Pile bottom grouting system based on hollow pile and pile bottom grouting method

Abstract

The present invention provides a pile bottom grouting system based on a hollow pile and a pile bottom grouting method thereof. A pile bottom plate is provided at the bottom of the hollow pile, a slurry outlet hole is provided on the pile bottom plate, and the slurry outlet hole is movably connected with a protective component hole; a slurry relay device is provided on the upper surface of the pile bottom plate, the slurry relay device includes a slurry relay chamber and a docking device, the slurry relay chamber and the slurry outlet hole are connected, and the docking device is used to connect with a movable grouting pipe in the hollow pile, and after the grouting pressure reaches a set value, the slurry flows out from the slurry outlet hole. The present invention performs pile bottom grouting by cooperating with a movable grouting pipe and a slurry relay device, thereby reducing the influence of grouting on pile pressing construction, and the grouting pipe can be reused; in addition, the grouting hole is provided with a protective component, which can prevent soil from entering during pile pressing, and the grouting hole can be opened under the pressure of grouting without affecting normal grouting.

Description

Technical Field

[0001] The invention relates to building pile foundation construction, and in particular to a pile bottom grouting system based on a hollow pile and a pile bottom grouting method thereof. Background Art

[0002] Hollow piles are mainly divided into two categories: precast concrete piles and steel piles. Hollow piles can withstand large loads, have reliable pile body quality, fast construction speed, and economical engineering cost. They are one of the widely used pile types in pile foundation engineering. Hollow piles are widely used in engineering due to factors such as small construction impact and mature pile making technology. Commonly used hollow piles are precast concrete pipe piles and steel pipe piles.

[0003] At present, the commonly used hollow piles in China are generally not equipped with grouting devices. During the application process, it is often difficult to fully exert the bearing capacity of the pile body due to construction or soil layer reasons, resulting in the phenomenon that the bearing capacity of a single pile is far lower than the bearing capacity of the pile body. The main reason is that the soil layer strength on the pile side and pile end is insufficient and cannot provide sufficient pile side friction resistance and pile end resistance. Therefore, the grouting technology of the pile side and pile end of the hollow pile has gradually begun to develop. However, the current hollow pile grouting technology has the following disadvantages:

[0004] 1) The grouting pipe needs to be buried in sections during the pile driving construction, which has a great impact on the efficiency of the pile driving construction;

[0005] 2) Grouting pipes cannot be reused and have high use costs;

[0006] 3) Pre-buried grouting pipes are prone to local leakage, damage, etc., and are difficult to replace;

[0007] 4) There is a lack of measures to prevent slurry from flowing back, and slurry refluxes after grouting is stopped, affecting the grouting effect.

[0008] Application No. 202111192808.0 discloses a structure and method for grouting at the end of a PHC pile. The patent uses a grouting plug to fill a closed space between the inner wall of the PHC pile and the outer wall of the grouting pipe, and injects the slurry of the grouting pipe into the soil at the end of the pile through a pipe body with a grouting hole. The main deficiencies of the patent are:

[0009] (1) This technology places extremely high demands on the performance of the grouting plug, and it is very easy for the slurry to flow out along the side of the grouting plug; (2) Grouting observation requires two sets of pressure equipment, one for pressure grouting and one for maintaining the pressure of the grouting plug, which has high implementation costs and high implementation control requirements; (3) There is no slurry check structure. After the grouting is completed and the pressure of the grouting plug is released, the injected slurry is easy to flow back from the soil to the inside of the PHC pile, resulting in poor grouting reinforcement effect; (4) The grouting holes lack a reliable plugging protection structure, and it is very easy to cause plugging during the pile driving process, resulting in grouting failure.

