Double-wall steel pipe hole guiding device of stiff pipe pile
The design of the double-walled steel pipe borehole device solves the problems of complicated procedures, long construction period, and large soil displacement in the construction of rigid composite piles, and realizes efficient and environmentally friendly rigid pipe pile construction, which is suitable for various geological conditions.
Patent Information
- Application Number
- CN202423210832.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-24
- Publication Date
- 2025-12-26
- Estimated Expiration
- 2034-12-24
AI Technical Summary
The construction of rigid composite piles has problems such as complicated procedures, long construction period, high cost, large soil displacement effect, difficulty in coaxiality between concrete core piles and cement-soil piles, and difficulty in positioning during offshore construction.
The device employs a double-walled steel pipe borehole device, which includes an inner steel pipe, an outer steel pipe, and a precast pile tip. It forms a cement-soil ring structure by rotating and sinking. The inner steel pipe retains the soil core, while the outer steel pipe is sprayed with cement slurry for mixing. The groove design of the inner and outer steel pipes facilitates detachment. The device is equipped with a slurry nozzle and a retaining ring to reduce frictional resistance. The torque is transmitted by a synchronous plate, and the mixing blades improve the uniformity of mixing.
It simplifies construction processes, reduces construction time and costs, improves coaxiality, reduces soil displacement effect, ensures construction accuracy, adapts to various geological conditions, reduces pollution, and is suitable for various soil layers.
Smart Images
Figure CN223723742U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a double-wall steel pipe hole guiding device of a stiff pipe pile, which is used for constructing the stiff pipe pile. BACKGROUND
[0002] The stiff composite pile is a new type of pile foundation form, and the realization of the stiff composite pile is firstly to carry out the cement-soil pile forming, and then to press in the concrete core pile, so as to form a new pile type in which the concrete core pile and the cement-soil pile work together to bear the upper load. The stiff composite pile has the characteristics of the friction pile due to the large pile-soil extrusion interface and the improved load transmission path, so that the cement-soil pile has a much higher side resistance than the concrete pile, and the concrete core pile has a much higher pile body strength than the cement-soil pile, and the combination of the two can obtain a higher cost performance than the traditional pile type.
[0003] The main problems existing in the construction of the stiff composite pile foundation are that the pressing in of the cement-soil pile and the concrete core pile is two completely different construction processes, multiple devices are needed for cross operation, the construction process is more and more complicated, which leads to a long construction period and high cost; in the process of inserting the concrete core pile, the soil extrusion problem is easy to occur, which leads to the destruction of the adjacent piles and the adjacent buildings; it is difficult to ensure that the concrete core pile is inserted from the center of the cement-soil pile during the construction process, which leads to the phenomenon of different shafts of the concrete core pile and the cement-soil pile, greatly reducing the bearing capacity of the stiff composite pile. During the construction, if the upper part is an empty pile, it is very difficult to insert the pipe pile after the pile position of the cement-soil pile after the construction is difficult to find. In addition, for offshore operations, it is difficult to find the pile position of the cement-soil pile constructed in the early stage due to the seawater in the upper part, which leads to the difficulty of inserting the core pile. This leads to the limitation of the use of the stiff composite pile.
[0004] Therefore, how to simplify the construction process to reduce the construction period, improve the construction efficiency, and reduce the soil extrusion effect during the construction is still a problem to be solved for the stiff composite pile. In addition, when the upper part is an empty pile, how to accurately locate the cement-soil pile that has completed the construction to improve the coaxiality of the cement-soil pile and the core pile is also one of the problems to be solved during the construction of the stiff composite pile. UTILITY MODEL CONTENTS
[0005] To solve the problems in the prior art that two different construction processes are needed for the pressing of cement-soil piles and concrete core piles, leading to complicated construction procedures, long construction period, high cost, different shafts of the concrete core piles and the cement-soil piles, and difficulty in positioning the cement-soil piles, the application provides a double-wall steel pipe hole guiding device for a stiff pipe pile, which comprises an inner steel pipe, an outer steel pipe and a prefabricated pile tip, the prefabricated pile tip is a steel structural member, the prefabricated pile tip comprises an inner connecting pipe and an outer connecting pipe coaxially sleeved together, the inner connecting pipe is located on the inner side of the outer connecting pipe, the inner connecting pipe and the outer connecting pipe are both welded on the upper side of a ring-shaped plate, and a pile tip part in the shape of a cone protruding downward is arranged on the lower side of the ring-shaped plate; a core hole in the shape of a through hole is arranged in the prefabricated pile tip, and the core hole is coaxially arranged with the inner connecting pipe; the outer steel pipe is detachably clamped on the outer connecting pipe, the inner steel pipe is detachably clamped on the inner connecting pipe, and an annular cavity is formed between the inner steel pipe and the outer steel pipe; the core hole is connected to the inner cavity of the inner steel pipe through the inner connecting pipe.
