soil and loess areas and is extremely harmful: 1. The force on the pile body deteriorates; 2. It leads to structural safety risks.

[0003] In response to the above negative skin friction problem, there are currently several solutions in engineering: 1. Design refinement. Deepen the pile length so that the pile tip penetrates into a stable stratum. 2. Material and structural measures. Coat anti-friction coatings such as asphalt and polyethylene on the pile side; set isolation sleeves such as steel or PVC sleeves in the soil layer prone to settlement to cut off the transmission of negative skin friction. 3. Foundation treatment.

[0004] The above solution 1 for pile side negative skin friction increases the engineering investment, but the pile side negative skin friction remains unchanged; the additional anti-friction measures in solution 2 reduce the pile side negative skin friction, but it has not been reduced to zero yet; solution 3 improves or changes the soil layer causing negative skin friction, and the pile side negative skin friction depends on the specific foundation treatment measures. The actual engineering geological conditions vary greatly and cannot be completely solved by this method, and its cost is huge. Summary of the Invention

[0005] The purpose of the present invention is: a force conversion device, a precast pile structure with the device, and a construction method thereof, which convert the adverse effect (negative skin friction) of the soil layer on the side of the concrete precast pile through a specific device, so that the adverse effect is converted into a favorable effect (positive skin friction).

[0006] The present invention is realized through the following technical solutions: a force conversion device includes an outer sandwich stiffening pipe, an inner sandwich stiffening pipe, and a flexible connector; wherein the inner sandwich stiffening pipe is sleeved on the outer wall surface of the pile structure and fixedly connected to the pile structure; the outer sandwich stiffening pipe is sleeved on the outer periphery of the inner sandwich stiffening pipe, and a flexible connector for connecting the inner cavities of the inner sandwich stiffening pipe and the outer sandwich stiffening pipe is connected to the bottom of the inner sandwich stiffening pipe and the outer sandwich stiffening pipe. A liquid is provided in the inner sandwich stiffening pipe, the outer sandwich stiffening pipe, and the flexible connector, and the tops of the inner sandwich stiffening pipe and the outer sandwich stiffening pipe are both blocked;

[0007] Both the outer sandwich stiffening pipe and the inner sandwich stiffening pipe include an outer pipe body and an inner pipe body. The outer pipe body is sleeved on the outer periphery of the inner pipe body, and there is a gap between the inner pipe body and the outer pipe body. The outer pipe body and the inner pipe body are connected by a plurality of vertically distributed stiffening plates; a plurality of wing plates are provided on the outer wall surface of the outer sandwich stiffening pipe and are distributed from top to bottom and extend outward.

[0008] A precast pile structure with a force conversion device, the main body being several precast pile segments, and pile end steel hoops being provided at the ends of the precast pile segments. Among them, the precast pile segments are divided into standard precast pile segments and precast pile segments for negative skin friction according to their different position functions;

[0009] A force conversion device is sleeved on the outer side wall of the precast pile segment for negative skin friction; the force conversion device mainly includes an outer sandwich stiffening tube, an inner sandwich stiffening tube, and a flexible connector; among them, the inner sandwich stiffening tube is sleeved on the outer side wall of the precast pile segment for negative skin friction and fixedly connected to the precast pile segment for negative skin friction; the outer sandwich stiffening tube is sleeved on the outer periphery of the inner sandwich stiffening tube, and a flexible connector for communicating the inner cavities of the outer sandwich stiffening tube and the inner sandwich stiffening tube is connected at the bottom of the inner sandwich stiffening tube and the outer sandwich stiffening tube. A liquid is provided in the inner sandwich stiffening tube, the outer sandwich stiffening tube, and the flexible connector, and the tops of the inner sandwich stiffening tube and the outer sandwich stiffening tube are both blocked;

[0010] Both the outer sandwich stiffening tube and the inner sandwich stiffening tube include an outer tube body and an inner tube body. The outer tube body is sleeved on the outer periphery of the inner tube body, and there is a gap between the inner tube body and the outer tube body. The outer tube body and the inner tube body are connected by several vertically distributed stiffening plates;

[0011] A plurality of wing plates are provided on the outer side wall of the outer sandwich stiffening tube, which are distributed from top to bottom and extend outward.

[0012] A construction method for a precast pile structure with a force conversion device is characterized by including the following steps:

[0013] Step 1: Determine the total thickness of the soil layer with negative skin friction at the pile forming point according to the geological exploration data, and prepare the precast pile segments for negative skin friction that need to install the force conversion device. The precast pile segments for negative skin friction are single or multiple and are connected in sequence, and the total length of the precast pile segments for negative skin friction is slightly longer than the distance from the lower end of the negative skin friction soil layer to the bottom of the bearing platform;

[0014] Step 2: After confirming the sinking sequence of the precast pile segments for negative skin friction, weld a fixture at the lower pile end steel hoop of the precast pile segment for negative skin friction at the bottom;