[0010] In summary, the current conventional grouting devices generally have the disadvantages of complex structure, lack of grouting pipe docking device, difficulty in grouting pipe docking, lack of reliable grouting hole protection structure, poor grouting reinforcement effect, high implementation cost, and high requirements for implementation control. The grouting pile heads of hollow piles currently used in the market all have various usage defects. Therefore, the field lacks a grouting device and method that integrates the advantages of simple processing, convenient docking, convenient construction, fast construction, not easy to block pipes, not easy to block grouting holes, and no slurry backflow. Summary of the invention

[0011] The purpose of the present invention is to propose a new pile bottom grouting system and pile bottom grouting method based on hollow piles according to the deficiencies of the above-mentioned technologies. The pile bottom grouting is carried out by arranging a movable grouting pipe that can be raised and lowered in the hollow pile and cooperating with the pile bottom slurry relay device on the pile bottom plate, thereby reducing the influence of grouting on the pile pressing construction. At the same time, the grouting pipe is of reliable quality and can be reused. In addition, the grouting holes on the pile bottom plate are equipped with a protective component with a non-return function, which can prevent soil from entering the hollow pile during pile pressing, and the grouting holes can be opened under the pressure of grouting without affecting normal grouting. In order to achieve the above-mentioned technical effects, the technical scheme adopted by the present invention is as follows:

[0012] A pile bottom grouting system based on a hollow pile, wherein the bottom of the hollow pile is sealed and connected to a pile bottom plate.

[0013] The pile bottom plate is provided with a slurry outlet device, the slurry outlet device comprises at least one slurry outlet hole opened on the pile bottom plate, each of the slurry outlet holes is movably connected to a protective component, and the slurry outlet hole is closed by the protective component during the pile pressing stage;

[0014] A slurry relay device is provided on the upper surface of the pile bottom plate, and the slurry relay device includes a slurry relay chamber and a docking device. The slurry relay chamber is communicated with the slurry outlet hole. The docking device is used to be movably connected to a movable grouting pipe that can be raised and lowered in the hollow pile. The slurry injected by the movable grouting pipe passes through the slurry relay chamber to push down the protective component and flow out from the slurry outlet hole.

[0015] Furthermore, the movable grouting pipe is axially lifted and lowered in the hollow pile, and the bottom of the movable grouting pipe is movably connected to the docking device.

[0016] Further, the slurry relay cavity is coaxially arranged in the hollow pile, and the docking device is arranged at the center of the slurry relay cavity;

[0017] A guide device is provided between the movable grouting pipe and the hollow pile, and the guide device is used to axially limit the movable grouting pipe that is lifted and lowered in the hollow pile.

[0018] Furthermore, the guide device is provided with at least one guide ring sleeved on the outer wall of the movable grouting pipe, and a plurality of auxiliary positioning rods are circumferentially provided on the outer wall of the guide ring. The ends of the auxiliary positioning rods are provided with balls or universal wheels that roll with the inner wall of the hollow pile.

[0019] Furthermore, the protection component is provided with a protection cover plate, a vertical connecting rod and a horizontal connecting rod.

[0020] The vertical connecting rod passes through the slurry outlet hole and connects the horizontal connecting rod and the protective cover plate located on the upper and lower sides of the slurry outlet hole. The minimum width of the protective cover plate and the length of the horizontal connecting rod are both greater than the diameter of the slurry outlet hole.

[0021] Furthermore, the protection component is provided with a protection cover plate, a spring, and a connecting rod;

[0022] The connecting rod passes through the slurry outlet hole and is connected to the spring and the protective cover plate located on the upper and lower sides of the slurry outlet hole. The spring is elastically compressed between the top end of the connecting rod and the upper surface of the pile bottom plate. The minimum width of the protective cover plate is greater than the diameter of the slurry outlet hole.

[0023] Furthermore, the protective component is provided with a one-way device, and the slurry passes through the one-way device downward in one direction and performs grouting operations at and near the bottom of the pile base plate.

[0024] Furthermore, the upper surface of the slurry relay chamber is provided with a conical surface with a central hole recessed downward.