[0006] An outer grouting nozzle for spraying cement mortar outside the outer steel pipe is arranged at the bottom of the outer steel pipe, and an outer grouting pipe is fixedly connected to the outer grouting nozzle.
[0007] When the hole guiding is performed by using the double-wall steel pipe hole guiding device and the stiff pipe pile is constructed, the steps are as follows:
[0008] (1) At a set position, a pile hole is drilled by using the pile machine to drive the double-wall steel pipe device, when the pile hole is drilled, the pile machine is clamped on the outer steel pipe, and under the driving of the pile machine, the double-wall steel pipe device rotates and sinks, at the same time, cement mortar is sprayed outside through the outer grouting nozzle, and the cement mortar is mixed with the underground soil to form a cement-soil annular structure;
[0009] (2) When the double-wall steel pipe device sinks to a set height, the hollow prestressed pipe pile is sunk into the annular cavity;
[0010] (3) First, the inner steel pipe is pulled upward, so that the soil in the inner steel pipe is retained underground;
[0011] Then, the outer steel pipe is rotated and pulled upward, at the same time, cement mortar is sprayed outside through the outer grouting nozzle, the cement-soil annular structure is stirred, and a cement-soil mixed pile is formed.
[0012] In the application, the core hole communicating with the inner steel pipe is arranged on the prefabricated pile tip, when the double-wall steel pipe device sinks into the underground and the hole guiding operation is performed, the underground soil can enter the inner steel pipe through the core hole, a soil core is formed, and the soil core is retained underground when the inner steel pipe is pulled out, so that the backfilling amount and the external transportation amount of the underground soil are reduced, and the construction cost is reduced. In the construction process, no underground soil is excavated to the ground, the whole process is free of mud slurry pollution, and the environmental protection requirement is met.
[0013] The inner cavity of the inner steel pipe is used to accommodate part of the underground soil, which reduces the soil squeezing effect and eliminates the threat to the completed underground pile and surrounding buildings. The core hole can also reduce the end resistance of the double-wall steel pipe device during sinking, which is more conducive to the sinking of the double-wall steel pipe device, thereby forming a larger diameter pile hole. The outer diameter of the stiff pipe pile formed by the application can reach more than 1 m.
[0014] When the double-wall steel pipe device is completed, an annular cavity for accommodating the hollow prestressed pipe pile with only an upward opening is formed, which solves the problem of positioning the completed cement-soil mixing pile when the upper part is empty. There is no problem of residual underground soil, and multiple hole cleaning is not required, so the hollow prestressed pipe pile can be sunk to the ground at one time. Since the inner steel pipe and the outer steel pipe are still underground during the sinking of the hollow prestressed pipe pile, the wall protection function can be completed, and the hole collapse or shrinkage phenomenon does not occur, so that the application has wide adaptability and can be constructed in coarse and fine sand, silt soft soil, and even pebble soil areas. The annular cavity is used to accommodate the hollow prestressed pipe pile, which effectively improves the coaxiality of the cement-soil mixing pile and the hollow prestressed pipe pile.
[0015] Further, to reduce the frictional resistance between the soil core and the inner steel pipe and reduce the amount of soil carried when the inner steel pipe is pulled out, an inner grouting nozzle is arranged at the bottom of the inner steel pipe, and an inner grouting pipe is fixedly connected to the inner grouting nozzle. The inner grouting nozzle is used to inject cement slurry into the inner steel pipe during the sinking of the double-wall steel pipe hole guide device, so as to form a layer of cement slurry isolation layer on the inner wall of the inner steel pipe. The cement slurry isolation layer can effectively reduce the frictional resistance between the soil core and the inner steel pipe.