[0015] Step 3: Manufacture the inner sandwich stiffening tube and the outer sandwich stiffening tube with the same length as the precast pile segments for negative skin friction prepared in Step 1 at the construction site; first, sleeve the inner sandwich stiffening tube on the precast pile segment for negative skin friction at the bottom, then sleeve the outer sandwich stiffening tube on the outer periphery of the inner sandwich stiffening tube, and finally weld a flexible connector at the bottom of the inner sandwich stiffening tube and the outer sandwich stiffening tube. A limiting plate is fixedly provided at the bottom of the inner side wall of the inner sandwich stiffening tube of the precast pile segment for negative skin friction;

[0016] The lower edge of the limiting plate is provided with wing guards extending inward and outward, and the inner wing guard fastens the fixture;

[0017] Step 4: Drive the standard precast pile segments in accordance with the designed pile driving method. After the standard precast pile segments sink close to the ground, weld the bottom negative skin friction precast pile segment with the force conversion device to the pile end steel hoop at the upper end of the standard precast pile segment and continue to sink.

[0018] When the bottom negative skin friction precast pile segment sinks close to the ground, connect a new negative skin friction precast pile segment. Sleeve an inner sandwich stiffening tube and an outer sandwich stiffening tube that are adapted to the length of the negative skin friction precast pile segment from the inside to the outside on the outer periphery of the new negative skin friction precast pile segment. Among them, the newly sleeved inner sandwich stiffening tube and outer sandwich stiffening tube are respectively connected and communicated with the inner sandwich stiffening tube and outer sandwich stiffening tube of the adjacent original negative skin friction precast pile segment.

[0019] Step 5: Repeat Step 4 to complete the sinking of all negative skin friction precast pile segments and install the force conversion device.

[0020] Step 6: After all the standard precast pile segments and negative skin friction precast pile segments are completed and the pile top elevation is verified, on the one hand, cut the pile head of the topmost negative skin friction precast pile segment, and on the other hand, cut the excess parts of the inner sandwich stiffening tube and outer sandwich stiffening tube in the negative skin friction precast pile segment, ensuring that there are gaps between the tops of the inner sandwich stiffening tube and outer sandwich stiffening tube and the pile foundation cap. Then, install a fixing piece on the upper side wall of the negative skin friction precast pile segment with the pile head cut, fix a connecting plate on the fixing piece, and the connecting plate is fixedly connected to the top of the inner side wall of the inner sandwich stiffening tube of the negative skin friction precast pile segment.

[0021] Step 7: Inject water into the force conversion device, weld and seal the tops of the inner sandwich stiffening tube and outer sandwich stiffening tube with the same material, and all the processes are completed.

[0022] A construction method for a precast pile structure with a force conversion device includes the following steps:

[0023] Step 1: Determine the total thickness of the soil layer with negative skin friction at the pile forming point according to the geological exploration data, and prepare the negative skin friction precast pile segments that need to install the force conversion device. The negative skin friction precast pile segments are single or multiple and are connected in sequence, and the total length of the negative skin friction precast pile segments is slightly longer than the distance from the lower end of the negative skin friction soil layer to the bottom of the cap.

[0024] Step 2: After confirming the sinking sequence of the negative skin friction precast pile segments, weld a clamping piece at the lower pile end steel hoop of the bottommost skin friction precast pile segment.

[0025] Step 3: Sequentially sink the standard precast pile segments and negative skin friction precast pile segments in accordance with the designed pile driving method until all the pile segments reach the designed elevation.

[0026] Step 4: Measure the elevation of the pile top to obtain the elevation of the clip, and combine it with the elevation of the bottom of the bearing platform required by the design to calculate the length of the force conversion device; evenly segment the force conversion device according to its total length; weld the bottom of the inner and outer sandwich stiffening pipes of the bottommost segment with a flexible connector to form an integral force conversion device; weld the limit plate to the bottom of the inner sidewall of the inner sandwich stiffening pipe of the bottommost segment.

[0027] The lower edge of the limit plate is provided with wing guards extending inwards and outwards, and the inner wing guard fastens the clip.

[0028] Step 5: Sink the bottommost segment of the force conversion device in the pile sinking method as required by the design. When it is close to the ground during sinking, weld a new segment of the inner and outer sandwich stiffening pipes respectively from the inside out. The new inner sandwich stiffening pipe is welded to the upper end of the original inner sandwich stiffening pipe, and the outer sandwich stiffening pipe is welded to the upper end of the original inner sandwich stiffening pipe.

[0029] Step 6: Repeat Step 5; until the inner wing guard of the limit plate and the clip of the force conversion device are combined, which completes the sinking process of the force conversion device. Cut the pile head of the precast pile section for the topmost negative skin friction, then install a fixing piece on the side wall of the upper part of the precast pile section for the negative skin friction where the pile head is cut, and fix a connecting plate on the fixing piece, and the connecting plate is fixedly connected to the top of the inner sidewall of the inner sandwich stiffening pipe of the precast pile section for the negative skin friction.

[0030] Step 7: Inject water into the force conversion device, weld and seal the tops of the inner and outer sandwich stiffening pipes with the same material, and all processes are completed.