[0025] Furthermore, the upper surface of the slurry relay chamber is provided with a conical surface with a central hole protruding upward, and the bottle-mouth-shaped docking device is provided at the center of the top of the conical surface;

[0026] The bottom of the movable grouting pipe is provided with a bell mouth matching the conical surface.

[0027] Furthermore, a conical docking port is provided at the top of the docking device, and a conical docking joint threadedly connected to the conical docking port is provided at the bottom of the movable grouting pipe.

[0028] Furthermore, the movable grouting pipe and the butt joint are connected via a threaded connection, a mechanical snap or a necked joint.

[0029] Furthermore, the movable grouting pipe and / or the docking device is provided with a grouting one-way valve.

[0030] Furthermore, after the grouting pressure reaches the set value, the slurry flows out from the slurry outlet hole.

[0031] Further, the pile bottom plate is fixedly connected to the lower end surface of the hollow pile, and the slurry relay device is located on the upper surface of the pile bottom plate; or,

[0032] The slurry relay device is installed on the lower end surface of the hollow pile, and a pile bottom plate is provided on the lower end surface of the slurry relay device. The slurry relay device is in a cone shape with a decreasing diameter from top to bottom.

[0033] Furthermore, a pile tip is fixed on the lower surface of the pile bottom plate, and a protective rib is arranged at a position of the pile tip close to the protective member;

[0034] The pile tip is one or a combination of a conical shape, a square cone shape, a cylindrical shape, a cross shape, and a cross-conical pile tip.

[0035] A pile bottom grouting method based on the above-mentioned pile bottom grouting system based on hollow piles comprises the following steps:

[0036] S1, pressing the hollow pile with a slurry relay device installed in the bottom of the pile to the designed depth;

[0037] S2, lowering the movable grouting pipe through the middle cavity of the hollow pile and docking it with the docking device;

[0038] S3, the slurry in the movable grouting pipe is continuously injected into the slurry relay device and pushes the protective component downward, and the slurry flows out through the slurry outlet hole to the soil around the pile bottom plate;

[0039] S4, after the pile bottom grouting is completed, the grouting is stopped, and the connection between the movable grouting pipe and the docking device is released;

[0040] S5, taking out the movable grouting pipe from the middle cavity of the hollow pile, and continuing the grouting construction of the next pile.

[0041] Since the present invention adopts the above technical solution, its advantages are:

[0042] (1) Grouting at the bottom of the pile can effectively improve the bearing capacity of the hollow pile, thereby improving the safety of the project and saving materials and project capital investment;

[0043] (2) The slurry relay device is pressed into the soil together with the hollow pile, and then grouting is carried out. Grouting at the bottom of the pile does not affect the construction of the hollow pile. Grouting can be carried out after the construction of the pile is completed, thereby improving the efficiency of the hollow pile construction.

[0044] (3) The movable grouting pipe can be reused, saving materials and reducing project capital investment;

[0045] (4) During the pile driving stage, the protective component closes the grouting hole to prevent soil from entering the hollow pile. At the same time, the grout injected under high pressure can push open the protective component and then open the grouting hole without affecting the grouting;

[0046] (5) The movable grouting pipe and slurry relay device can be equipped with a one-way valve to prevent slurry backflow, improve the grouting effect, and save grouting materials;

[0047] (6) The structural design is highly reliable and easy to implement, which is conducive to large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0049] Figure 1 It is a schematic cross-sectional view of the structure of Embodiment 1 of the present invention;

[0050] Figure 2 It is a schematic bottom view of the structure of Embodiment 1 of the present invention;

[0051] Figure 3 This is a schematic diagram of a protective component according to an embodiment of the present invention;

[0052] Figure 4 This is a schematic diagram of the auxiliary positioning rod and universal wheel structure of Embodiment 1 of the present invention;

[0053] Figure 5 This is a schematic cross-sectional view of the structure of Embodiment 2 of the present invention;

[0054] Figure 6 This is a schematic bottom view of the structure of the second embodiment of the present invention;