[0016] Specifically, a first clamping groove is formed on the inner adapter, the first clamping groove is L-shaped, and the first clamping groove includes a first vertical slot extending in the vertical direction and a first horizontal slot connected to the bottom of the first vertical slot; in the opposite direction of the rotation direction of the double-wall steel pipe hole guide device, the first horizontal slot extends from the bottom of the first vertical slot in a direction away from the first vertical slot; a first protrusion is fixed to the outside of the bottom of the inner steel pipe, the first protrusion can enter the first horizontal slot through the first vertical slot, so that the inner steel pipe is clamped on the inner adapter and the inner steel pipe is lined inside the inner adapter; rotating the inner steel pipe in the rotation direction of the double-wall steel pipe hole guide device can make the first protrusion enter the first vertical slot from the first horizontal slot, and when the inner steel pipe is lifted upward, the inner steel pipe can be separated from the inner adapter;
[0017] A second clamping slot is formed on the outer connecting pipe, which is L-shaped and includes a second vertical slot extending in the vertical direction and a second horizontal slot connected to the bottom of the second vertical slot; in the rotation direction of the double-walled steel pipe guide hole device, the second horizontal slot extends from the bottom of the second vertical slot in a direction away from the second vertical slot; a second protrusion is fixed to the inner side of the bottom of the outer steel pipe, which enters the second horizontal slot through the second vertical slot, so that the outer steel pipe is clamped on the outer connecting pipe and the outer steel pipe is sleeved on the outer side of the outer connecting pipe; rotating the outer steel pipe in the opposite direction of the rotation direction of the double-walled steel pipe guide hole device can make the second protrusion enter the second vertical slot from the second horizontal slot, and when the outer steel pipe is lifted upward, the outer steel pipe can be separated from the outer connecting pipe.
[0018] The design can smoothly separate the inner steel pipe and the outer steel pipe from the connected inner connecting pipe and outer connecting pipe for recycling. Since the inner steel pipe is lined inside the inner connecting pipe and the outer steel pipe is sleeved on the outer side of the outer connecting pipe, it can effectively prevent underground soil from entering the gap between the inner steel pipe and the inner connecting pipe and the gap between the outer steel pipe and the outer connecting pipe, causing the first clamping slot or the second clamping slot to be blocked and affecting the recycling of the inner steel pipe or the outer steel pipe.
[0019] Further, an outer retaining ring is provided on the outer wall of the outer connecting pipe, and when the outer steel pipe is clamped on the outer connecting pipe, the outer steel pipe abuts against the outer retaining ring or has a gap of no more than 5mm between the outer steel pipe and the outer retaining ring; an inner retaining ring is provided on the inner wall of the core hole, and when the inner steel pipe is clamped on the inner connecting pipe, the inner steel pipe abuts against the inner retaining ring or has a gap of no more than 5mm between the inner steel pipe and the inner retaining ring.
[0020] After the inner retaining ring is provided, underground soil at most enters the gap between the inner steel pipe and the inner retaining ring, but not the gap between the inner connecting pipe and the inner steel pipe. By providing the outer retaining ring, underground soil at most enters the gap between the outer steel pipe and the outer retaining ring, but not the gap between the outer connecting pipe and the outer steel pipe. To prevent underground soil from entering the gap between the inner steel pipe and the inner retaining ring and the gap between the outer connecting pipe and the outer steel pipe, during the specific construction process, if the outer steel pipe and the outer retaining ring are not easy to seal, a sealing ring can be provided between the outer steel pipe and the outer retaining ring to close the gap between the outer steel pipe and the outer retaining ring. If the inner steel pipe and the inner retaining ring are not easy to seal, a sealing ring can be provided between the inner steel pipe and the inner retaining ring to close the gap between the inner steel pipe and the inner retaining ring.
[0021] Further, in the radial direction, the outer circumferential surface of the outer retaining ring does not exceed the outer circumferential surface of the outer steel pipe outwardly; and in the radial direction, the inner circumferential surface of the inner retaining ring exceeds the inner circumferential surface of the inner steel pipe inwardly. That is, the outer diameter of the outer retaining ring is not greater than the outer diameter of the outer steel pipe, and the inner diameter of the inner retaining ring is less than the inner diameter of the inner steel pipe.
[0022] When the outer circumferential surface of the outer blocking ring does not exceed the outer circumferential surface of the outer steel pipe, the outer diameter of the double-wall steel pipe device in the radial direction can be reduced, and the resistance of the underground soil to the sinking of the double-wall steel pipe device can be reduced. When the inner circumferential surface of the inner blocking ring exceeds the inner circumferential surface of the inner steel pipe, the underground soil can be compressed when passing through the core hole and entering the inner steel pipe, so that the outer diameter of the soil core is smaller than the inner diameter of the inner steel pipe. Although the soil core will still contact the inner wall of the inner steel pipe after entering the inner steel pipe, the frictional resistance between the soil core and the inner steel pipe will still be reduced, which is beneficial to the soil core remaining in the ground when the inner steel pipe is pulled out. Preferably, the inner diameter of the inner blocking ring is 5-10 mm smaller than the inner diameter of the inner steel pipe.