[0031] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0032] 1. The present invention utilizes the principle of the communicating vessel to convert negative skin friction into positive skin friction, achieving the purpose of converting adverse factors into favorable factors, and effectively improving the bearing capacity of precast piles; 2. Each structure of the force conversion device can be manufactured in the factory and assembled and constructed on site, which is simple and easy to operate; 3. It completely changes the situation of high investment caused by various measures that must be taken to overcome the adverse effects of negative skin friction in traditional designs, effectively reduces the project cost, and has significant social and economic benefits; 4. The structure of the precast pile body basically does not change, and only fixing pieces and clips are set on the precast pile according to requirements, effectively avoiding the increase in the manufacturing cost of the precast pile caused by excessive modification of the precast pile. Description of the Drawings

[0033] Figure 1 It is a longitudinal sectional view of the precast concrete pile and the force conversion device of the present invention;

[0034] Figure 2 is Figure 1 the transverse sectional view in

[0035] Figure 3 For Figure 1 Partial enlarged view at the middle wing and clamping part;

[0036] Figure 4 Longitudinal sectional view of the precast pile section and force conversion device for multi - stage negative skin friction of the present invention.

[0037] Label description: 1, bearing platform; 2, precast pile section for negative skin friction; 21, steel hoop; 22, clamping part; 23, middle wing; 3, force conversion device; 31, outer sandwich stiffening pipe; 32, inner sandwich stiffening pipe; 33, flexible connector; 34, wing plate; 35, stiffening plate; 4, liquid; 5, fixing part; 61, connecting plate, 62, limiting plate; 7, standard precast pile section. Specific implementation mode

[0038] The present invention will be described in detail below with reference to the accompanying drawings:

[0039] As Figures 1-3 shown: A force conversion device includes an outer sandwich stiffening pipe 31, an inner sandwich stiffening pipe 32 and a flexible connector 33; wherein the inner sandwich stiffening pipe 32 is sleeved on the outer wall surface of the pile structure and fixedly connected to the pile structure; the outer sandwich stiffening pipe 31 is sleeved on the outer periphery of the inner sandwich stiffening pipe 32, and a flexible connector 33 for connecting the inner cavities of the inner sandwich stiffening pipe 32 and the outer sandwich stiffening pipe 31 is connected to the bottoms of the inner sandwich stiffening pipe 32 and the outer sandwich stiffening pipe 31. A liquid 4 is provided in the inner sandwich stiffening pipe 32, the outer sandwich stiffening pipe 31 and the flexible connector 33, and the tops of the inner sandwich stiffening pipe 32 and the outer sandwich stiffening pipe 31 are both sealed;

[0040] Both the outer sandwich stiffening pipe 31 and the inner sandwich stiffening pipe 32 include an outer pipe body and an inner pipe body. The outer pipe body is sleeved on the outer periphery of the inner pipe body and there is a gap between the inner pipe body and the outer pipe body. The outer pipe body and the inner pipe body are connected by a plurality of vertically distributed stiffening plates 35;

[0041] A plurality of wing plates 34 are provided on the outer wall surface of the outer sandwich stiffening pipe 31 and are distributed from top to bottom and extend outwards.

[0042] The whole force conversion device can be understood as a U - shaped connector. When the ports of the connector are sealed, after one side of the vertical pipe part moves downwards, the liquid inside it will also move downwards, and correspondingly, the liquid in the other vertical pipe will move upwards, thereby driving the other vertical pipe to move upwards.

[0043] The inner wall surface of the outer sandwich stiffening pipe 31 and the outer wall surface of the inner sandwich stiffening pipe 32 are both smooth surfaces, and the outer wall surface of the outer sandwich stiffening pipe 31 is treated with anti - corrosion.

[0044] The outer extension length of the wing plate 34 ranges from 5 to 15 cm, and the distance between any two adjacent upper and lower wing plates 34 is twice the outer extension length of the wing plate 34.

[0045] The liquid is water. Water has a high cost performance as a liquid, and oil can also be used to prevent the force conversion device from rusting.

[0046] A precast pile structure with a force conversion device, the main body is several precast pile segments, and pile end steel hoops 21 are provided at the ends of the precast pile segments. Among them, the precast pile segments are divided into standard precast pile segments 7 and precast pile segments 2 for negative skin friction according to their position and function;

[0047] A force conversion device 3 is sleeved on the outer side wall of the precast pile segment 2 for negative skin friction; the force conversion device 3 mainly includes an outer sandwich stiffening tube 31, an inner sandwich stiffening tube 32 and a flexible connector 33; the inner sandwich stiffening tube 32 is sleeved on the outer side wall of the precast pile segment 2 for negative skin friction and is fixedly connected to the precast pile segment 2 for negative skin friction; the outer sandwich stiffening tube 31 is sleeved on the outer periphery of the inner sandwich stiffening tube 32, and a flexible connector 33 that connects the inner cavities of the outer sandwich stiffening tube 31 and the inner sandwich stiffening tube 32 is connected at the bottom of the inner sandwich stiffening tube 32 and the outer sandwich stiffening tube 31. A liquid 4 is provided in the inner sandwich stiffening tube 32, the outer sandwich stiffening tube 31 and the flexible connector 33, and the tops of the inner sandwich stiffening tube 32 and the outer sandwich stiffening tube 31 are both blocked;

[0048] Both the outer sandwich stiffening tube 31 and the inner sandwich stiffening tube 32 include an outer tube body and an inner tube body. The outer tube body is sleeved on the outer periphery of the inner tube body, and there is a gap between the inner tube body and the outer tube body. The outer tube body and the inner tube body are connected by a number of vertically distributed stiffening plates 35;

[0049] A plurality of wing plates 34 are provided on the outer side wall of the outer sandwich stiffening tube 31 and are distributed from top to bottom and extend outwards. The wing plates 34 generally extend into the surrounding soil layer.