[0055] Figure 7 This is a schematic cross-sectional view of the structure of Embodiment 3 of the present invention;

[0056] Figure 8 A schematic diagram of a protective cover plate and a limiting ring thereof according to a third structure of an embodiment of the present invention;

[0057] Fig. 9 This is a schematic cross-sectional view of the structure of Embodiment 4 of the present invention;

[0058] Fig.10 This is a schematic cross-sectional view of the structure of Embodiment 5 of the present invention;

[0059] Fig.11 This is a schematic bottom view of the structure of Embodiment 5 of the present invention;

[0060] Fig.12 This is a schematic cross-sectional view of the structure of Embodiment 6 of the present invention;

[0061] Fig.13 It is a schematic bottom view of the structure of embodiment 6 of the present invention.

[0062] Description of figure markings:

[0063] Hollow pile 1, movable grouting pipe 2, slurry relay device 3, pile bottom plate 4, slurry outlet device 5, pile tip 6, auxiliary positioning rod 2.1, universal wheel 2.2, auxiliary docking joint 2.3, docking device 3.1, slurry relay chamber 3.2, slurry inlet one-way valve 3.3, slurry outlet hole 5.1, protection member 5.2, spring 5.3, connecting rod 5.4, one-way device 5.5, protection rib 6.1, protection cover plate 5.21, vertical connecting rod 5.22, horizontal connecting rod 5.23, limit ring 5.24. DETAILED DESCRIPTION

[0064] In the following description, a large number of specific details are provided to provide a more thorough understanding of the present invention. However, it is apparent to those skilled in the art that the present invention can be implemented without one or more of these details. In other examples, in order to avoid confusion with the present invention, some technical features well known in the art are not described.

[0065] In order to fully understand the present invention, detailed steps and detailed structures will be proposed in the following description to illustrate the technical solution of the present invention. The preferred embodiments of the present invention are described in detail below, but in addition to these detailed descriptions, the present invention may also have other implementations.

[0066] Reference Figure 1 As shown, the present invention provides a hollow pile bottom grouting system, wherein the bottom of the hollow pile 1 is sealed and connected to a pile bottom plate 4 .

[0067] The pile bottom plate 4 is provided with a slurry outlet device 5, which includes at least one slurry outlet hole 5.1 opened on the pile bottom plate 4, each slurry outlet hole 5.1 is movably connected with a protective component 5.2, and the slurry outlet hole 5.1 is closed by the protective component 5.2 during the pile pressing stage.

[0068] A slurry relay device 3 is provided on the upper surface of the pile bottom plate 4. The slurry relay device 3 includes a slurry relay chamber 3.2 and a docking device 3.1. The slurry relay chamber 3.2 is communicated with the slurry outlet hole 5.1. The docking device 3.1 is used for movably sealingly connecting with the movable grouting pipe 2. The slurry injected by the movable grouting pipe 2 passes through the slurry relay chamber 3.2 and pushes down the protective component 5.2 to perform grouting operation on the soil around the pile bottom plate 4.

[0069] The movable grouting pipe can be moved up and down as needed, and the end is provided with one or more combinations of a neck joint, a straight thread, a tapered thread, and a mechanical buckle, which can be connected and disconnected with the slurry relay device. The movable grouting pipe can be provided with an auxiliary connection positioning device.

[0070] The advantage of using the protective component 5.2 in the present invention is that: in the pile driving stage, the protective component 5.2 closes the grouting hole 5.1 to prevent soil from entering the grouting hole from the outside; in the grouting stage, the high-pressure slurry can push open or destroy the protective component 5.2, thereby opening the grouting hole 5.1 to achieve normal grouting.