[0023] Further, to improve the mixing uniformity of the cement slurry and the underground soil, a stirring blade is arranged at the bottom of the outer steel pipe, and the stirring blade is located outside the outer steel pipe. Preferably, the stirring outer diameter of the stirring blade is 1.5-2.5 times the outer diameter of the hollow prestressed pipe pile. The structure of the stirring blade is not particularly limited in the present application, and the stirring blades of existing stirring piles can be applied to the present application, such as spiral stirring blades, plate stirring blades, etc.
[0024] Further, to improve the transmission of the torsion between the inner steel pipe and the outer steel pipe, an inner clamping groove is arranged on the outer wall of the inner steel pipe, an outer clamping groove is arranged on the inner wall of the outer steel pipe, a synchronous plate is inserted in the vertical direction in the annular cavity, and the opposite sides of the synchronous plate are respectively inserted in the inner clamping groove and the outer clamping groove. The synchronous plate is used as a torsion transmission piece between the inner steel pipe and the outer steel pipe, so that the outer steel pipe uniformly transmits the torque generated by the external force to the inner steel pipe.
[0025] Preferably, the synchronous plate is located at the top of the annular cavity. The height of the synchronous plate is controlled to be between 0.3-2 meters. BRIEF DESCRIPTION OF DRAWINGS
[0026] Figure 1 is a structural schematic diagram of an embodiment of the double-wall steel pipe guide hole device.
[0027] Figure 2 is a state diagram of the prefabricated pile tip separated from the inner steel pipe and the outer steel pipe in the double-wall steel pipe guide hole device.
[0028] Figure 3 is Figure 2 is an enlarged view of A-A in
[0029] Figure 4 is Figure 3 is an enlarged view of B in
[0030] Figure 5 is a structural schematic diagram of the prefabricated pile tip.
[0031] Figure 6 is a three-dimensional structural diagram of the prefabricated pile tip.
[0032] Figure 7 is a construction flow chart of the construction of the stiff pipe pile by using the double-wall steel pipe hole guiding device. DETAILED DESCRIPTION
[0033] The double-wall steel pipe hole guiding device of the stiff pipe pile is described below, please refer to Figures 1-6 The double-wall steel pipe hole guiding device includes an inner steel pipe 12, an outer steel pipe 11 and a prefabricated pile tip 20, the prefabricated pile tip 20 is a steel structure, the prefabricated pile tip 20 includes an annular plate 23 and an inner connecting pipe 22 and an outer connecting pipe 21 welded on the upper side of the annular plate, the inner connecting pipe 22 and the outer connecting pipe 21 are coaxially sleeved together, wherein the inner connecting pipe is located on the inner side of the outer connecting pipe.
[0034] A downwardly protruding pile tip part in the shape of a cone is welded on the lower side of the annular plate, the pile tip part includes a cylindrical core pipe 25 extending in the vertical direction and a conical pipe 24 welded on the outer side of the core pipe 25, the small end of the conical pipe faces downward, the inner cavity of the core pipe is formed into a core hole 28, the core hole is a through hole, so that the core hole penetrates downward through the conical pipe, the core hole is coaxially arranged with the inner connecting pipe and communicates with the inner cavity of the inner connecting pipe.
[0035] The outer steel pipe is detachably clamped on the outer connecting pipe, the inner steel pipe is detachably clamped on the inner connecting pipe, an annular cavity 17 is formed between the inner steel pipe and the outer steel pipe. A pile tip cavity 29 in the shape of an annular ring with an upward opening is formed between the inner connecting pipe and the outer connecting pipe, the annular cavity 17 communicates with the pile tip cavity 29. The core hole communicates with the inner cavity of the inner steel pipe through the inner connecting pipe, when the double-wall steel pipe hole guiding device works, underground soil can enter into the inner steel pipe through the core hole to form a soil core 33.
[0036] Specifically in this embodiment, three first clamping grooves 221 are formed on the inner connecting pipe 22, the three first clamping grooves are uniformly arranged in the circumferential direction, the first clamping groove 221 is in the shape of L, each first clamping groove 221 includes a first vertical groove 222 extending in the vertical direction and a first horizontal groove 223 connected to the bottom of the first vertical groove; in the opposite direction of the rotation direction of the double-wall steel pipe hole guiding device, the first horizontal groove extends from the bottom of the first vertical groove in the direction away from the first vertical groove, Figure 6 The direction of the arrow S in the figure indicates the rotation direction of the double-wall steel pipe hole guiding device.