[0050] Here, the precast piles are functionally divided into standard precast pile segments 7 and precast pile segments 2 for negative skin friction. The standard precast pile segments 7 have the same function as the current traditional precast pile structure. The precast pile segments 2 for negative skin friction mainly add a force conversion device 3 according to their function, and the position is mainly located in the soil layer where negative skin friction will occur.

[0051] At the top of the negative skin friction, a fixing member 5 is installed on the upper part of the precast pile section 2 for negative skin friction, and a connecting plate 61 is fixed on the fixing member 5. The top of the inner side wall surface of the inner sandwich stiffening pipe 32 of the precast pile section 2 for negative skin friction is fixedly connected to the connecting plate 61; at the bottom of the inner side wall surface of the inner sandwich stiffening pipe 32 of the precast pile section 2 for negative skin friction at the bottom, a limiting plate 62 is further connected. The lower edge of the limiting plate 62 is provided with protective wings 23 extending inwards and outwards. At the bottom end side wall steel hoop of the precast pile section 2 for negative skin friction at the bottom, a clamping member 22 is welded, and the inner protective wing 23 is fastened to the clamping member 22.

[0052] Here, the protective wings 23 extend inwards and outwards respectively. The protective wing 23 extending outwards can be located below the force conversion device to protect the force conversion device during the sinking process of the precast pile. The protective wing 23 extending inwards is buckled with the clamping member 22.

[0053] The force conversion device 3 is connected to the fixing member 5 of the precast pile section 2 for negative skin friction through the connecting plate 61 and the limiting plate 62. Here, on the outer side wall surface of the outer sandwich stiffening pipe 31, a plurality of wing plates 34 are provided and distributed from top to bottom and extend outwards, enabling the outer sandwich stiffening pipe 31 to be connected with the negative skin friction soil layer to form an integral body, so that when the negative skin friction soil layer sinks, it can drive the outer sandwich stiffening pipe 31 to sink; since the bottom of the outer sandwich stiffening pipe 31 and the inner sandwich stiffening pipe 32 are connected by a flexible connector 33, the compensation of the internal liquid can ensure that the inner sandwich stiffening pipe 32 receives an upward force generated by the liquid in the pipe, realizing the conversion of negative skin friction into positive skin friction.

[0054] The flexible connector 33 here is essentially a U-shaped connector, connecting the bottom of the outer sandwich stiffening pipe 31 and the bottom of the inner sandwich stiffening pipe 32.

[0055] Specifically, when the outer sandwich stiffening pipe 31 sinks, the water inside it will sink accordingly. Since the bottom of the outer sandwich stiffening pipe 31 and the inner sandwich stiffening pipe 32 are interconnected, the water in the inner sandwich stiffening pipe 32 will rise accordingly, thus making the inner sandwich stiffening pipe 32 have a tendency to move upward, forming positive skin friction.

[0056] A plurality of the standard precast pile sections 7 and the precast pile sections 2 for negative skin friction are provided; the clamping member 22 is welded to the side wall of the pile end steel hoop 21 at the bottom end of the corresponding precast pile section 2 for negative skin friction.

[0057] The inner side wall surface of the outer sandwich stiffening pipe 31 and the outer side wall surface of the inner sandwich stiffening pipe 32 are both smooth surfaces, and the outer side wall surface of the outer sandwich stiffening pipe 31 is subjected to anti-corrosion treatment. Since the outer sandwich stiffening pipe 31 here needs to contact the soil layer, in order to avoid rust and corrosion, the material needs to be subjected to anti-corrosion treatment.

[0058] The outer extension length of the wing plate 34 ranges from 5 to 15 cm, and the distance between any two adjacent upper and lower wing plates 34 is twice the outer extension length of the wing plate 34. Ensure that the outer sandwich stiffening pipe can be reliably connected to the negative skin friction soil layer, ensure that the negative skin friction soil layer can drive the outer sandwich stiffening pipe 31 to sink, and correspondingly cause the inner sandwich stiffening pipe 32 to form positive skin friction upward.

[0059] The liquid described above is water. It has a relatively high cost performance. Oil can also be used to avoid the rusting of the force conversion device.