[0071] The advantages of adopting a liftable movable grouting pipe 2 in the present invention are: 1) Since the pile driving construction needs to be implemented in multiple sections, the fixed grouting pipe must be connected when the piles in different sections are connected, which affects the efficiency of the pile driving construction. The movable grouting pipe can be lowered from the pile hole for grouting after all the pile driving is completed; 2) The movable grouting pipe can be reused, and the fixed grouting pipe needs to be installed one for each pile, so the material of the movable grouting pipe is saved; 3) The movable grouting pipe can be lowered for grouting after the pile driving construction, which avoids the risk of damaging the grouting pipe during the pile driving construction and makes the grouting success rate more reliable.

[0072] The advantages of the slurry relay device 3 used in the present invention are: 1) the relay device can realize grouting of multiple slurry outlets of one grouting pipe, which removes the position restriction of the grouting pipe on the slurry outlet, and can arrange a variety of slurry outlets to meet various requirements, while greatly avoiding the situation of grouting failure caused by the blockage of a single grouting hole, greatly improving the grouting success rate; 2) the relay device can greatly improve the grouting pipe docking success rate, connection reliability, docking sealing effect, and improve the grouting success rate and implementation effect; 3) after adding the slurry relay device, the slurry applicability of the grouting device is improved, which can be applied to the situation where there are certain particles and slurry with high viscosity, and the grouting application range is wider. The main body of the slurry relay device 3 is a cylinder, and the top of the cylinder is a flat or conical shape.

[0073] Embodiment 1

[0074] Reference Figure 1-Figure 4 As shown, the grouting device of the embodiment of the present invention includes a hollow pile 1, a movable grouting pipe 2, a slurry relay device 3, a pile bottom plate 4, and a slurry discharge device 5.

[0075] The hollow pile 1 is a PHC prestressed pipe pile, and the pile end is fixedly connected to the pile bottom plate 4 by welding or bolting.

[0076] The pile bottom plate 4 is made of steel, and its outer diameter is the same as that of the hollow pile 1. Four slurry outlet devices 5 are arranged in the hollow area of ​​the hollow pile 1. A cross-shaped pile tip 6 is arranged under the pile bottom plate 4, and a cross-shaped protective rib 6.1 is arranged near the protective member 5.2 to enhance the strength of the cross-shaped pile tip 6, and at the same time, it is more resistant to the impact of the high-pressure slurry rushing out of the slurry outlet hole 5.1. The movable grouting pipe 2 is made of steel pipe material, and the upper part is connected to the pressure grouting system. Eight auxiliary positioning rods 2.1 with universal wheels 2.2 are arranged in two layers near the lower part of the grouting pipe, so that the movable grouting pipe 2 can always remain in the center position of the hollow pile 1 when it moves up and down in the hollow pile 1, so that the movable grouting pipe 2 can be more accurately connected to the docking device 3.1 of the slurry relay device 3 when it descends. In this embodiment, the end of the movable grouting pipe 2 adopts a combination of a necked conical joint and a straight thread.

[0077] The slurry relay device 3 comprises a docking device 3.1, a slurry relay chamber 3.2 and a slurry inlet check valve 3.3. The slurry relay device 3 is located in the cavity area of ​​the hollow pile 1, and the lower end of the outer wall is connected to the pile bottom plate 4 by welding to form the slurry relay chamber 3.2.

[0078] The docking device 3.1 is arranged at the top of the slurry relay device and located at the center of the hollow pile 1. It is made of steel pipe material and has a straight thread inside the upper end. It can be mechanically connected to the movable grouting pipe 2 by rotation. The lower end is connected to the slurry inlet one-way valve 3.3, so that the slurry can only enter the slurry relay cavity 3.2 from the movable grouting pipe 2 and cannot flow in the reverse direction.