[0037] Three first protrusions 121 are welded on the outer side of the bottom of the inner steel pipe, each first protrusion 121 can enter into the first horizontal groove through the first vertical groove of a first clamping groove, so that the inner steel pipe is clamped on the inner connecting pipe and the inner steel pipe is lined inside the inner connecting pipe. Rotating the inner steel pipe in the rotation direction of the double-wall steel pipe hole guiding device can make the first protrusion enter into the first vertical groove from the first horizontal groove, and when the inner steel pipe is lifted upward, the inner steel pipe can be separated from the inner connecting pipe.
[0038] Three second clamping grooves 211 are formed on the outer connecting pipe 21, and the three second clamping grooves are evenly arranged in the circumferential direction. The second clamping groove 211 is in the shape of L, and each second clamping groove 211 includes a second vertical groove 212 extending in the vertical direction and a second horizontal groove 213 connected to the bottom of the second vertical groove. In the direction of rotation of the double-wall steel pipe guide hole device, the second horizontal groove extends from the bottom of the second vertical groove in a direction away from the second vertical groove.
[0039] Three second protrusions 111 are welded to the inner side of the bottom of the outer steel pipe. Each second protrusion 111 can enter the second horizontal groove through the second vertical groove of a second clamping groove, so that the outer steel pipe is clamped on the outer connecting pipe and the outer steel pipe is sleeved on the outer side of the outer connecting pipe. Rotating the outer steel pipe in the opposite direction of the direction of rotation of the double-wall steel pipe guide hole device can make the second protrusion enter the second vertical groove from the second horizontal groove, and when the outer steel pipe is lifted upward, the outer steel pipe can be separated from the outer connecting pipe.
[0040] In this embodiment, three first clamping grooves and three second clamping grooves are provided. In this application, the number of first clamping grooves and second clamping grooves is not strictly required. However, in order to facilitate the rotation of the double-wall steel pipe guide hole device along the central axis, at least two first clamping grooves and two second clamping grooves are required. When only two first clamping grooves and two second clamping grooves are provided, the two first clamping grooves need to be oppositely arranged, and the two second clamping grooves also need to be oppositely arranged. The number of first clamping grooves and second clamping grooves is controlled within 2-10.
[0041] In order to avoid the soil entering the first clamping groove or the second clamping groove when the double-wall steel pipe guide hole device works underground, which hinders the rotation of the inner steel pipe or the outer steel pipe, causing the inner steel pipe to be unable to separate from the inner connecting pipe, or causing the outer steel pipe to be unable to separate from the outer connecting pipe, in this embodiment, the outer circumferential surface of the annular plate 23 outwardly exceeds the outer circumferential surface of the outer connecting pipe and forms an annular outer blocking ring 231. When the outer steel pipe is clamped on the outer connecting pipe, the outer steel pipe tightly abuts against the outer blocking ring to close the gap between the outer steel pipe and the outer connecting pipe. Of course, in other embodiments, the outer blocking ring can also be separately provided. It can be understood that in other embodiments, a gap of not more than 5mm can be provided between the outer steel pipe and the outer blocking ring, and a sealing ring can be provided in the gap to close the gap between the outer steel pipe and the outer connecting pipe.
[0042] In the radial direction, the outer circumferential surface of the annular plate 23 does not outwardly exceed the outer circumferential surface of the outer steel pipe; that is, in the radial direction, the outer circumferential surface of the outer blocking ring does not outwardly exceed the outer circumferential surface of the outer steel pipe, so as to reduce the resistance when the double-wall steel pipe guide hole device is drilled downward in the soil.
[0043] In the embodiment, the inner diameter of the core tube 25 is smaller than the inner diameter of the inner steel tube in the radial direction, so that the core tube simultaneously serves as an inner retainer, and when the inner steel tube is clamped on the inner adapter, the inner steel tube is tightly pressed against the top end face 251 of the core tube 25, thereby closing the gap between the inner steel tube and the top end face of the core tube 25. Of course, in other embodiments, the inner retainer can also be separately provided. It can be understood that in other embodiments, a gap of not more than 5 mm can also be provided between the inner steel tube and the top end face of the core tube 25, and a sealing ring is provided in the gap, and the sealing ring is used to close the gap between the outer steel tube and the top end face of the core tube 25.