[0060] Considering the differences in the installation methods of the precast pile and the force conversion device, that is, it is necessary to consider the combination of the precast pile and the force conversion device 3 and the construction of the precast pile. The specific construction methods are divided into the following two embodiments:

[0061] Embodiment 1

[0062] A construction method of a precast pile structure with a force conversion device, characterized by including the following steps:

[0063] Step 1: Determine the total thickness of the negative skin friction soil layer at the pile forming point according to the geological exploration data, and prepare the precast pile section 2 for negative skin friction that needs to install the force conversion device. The precast pile section 2 for negative skin friction is single or multiple and connected in sequence, and the total length of the precast pile section 2 for negative skin friction is slightly longer than the distance from the lower end of the negative skin friction soil layer to the bottom of the bearing platform 1;

[0064] Step 2: After confirming the sinking sequence of the precast pile section 2 for negative skin friction, weld a fixture 22 at the lower pile end steel hoop 21 of the precast pile section 2 for negative skin friction at the bottom;

[0065] Step 3: Fabricate the inner sandwich stiffening pipe 32 and the outer sandwich stiffening pipe 31 with the same length as the precast pile section 2 for negative skin friction prepared in Step 1 at the construction site; first, sleeved the inner sandwich stiffening pipe 32 on the precast pile section 2 for negative skin friction at the bottom, then sleeved the outer sandwich stiffening pipe 31 on the outer periphery of the inner sandwich stiffening pipe 32, and finally weld a flexible connector 33 at the bottom of the inner sandwich stiffening pipe 32 and the outer sandwich stiffening pipe 31. A limiting plate 62 is fixedly arranged at the bottom inner side wall of the inner sandwich stiffening pipe 32 of the precast pile section 2 for negative skin friction;

[0066] The lower edge of the limiting plate 62 is provided with protective wings 23 extending inwards and outwards, and the inner protective wing 23 buckles the fixture 22;

[0067] Step 4: Drive the standard precast pile section 7 by the pile driving method according to the design requirements. After the standard precast pile section 7 sinks close to the ground, weld the precast pile section 2 for negative skin friction with the force conversion device at the bottom in Step 3 to the pile end steel hoop 21 at the upper end of the standard precast pile section 7 and continue to sink;

[0068] At the bottom, the precast pile section 2 for negative skin friction sinks close to the ground, and a new precast pile section 2 for negative skin friction is connected. An inner sandwich stiffening pipe 32 and an outer sandwich stiffening pipe 31 that are adapted to the length of the precast pile section 2 for negative skin friction are sleeved on the outer periphery of the new precast pile section 2 for negative skin friction from the inside to the outside; wherein, the newly sleeved inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 are respectively connected and communicated with the inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 of the adjacent original precast pile section 2 for negative skin friction.

[0069] Step 5: Repeat Step 4 to complete the sinking of all precast pile sections 2 for negative skin friction and install the force conversion device.

[0070] Step 6: After all standard precast pile sections and precast pile sections 2 for negative skin friction are completed and the pile top elevation is verified, on the one hand, cut the pile head of the topmost precast pile section 2 for negative skin friction, and on the other hand, cut the excess parts of the inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 in the precast pile section 2 for negative skin friction, and ensure that there are gaps between the tops of the inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 and the pile foundation cap 1; then install a fixing member 5 on the upper side wall of the precast pile section 2 for negative skin friction where the pile head is cut, fix a connecting plate 61 on the fixing member 5, and the connecting plate 61 is fixedly connected to the top of the inner side wall of the inner sandwich stiffening pipe 32 of the precast pile section 2 for negative skin friction.

[0071] Step 7: Inject water into the force conversion device 3, weld and seal the tops of the inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 with the same material, and all processes are completed.

[0072] The above steps are equivalent to gradually forming the force conversion device during the pile sinking process. Specifically, during the pile sinking process, while connecting the precast pile section 2 for negative skin friction, the force conversion device 3 is synchronously installed and formed. That is, connect the precast pile section 2 for negative skin friction, and then install the inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 of the corresponding force conversion device; sink the pile; further connect a new precast pile section 2 for negative skin friction, and then install the inner sandwich stiffening pipe 32 and outer sandwich stiffening pipe 31 of the corresponding force conversion device, and so on.

[0073] Embodiment 2

[0074] A construction method for a precast pile structure with a force conversion device, characterized by including the following steps:

[0075] Step 1: Determine the total thickness of the soil layer with negative skin friction at the pile forming point according to the geological exploration data, and prepare the precast pile section 2 for negative skin friction that needs to install the force conversion device. The precast pile section 2 for negative skin friction is single or multiple and connected in sequence, and the total length of the precast pile section 2 for negative skin friction is slightly longer than the distance from the lower end of the soil layer with negative skin friction to the bottom of the cap 1.