[0079] The slurry outlet device 5 includes a slurry outlet hole 5.1 and a protective member 5.2. A plurality of slurry outlet holes 5.1 are provided on the pile bottom plate 4, which are used to connect the slurry relay chamber 3.2 and the soil below the pile bottom plate 4. The protective member 5.2 includes a protective cover plate 5.21, a vertical connecting rod 5.22, and a horizontal connecting rod 5.23, and the protective cover plate 5.21, the vertical connecting rod 5.22, and the horizontal connecting rod 5.23 are all made of steel to ensure strength. One end of the vertical connecting rod 5.22 is welded or mechanically connected to the center of the protection cover plate 5.21, and the other end is welded or mechanically connected to the center of the transverse connecting rod 5.23. The length of the vertical connecting rod 5.22 is greater than the thickness of the pile bottom plate 4 by 0.1mm-100mm, the length of the transverse connecting rod 5.23 is greater than the diameter of the slurry outlet hole 5.1 by 0.1mm-200mm, and the side length of the protective cover plate 5.21 is greater than the diameter of the slurry outlet hole 5.1 by 0.1mm-200mm, so that the protective component is limited at the slurry outlet hole to prevent soil from entering the slurry outlet hole from the outside, while the slurry can flow out of the slurry outlet hole under the action of grouting pressure.

[0080] In addition, at the beginning of the design of the protection component 5.2, by calculating the local strength of the vertical connecting rod 5.22 or the protection cover plate 5.21, it can be achieved that when the slurry pressure at the slurry outlet is greater than 0.3 MPa or above, the protection cover plate 5.21 is destroyed, or the vertical connecting rod 5.22 is broken, or the vertical connecting rod 5.22 is separated from the protection cover plate 5.21 / horizontal connecting rod 5.23, thereby achieving the effect of opening the slurry outlet hole 5.1.

[0081] Embodiment 1 The specific implementation process of hollow pile bottom grouting is as follows:

[0082] (1) The pile bottom grouting device is pressed into the hollow pile 1 to the designed depth. During the pile pressing process, the cross-shaped pile tip 6 can pierce the ground to better press the hollow pile 1 into the soil. In addition, due to the presence of the protective member 5.2, the protective member 5.2 plays a role in closing the grout outlet hole 5.1 during the pile pressing process, preventing soil from entering the hollow pile 1.

[0083] (2) Lower the movable grouting pipe 2 through the middle cavity of the hollow pile 1 to the depth where the slurry relay device 3 is located, and rotate the movable grouting pipe 2 while lowering it, so that the movable grouting pipe 2 and the docking device 3.1 are docked and connected together by means of threads or rotating buckles.

[0084] (3) Connecting the upper part of the movable grouting pipe 2 to a pressure grouting device, and injecting slurry through the pressure grouting device;

[0085] (4) The slurry is continuously injected into the slurry relay device 3 through the movable grouting pipe 2. When the slurry pressure in the slurry relay chamber 3.2 exceeds a certain value, the protective member 5.2 is pushed open to open the slurry outlet hole 5.1, and the injected slurry flows out through the slurry outlet hole 5.1 to the soil around the pile bottom plate 4;

[0086] (5) When the grout injection volume meets the requirement, stop grouting, rotate the movable grouting pipe 2 in the opposite direction, release the connection with the docking device 3.1, and complete the grouting of the hollow pile 1;

[0087] (6) Take out the movable grouting pipe 2 from the middle cavity of the hollow pile 1 and continue the grouting construction of the next pile.

[0088] Embodiment 2

[0089] The second embodiment of the present invention is similar to the first embodiment, but different from the first embodiment in that:

[0090] Reference Figure 5-Figure 6 As shown, 1. The top of the slurry relay device 3 is arranged as a conical surface with the center concave downward, which plays a guiding role toward the center and facilitates the docking of the movable grouting pipe 2 with the docking device 3.1.