[0044] In the embodiment, the inner diameter of the core tube 25 is smaller than the inner diameter of the inner steel tube, so that in the radial direction, the inner periphery of the core tube 25 is inwardly beyond the inner periphery of the inner steel tube; that is, in the radial direction, the inner periphery of the inner retainer is inwardly beyond the inner periphery of the inner steel tube. During construction, the underground soil will enter the inner steel tube to form a soil core 33. When the underground soil passes through the core hole, the underground soil will be compressed, so that the formed soil core has an outer diameter smaller than the inner diameter of the inner steel tube. Although the soil core will still be in contact with the inner wall of the inner steel tube after entering the inner steel tube, the frictional resistance between the soil core and the inner steel tube will be reduced, so that when the inner steel tube is pulled out, it is more beneficial to keep the soil core underground.
[0045] The inner diameter of the core tube 25 is preferably 5-10 mm smaller than the inner diameter of the inner steel tube, and in the embodiment, the inner diameter of the core tube 25 is 8 mm smaller than the inner diameter of the inner steel tube. That is, the inner diameter of the inner retainer is 8 mm smaller than the inner diameter of the inner steel tube.
[0046] The inner grouting pipe 272 and the outer grouting pipe 271 are arranged in the annular cavity. The inner grouting pipe and the outer grouting pipe are both connected to the grouting equipment through the rotary joint.
[0047] An inner grouting ring pipe 274 is welded at the bottom of the inner grouting pipe, and three inner jetting nozzles 262 are installed at the bottom of the inner steel tube. The three inner jetting nozzles 262 are uniformly and spacedly arranged along the circumferential direction of the inner steel tube, and each inner jetting nozzle is connected to the inner cavity of the inner steel tube after penetrating the pipe wall of the inner steel tube. The inner grouting ring pipe extends along the outer wall of the inner steel tube and is attached to the outer wall of the inner steel tube, and the inner grouting pipe is attached to the outer wall of the inner steel tube and extends upward in the vertical direction out of the annular cavity.
[0048] An outer grouting ring pipe 273 is welded at the bottom of the outer grouting pipe, and three outer jetting nozzles 261 are installed at the bottom of the outer steel tube. The three outer jetting nozzles 261 are uniformly and spacedly arranged along the circumferential direction of the outer steel tube, and each outer jetting nozzle is connected to the outside of the outer steel tube after penetrating the pipe wall of the outer steel tube. The outer grouting ring pipe extends along the inner wall of the outer steel tube and is attached to the inner wall of the outer steel tube, and the outer grouting pipe is attached to the inner wall of the outer steel tube and extends upward in the vertical direction out of the annular cavity.
[0049] In order to improve the uniformity of the torque transmission between the outer steel pipe and the inner steel pipe, three inner clamping piece groups are welded on the outer wall of the inner steel pipe, each of which includes five inner clamping pieces 11 arranged in the vertical direction, each of which has an inner clamping groove facing the outside in the radial direction, which penetrates the upper and lower end faces of the inner clamping piece in the vertical direction.
[0050] Three outer clamping piece groups are welded on the inner wall of the outer steel pipe, each of which includes five outer clamping pieces 152 arranged in the vertical direction, each of which has an outer clamping groove facing the inside in the radial direction, which penetrates the upper and lower end faces of the outer clamping piece in the vertical direction. Each inner clamping piece group is arranged opposite to an outer clamping piece group in the radial direction, and the opposite inner clamping piece group and the outer clamping piece group together form a clamping piece combination. For each clamping piece combination, a synchronization plate 16 is arranged, which is inserted into the annular cavity 17 in the vertical direction, and the opposite sides of the synchronization plate are inserted into the inner clamping groove and the outer clamping groove of the corresponding clamping piece combination. By using the synchronization plate, the outer steel pipe uniformly transmits the torque generated by the external force to the inner steel pipe.
[0051] Since the bottom of the inner steel pipe and the bottom of the outer steel pipe are connected to the prefabricated pile tip, the inner steel pipe and the outer steel pipe can transmit torque through the prefabricated pile tip. Therefore, in another embodiment, each inner clamping piece group can only have one inner clamping piece located at the top of the inner steel pipe, and each outer clamping piece group can only have one outer clamping piece located at the top of the outer steel pipe. The height of the synchronization plate is shortened, and the synchronization plate is only arranged at the top of the inner steel pipe and the outer steel pipe, i.e. the top of the annular cavity. When the synchronization plate is only arranged at the top of the inner steel pipe and the outer steel pipe, the height of the synchronization plate can be controlled between 0.3-2 meters, specifically 0.3 meters, 0.5 meters, 1 meter, 1.5 meters or 2 meters, or other data between 0.3-2 meters.