[0076] Step 2: After confirming the sinking sequence of the precast pile section 2 for negative skin friction, weld a fixture 22 to the lower end pile end hoop 21 of the lowermost precast pile section 2 for skin friction;

[0077] Step 3: Sequentially sink the standard precast pile section 7 and the precast pile section 2 for negative skin friction in accordance with the pile sinking method required by the design until all pile sections reach the design elevation;

[0078] Step 4: Measure the pile top elevation to obtain the elevation of the fixture 22, and combine it with the elevation of the bottom of the bearing platform 1 required by the design to calculate the length of the force conversion device 3; evenly segment according to the total length of the force conversion device 3; weld the bottom of the inner sandwich stiffening tube 32 and the outer sandwich stiffening tube 31 of the lowermost segment with a flexible connector 33 to form the integral force conversion device 3; weld the limit plate 62 to the bottom of the inner wall of the inner sandwich stiffening tube 32 of the lowermost segment;

[0079] The lower edge of the limit plate 62 is provided with wing guards 23 extending inwards and outwards, and the inner wing guard 23 fastens the fixture 22;

[0080] Step 5: Sink the lowermost segment of the force conversion device 3 in accordance with the pile sinking method required by the design. When approaching the ground during sinking, weld a new segment of the inner sandwich stiffening tube 32 and the outer sandwich stiffening tube 31 from the inside outwards. The new segment of the inner sandwich stiffening tube 32 is welded to the upper end of the original inner sandwich stiffening tube 32, and the outer sandwich stiffening tube 31 is welded to the upper end of the original inner sandwich stiffening tube 32;

[0081] Step 6: Repeat Step 5; until the inner wing guard 23 of the limit plate 62 of the force conversion device 3 is combined with the fixture 22, which completes the sinking process of the force conversion device 3. Cut the pile head of the uppermost precast pile section 2 for negative skin friction, then install a fixing member 5 on the upper side wall surface of the precast pile section 2 for negative skin friction after cutting the pile head, fix the connecting plate 61 on the fixing member 5, and the connecting plate 61 is fixedly connected to the top of the inner wall of the inner sandwich stiffening tube 32 of the precast pile section 2 for negative skin friction;

[0082] Step 7: Inject water into the force conversion device 3, weld and seal the tops of the inner sandwich stiffening tube 32 and the outer sandwich stiffening tube 31 with the same material, and all processes are completed.

[0083] The above steps are equivalent to gradually forming the force conversion device after pile sinking. Specifically, during pile sinking, first complete the pile sinking of all precast pile sections (including the standard precast pile section 7 and the precast pile section 2 for negative skin friction), and then install and form the force conversion device. The force conversion device sinks in segments and gradually completes the complete splicing of the force conversion device.

[0084] The cross-section of precast piles commonly used in the engineering field at present is circular, and the schematic diagram of this application corresponds to this. There are also precast piles with square or even special-shaped cross-sections in the engineering field, and the cross-section of the corresponding force conversion device matches it, which will not be elaborated here.

[0085] It should be noted that generally, due to the problems of pile driving depth or the total thickness of the soil layer generating negative skin friction, multiple standard precast pile segments 7 and precast pile segments 2 for negative skin friction are usually prepared; however, if the pile driving depth or the total thickness of the soil layer generating negative skin friction may be different for each pile position, there may be only one standard precast pile segment 7 and one precast pile segment 2 for negative skin friction. In this case, the top precast pile segment 2 for negative skin friction and the bottom precast pile segment 2 for negative skin friction mentioned above are the same one.

[0086] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A force conversion device, characterized in that: The invention comprises an outer interlayer stiffening tube (31), an inner interlayer stiffening tube (32) and a flexible communicating tube (33); wherein the inner interlayer stiffening tube (32) is sleeved on the outer wall surface of the pile structure and is fixedly connected to the pile structure; the outer interlayer stiffening tube (31) is sleeved on the outer periphery of the inner interlayer stiffening tube (32); the bottoms of the inner interlayer stiffening tube (32) and the outer interlayer stiffening tube (31) are connected with a flexible communicating tube (33) for communicating the inner cavities of the inner interlayer stiffening tube (32) and the outer interlayer stiffening tube (31); liquid (4) is provided in the inner interlayer stiffening tube (32), the outer interlayer stiffening tube (31) and the flexible communicating tube (33); and the tops of the inner interlayer stiffening tube (32) and the outer interlayer stiffening tube (31) are both sealed; The outer interlayer stiffening tube (31) and the inner interlayer stiffening tube (32) both comprise an outer tube body and an inner tube body, the outer tube body is sleeved on the circumference of the inner tube body and a gap exists between the inner tube body and the outer tube body, and the outer tube body and the inner tube body are connected via a plurality of vertically distributed stiffening plates (35); A plurality of wing plates (34) distributed from top to bottom and extending outwards are provided on the outer wall surface of the outer sandwich stiffening tube (31).

2. A force conversion device according to claim 1, characterized in that: The inner wall surface of the outer interlayer stiffening tube (31) and the outer wall surface of the inner interlayer stiffening tube (32) are both smooth surfaces, and the outer wall surface of the outer interlayer stiffening tube (31) is subjected to anti-corrosion treatment.

3. A force conversion device according to claim 1, characterized in that: The outward extension length of the wing plate (34) is in the range of 5-15 cm, and the distance between any two vertically adjacent wing plates (34) is twice the outward extension length of the wing plate (34).