[0052] In this embodiment, the inner clamping piece and the outer clamping piece are made of channel steel, and the groove of the channel steel extends in the vertical direction, and the groove of the channel steel is used as the inner clamping groove and the outer clamping groove.
[0053] In order to strengthen the mixing of cement slurry and underground soil, stirring blades 13 are arranged at the bottom of the outer steel pipe, which are located on the outside of the outer steel pipe, and the stirring outer diameter of the stirring blade 13 is 2 times the outer diameter of the hollow prestressed pipe pile. It can be understood that in other embodiments, the stirring outer diameter of the stirring blade 13 is 1.5 times, 1.8 times, 2.2 times or 2.5 times the outer diameter of the hollow prestressed pipe pile, of course, it can also be other multiples between 1.5-2.5 times.
[0054] In order to more clearly describe the double-wall steel pipe hole guiding device in this application, the construction method of using the above-mentioned double-wall steel pipe hole guiding device in the construction of the stiff pipe pile is described below. Please refer to Figure 7The construction method comprises the following steps:
[0055] (1) Please refer to steps (a) and (b) in Figure 7 , at a set position, a pile hole is drilled by using a pile machine to drive a double-wall steel pipe hole guide device, while drilling the pile hole, the power head of the pile machine is clamped on the outer steel pipe, and the double-wall steel pipe hole guide device rotates and sinks under the driving of the pile machine. During the rotation and sinking of the double-wall steel pipe hole guide device, underground soil enters the inner cavity of the inner steel pipe through the core hole 28 to form a soil core 33. Figure 7 In , mark 100 represents the ground.
[0056] During the rotation and sinking of the double-wall steel pipe hole guide device, the cement slurry is sprayed outward through the outer jetting nozzle, and the cement slurry sprayed outside the outer steel pipe is mixed with the underground soil under the stirring of the stirring blade to form a cement-soil annular structure 31. The cement slurry is injected into the inner steel pipe through the inner jetting nozzle at the same time, and a layer of cement slurry isolation layer is formed on the inner wall of the inner steel pipe, which is located between the soil core and the inner steel pipe, and the frictional resistance between the soil core and the inner steel pipe is reduced by using the cement slurry isolation layer.
[0057] (2) Please refer to step (c) in Figure 7 , when the double-wall steel pipe hole guide device sinks to a set height, the synchronous plate is first pulled out, and then the hollow prestressed pipe pile 32 is sunk into the annular cavity.
[0058] (3) Please refer to steps (d) and (e) in Figure 7 , before the cement-soil mixing pile completes initial setting, the inner steel pipe and the outer steel pipe are pulled out in sequence, so that the soil core in the inner steel pipe is left underground.
[0059] When the inner steel pipe is pulled out, first rotate the inner steel pipe in the rotation direction of the double-wall steel pipe hole guide device, so that the first protrusion enters the first vertical slot from the first horizontal slot, then lift the inner steel pipe upward to separate the inner steel pipe from the inner adapter, and then completely pull out the inner steel pipe from the ground only by lifting it upward. It can be understood that in another embodiment, after the inner steel pipe is separated from the inner adapter, the inner steel pipe can also be completely pulled out from the ground by rotating and lifting it upward.
[0060] When the outer steel pipe is pulled out, first rotate the outer steel pipe in the opposite direction of the rotation direction of the double-wall steel pipe hole guide device, so that the second protrusion enters the second vertical slot from the second horizontal slot, then lift the outer steel pipe upward to separate the outer steel pipe from the outer adapter; then rotate the outer steel pipe upward to pull it out, and continue to spray cement slurry through the outer jetting nozzle to stir the cement-soil annular structure to form a cement-soil mixing pile 34. When the outer steel pipe is completely pulled out, the construction of the stiff pipe pile is completed.
Claims
1. A double-wall steel pipe hole guiding device of a ductile pipe pile, characterized by, The double-wall steel pipe hole guiding device comprises an inner steel pipe, an outer steel pipe and a prefabricated pile tip, the prefabricated pile tip is a steel structural member, the prefabricated pile tip comprises coaxially sleeved inner and outer connecting pipes, the inner connecting pipe is located inside the outer connecting pipe, the inner and outer connecting pipes are welded on the upper side of a ring-shaped plate, the lower side of the ring-shaped plate is provided with a downwardly protruding pile tip part in a conical shape, a core hole in a through hole shape is arranged in the prefabricated pile tip, the core hole is coaxially arranged with the inner connecting pipe, the outer steel pipe is detachably clamped on the outer connecting pipe, the inner steel pipe is detachably clamped on the inner connecting pipe, and an annular cavity is formed between the inner steel pipe and the outer steel pipe; the core hole is communicated with the inner cavity of the inner steel pipe through the inner connecting pipe. An outer grouting nozzle for grouting outside the outer steel pipe is arranged at the bottom of the outer steel pipe, and an outer grouting pipe is fixedly connected to the outer grouting nozzle.