4. A force conversion device according to claim 1, characterized in that: The liquid is water.

5. A prefabricated pile structure with a force conversion device, characterized in that: The main body is a plurality of prefabricated pile segments, and the ends of the prefabricated pile segments are all provided with pile end steel hoops (21), wherein the prefabricated pile segments are divided into standard prefabricated pile segments (7) and prefabricated pile segments for negative friction resistance (2) according to their different positions and functions; The outer wall of the prefabricated pile section for negative friction resistance (2) is sleeved with a force conversion device (3); the force conversion device (3) mainly comprises an outer interlayer stiffening tube (31), an inner interlayer stiffening tube (32) and a flexible communicating vessel (33); wherein the inner interlayer stiffening tube (32) is sleeved on the outer wall of the prefabricated pile section for negative friction resistance (2) and is fixedly connected to the prefabricated pile section for negative friction resistance (2); the outer interlayer stiffening tube (31) is sleeved on the inner interlayer stiffening tube (32) and the inner interlayer stiffening tube (33) is sleeved on the outer wall of the prefabricated pile section for negative friction resistance (2) and is fixedly connected to the prefabricated pile section for negative friction resistance (2); 32), a flexible communicating vessel (33) is connected at the bottom of the inner interlayer stiffening tube (32) and the outer interlayer stiffening tube (31) to communicate the inner cavities of the outer interlayer stiffening tube (31) and the inner interlayer stiffening tube (32), a liquid (4) is provided in the inner interlayer stiffening tube (32), the outer interlayer stiffening tube (31) and the flexible communicating vessel (33), and the tops of the inner interlayer stiffening tube (32) and the outer interlayer stiffening tube (31) are both blocked; The outer interlayer stiffening tube (31) and the inner interlayer stiffening tube (32) both comprise an outer tube body and an inner tube body, the outer tube body is sleeved on the circumference of the inner tube body and a gap exists between the inner tube body and the outer tube body, and the outer tube body and the inner tube body are connected via a plurality of vertically distributed stiffening plates (35); A plurality of wing plates (34) distributed from top to bottom and extending outwards are provided on the outer wall surface of the outer sandwich stiffening tube (31).

6. A prefabricated pile structure with a force conversion device according to claim 5, characterized in that: A fixing member (5) is installed on the upper part of the prefabricated pile section (2) for negative friction resistance at the top, and a connecting plate (61) is fixed on the fixing member (5). The top of the inner wall surface of the inner sandwich stiffening tube (32) of the prefabricated pile section (2) for negative friction resistance is fixedly connected to the connecting plate (61); the bottom of the inner wall surface of the inner sandwich stiffening tube (32) of the prefabricated pile section (2) for negative friction resistance at the bottom is also connected to a limiting plate (62), and the lower edge of the limiting plate (62) is provided with a protective wing (23) extending inwardly and outwardly, and a clamping member (22) is welded to the side wall of the bottom end of the prefabricated pile section (2) for negative friction resistance at the bottom, and the inner protective wing (23) fastens the clamping member (22); The standard prefabricated pile segment (7) and the prefabricated pile segment (2) for negative friction resistance are both provided in plurality; the clamping piece (22) is welded to the side wall of the pile end steel hoop (21) at the bottom end of the corresponding prefabricated pile segment (2) for negative friction resistance.

7. The prefabricated pile structure with a force conversion device according to claim 5, characterized in that: The inner wall surface of the outer interlayer stiffening tube (31) and the outer wall surface of the inner interlayer stiffening tube (32) are both smooth surfaces, and the outer wall surface of the outer interlayer stiffening tube (31) is subjected to anti-corrosion treatment.

8. A construction method for a prefabricated pile structure with a force conversion device, characterized in that: The following steps are involved: Step 1: Determine the total thickness of the soil layer that will generate negative friction resistance at the pile formation point based on geological survey data, prepare a prefabricated pile segment (2) for negative friction resistance that needs to be installed with a force conversion device, the prefabricated pile segment (2) for negative friction resistance being a single pile or multiple piles connected in sequence, and the total length of the prefabricated pile segment (2) for negative friction resistance being slightly longer than the distance from the lower end of the soil layer for negative friction resistance to the bottom of the cap (1); Step 2: After confirming the sinking order of the prefabricated pile segments (2) for negative friction resistance, welding a clamp (22) to the lower end of the prefabricated pile segment (2) for friction resistance at the bottom; Step 3: at the construction site, produce an inner sandwich stiffening tube (32) and an outer sandwich stiffening tube (31) of the same length as the prefabricated pile section (2) for negative friction resistance prepared in step 1; firstly, sleeve the inner sandwich stiffening tube (32) on the bottommost prefabricated pile section (2) for negative friction resistance, then sleeve the outer sandwich stiffening tube (31) on the outer periphery of the inner sandwich stiffening tube (32), and finally weld a flexible connecting tube (33) to the bottom of the inner sandwich stiffening tube (32) and the bottom of the outer sandwich stiffening tube (31); a limiting plate (62) is fixedly provided at the bottom of the inner wall of the inner sandwich stiffening tube (32) of the prefabricated pile section (2) for negative friction resistance; The lower edge of the limiting plate (62) is provided with wings (23) extending inwardly and outwardly, and the inner wing (23) fastens the clamp (22); Step 4: sinking the standard prefabricated pile segment (7) in accordance with the pile sinking method required by the design. After the standard prefabricated pile segment (7) sinks close to the ground, the bottommost negative friction resistance prefabricated pile segment (2) with the force conversion device in step 3 is welded to the pile end steel hoop (21) at the upper end of the standard prefabricated pile segment (7) and the pile continues to sink. The bottommost prefabricated pile section (2) for negative friction resistance is sunk close to the ground, a new prefabricated pile section (2) for negative friction resistance is connected, and an inner sandwich stiffening tube (32) and an outer sandwich stiffening tube (31) that are adapted to the length of the prefabricated pile section (2) for negative friction resistance are sleeved from the inside to the outside of the outer periphery of the new prefabricated pile section (2) for negative friction resistance; wherein the newly sleeved inner sandwich stiffening tube (32) and outer sandwich stiffening tube (31) are respectively connected to and communicated with the inner sandwich stiffening tube (32) and outer sandwich stiffening tube (31) of the original adjacent prefabricated pile section (2) for negative friction resistance; Step 5: Repeat step 4 to complete the sinking of all negative friction resistance prefabricated pile segments (2) and the deployment of force conversion devices; Step 6: After all standard prefabricated pile segments and prefabricated pile segments for negative friction resistance (2) have been piled and the pile top elevation has been approved, the pile head of the topmost prefabricated pile segment for negative friction resistance (2) is cut, and the super-high parts of the inner sandwich stiffening tube (32) and the outer sandwich stiffening tube (31) in the prefabricated pile segment for negative friction resistance (2) are cut, and it should be ensured that there is a gap between the top of the inner sandwich stiffening tube (32) and the top of the outer sandwich stiffening tube (31) and the pile foundation cap (1); then, a fixing member (5) is installed on the upper side wall surface of the prefabricated pile segment for negative friction resistance (2) with the pile head cut, and a connecting plate (61) is fixed on the fixing member (5), and the connecting plate (61) is fixedly connected to the top of the inner side wall of the inner sandwich stiffening tube (32) of the prefabricated pile segment for negative friction resistance (2); Step 7: Water is injected into the force conversion device (3), and the tops of the inner sandwich stiffening tube (32) and the outer sandwich stiffening tube (31) are welded and sealed with the same material, and the entire process is completed.

9. A construction method for a prefabricated pile structure with a force conversion device, characterized in that: The following steps are involved: Step 1: Determine the total thickness of the soil layer that will generate negative friction resistance at the pile formation point based on geological survey data, prepare a prefabricated pile segment (2) for negative friction resistance that needs to be installed with a force conversion device, the prefabricated pile segment (2) for negative friction resistance being a single pile or multiple piles connected in sequence, and the total length of the prefabricated pile segment (2) for negative friction resistance being slightly longer than the distance from the lower end of the soil layer for negative friction resistance to the bottom of the cap (1); Step 2: After confirming the sinking order of the prefabricated pile segments (2) for negative friction resistance, welding a clamp (22) to the lower end steel hoop (21) of the prefabricated pile segment (2) for negative friction resistance at the bottom; Step 3: Sinking the standard prefabricated pile segments (7) and the prefabricated pile segments for negative friction resistance (2) in sequence according to the pile sinking method required by the design, until all the pile segments reach the designed elevation; Step 4: Measure the elevation of the pile top to obtain the elevation of the clamp (22), and calculate the length of the force conversion device (3) in combination with the bottom elevation of the pedestal (1) required by the design; divide the force conversion device (3) into sections evenly according to the total length; weld the bottom of the inner sandwich stiffening tube (32) and the outer sandwich stiffening tube (31) at the bottom to form the force conversion device (3) as a whole using a flexible connecting vessel (33); weld the limit plate (62) to the bottom of the inner wall of the inner sandwich stiffening tube (32) at the bottom; The lower edge of the limiting plate (62) is provided with wings (23) extending inwardly and outwardly, and the inner wing (23) fastens the clamp (22); Step 5: sink the lowest section of the force conversion device (3) by pile sinking according to the design requirements. When sinking close to the ground, weld a new section of the inner sandwich stiffening tube (32) and the outer sandwich stiffening tube (31) from the inside to the outside, wherein the new section of the inner sandwich stiffening tube (32) is welded to the upper end of the original inner sandwich stiffening tube (32), and the outer sandwich stiffening tube (31) is welded to the upper end of the original inner sandwich stiffening tube (32); Step 6: Repeat step 5 until the force conversion device (3) sinks to the point where the inner wing (23) of the limit plate (62) is combined with the clamp (22), thus completing the force conversion device (3) sinking process; the top of the prefabricated pile segment (2) for negative friction resistance is cut, and then a fixing member (5) is installed on the upper side wall surface of the prefabricated pile segment (2) for negative friction resistance with the pile head cut off, and a connecting plate (61) is fixed on the fixing member (5), and the connecting plate (61) is fixedly connected to the top of the inner side wall of the inner sandwich stiffening tube (32) of the prefabricated pile segment (2) for negative friction resistance; Step 7: Water is injected into the force conversion device (3), and the tops of the inner sandwich stiffening tube (32) and the outer sandwich stiffening tube (31) are welded and sealed with the same material, and the entire process is completed.

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