2. The double wall steel pipe pilot hole device of claim 1, wherein, An inner grouting nozzle is arranged at the bottom of the inner steel pipe, and an inner grouting pipe is fixedly connected to the inner grouting nozzle, the inner grouting nozzle is used for injecting cement slurry into the inner steel pipe to form a cement slurry isolation layer on the inner wall of the inner steel pipe when the double-wall steel pipe hole guiding device is sinking.
3. The double wall steel pipe pilot hole device of claim 1, wherein, A first clamping groove is arranged on the inner connecting pipe, the first clamping groove is in an L shape, the first clamping groove comprises a first vertical groove extending in a vertical direction and a first horizontal groove connected to the bottom of the first vertical groove, the first horizontal groove extends from the bottom of the first vertical groove in a direction away from the first vertical groove in the opposite direction of the rotation direction of the double-wall steel pipe hole guiding device, a first protruding block is fixedly arranged outside the bottom of the inner steel pipe, the first protruding block can enter the first horizontal groove through the first vertical groove, so that the inner steel pipe is clamped on the inner connecting pipe and the inner steel pipe is lined inside the inner connecting pipe, The inner steel pipe is rotated in the rotation direction of the double-wall steel pipe hole guiding device, so that the first protruding block enters the first vertical groove from the first horizontal groove, and when the inner steel pipe is lifted upward, the inner steel pipe can be separated from the inner connecting pipe. A second clamping groove is arranged on the outer connecting pipe, the second clamping groove is in an L shape, the second clamping groove comprises a second vertical groove extending in a vertical direction and a second horizontal groove connected to the bottom of the second vertical groove, the second horizontal groove extends from the bottom of the second vertical groove in a direction away from the second vertical groove in the rotation direction of the double-wall steel pipe hole guiding device, a second protruding block is fixedly arranged inside the bottom of the outer steel pipe, the second protruding block can enter the second horizontal groove through the second vertical groove, so that the outer steel pipe is clamped on the outer connecting pipe and the outer steel pipe is sleeved outside the outer connecting pipe, the outer steel pipe is rotated in the opposite direction of the rotation direction of the double-wall steel pipe hole guiding device, so that the second protruding block enters the second vertical groove from the second horizontal groove, and when the outer steel pipe is lifted upward, the outer steel pipe can be separated from the outer connecting pipe.
4. The double wall steel pipe pilot hole apparatus of claim 3, wherein, An outer stop ring is arranged on the outer wall of the outer connecting pipe, when the outer steel pipe is clamped on the outer connecting pipe, the outer steel pipe abuts against the outer stop ring or there is a gap of not more than 5 mm between the outer steel pipe and the outer stop ring, an inner stop ring is arranged on the inner wall of the core hole, when the inner steel pipe is clamped on the inner connecting pipe, the inner steel pipe abuts against the inner stop ring or there is a gap of not more than 5 mm between the inner steel pipe and the inner stop ring.
5. The double wall steel pipe pilot hole apparatus of claim 4, wherein, In the radial direction, the outer periphery of the outer stop ring does not exceed the outer periphery of the outer steel pipe outwardly, and in the radial direction, the inner periphery of the inner stop ring exceeds the inner periphery of the inner steel pipe inwardly.
6. The double wall steel pipe pilot hole apparatus of claim 1 wherein, A stirring blade is arranged at the bottom of the outer steel pipe, and the stirring blade is located outside the outer steel pipe.
7. The double wall steel pipe pilot hole apparatus of claim 6, wherein, The outer diameter of the stirring blade is 1.5-2.5 times of the outer diameter of the hollow prestressed pipe pile.
8. The double wall steel pipe pilot hole device of claim 1, wherein, The inner steel pipe is provided with an inner clamping groove on the outer wall, and the outer steel pipe is provided with an outer clamping groove on the inner wall, and the synchronous plate is inserted in the vertical direction in the annular cavity, and the opposite sides of the synchronous plate are respectively inserted in the inner clamping groove and the outer clamping groove.
9. The double wall steel pipe pilot hole apparatus of claim 8, wherein, The synchronous plate is located at the top of the annular cavity.