[0091] 2. The slurry discharge device 5 is composed of a slurry discharge hole 5.1, a protective member 5.2, a spring 5.3, and a connecting rod 5.4. The protective member 5.2 is composed of a protective cover plate 5.21. The side length of the protective cover plate 5.21 is greater than the diameter of the slurry discharge hole 5.1 by 0.1mm-200mm. One end of the connecting rod 5.4 is connected to the center of the protective member 5.2, and the other end is connected to the upper end of the spring 5.3. The lower end of the spring 5.3 is connected to the upper part of the pile bottom plate 4 or the bottom of the slurry relay device 3. In the pile pressing stage, the spring 5.3 is in a compressed state, and the protective cover plate 5.21 in a natural state closes the slurry discharge hole 5.1. When there is grouting pressure, the slurry discharge hole 5.1 is opened, so that the slurry can only flow out from the slurry relay cavity 3.2 through the slurry discharge hole 5.1, and cannot flow in the reverse direction.

[0092] 3. The auxiliary positioning rod 2.1, the steering wheel 2.2, the slurry inlet one-way valve 3.3 and the protective rib 6.1 are cancelled.

[0093] The purpose of this example is to improve the efficiency of connecting the movable grouting pipe, simplify the structure of the grouting device, and reduce the cost of the grouting device.

[0094] Embodiment 3

[0095] Reference Figure 7-8 As shown, as the third embodiment of the present invention, it is similar to the second embodiment, and the difference from the second embodiment is that:

[0096] 1. The top of the slurry relay device 3 is configured as a conical surface structure protruding upward, and the docking device 3.1 protrudes from the top of the slurry relay device 3.

[0097] 2. The movable grouting pipe 2 is provided with a conical auxiliary docking joint 2.3 that matches the protruding conical surface on the slurry relay device 3, thereby improving the docking efficiency between the movable grouting pipe 2 and the docking device 3.1.

[0098] 3. The slurry discharge device 5 is composed of a slurry discharge hole 5.1, a protective member 5.2, and a one-way device 5.5. The protective member 5.2 is composed of a protective cover plate 5.21 and a limiting ring 5.24. The side length of the protective cover plate 5.21 is greater than the diameter of the slurry discharge hole 5.1 by 0.1mm-200mm. The protective cover plate 5.21 is provided with a limiting ring 5.24 near the slurry discharge hole 5.1. The protective cover plate 5.21 and the limiting ring 5.24 are fixedly connected. The diameter of the limiting ring is less than the diameter of the slurry discharge hole 5.1 by 0.1mm-50mm. The one-way device 5.5 is arranged on the upper part of the slurry discharge hole 5.1 and is installed on the pile bottom plate 4 through the limiting ring 5.24. The one-way device 5.5 has a non-return function, which only allows the slurry to flow from the slurry relay chamber 3.2 to the slurry discharge hole 5.1, and cannot flow in the reverse direction. It is fixedly connected to the upper part of the pile bottom plate 4 or the bottom of the slurry relay device 3 by welding or mechanical connection.

[0099] The purpose of this example is to further improve the efficiency of connecting the movable grouting pipe, improve the reliability of grouting backflow prevention, and improve the grouting effect at the bottom of the pile.

[0100] Embodiment 4

[0101] Reference Fig. 9 As shown, as the fourth embodiment of the present invention, it is similar to the second embodiment, and the difference from the second embodiment is that:

[0102] 1. The end of the movable grouting pipe 2 adopts a tapered thread, and the upper end of the docking device 3.1 is internally provided with a tapered thread, which can be mechanically connected to the movable grouting pipe 2 by rotation; the movable grouting pipe 2 is increased with 4 auxiliary positioning rods 2.1 with steering wheels 2.2, so as to improve the docking efficiency between the movable grouting pipe 2 and the docking device 3.1.

[0103] 2. The slurry relay device 3 is provided with a slurry inlet check valve 3.3, which is connected to the lower end of the connector 3.1.

[0104] 3. The protective cover plate 5.21 adopts a conical structure with the center protruding downward.

[0105] The purpose of this example is to further improve the efficiency of connecting the movable grouting pipes, improve the reliability of grouting backflow prevention, improve the grouting effect at the bottom of the pile, and improve the protective effect of the protective components on the grouting holes.

[0106] Embodiment 5

[0107] Reference Figure 10-11 As shown, as the fifth embodiment of the present invention, it is similar to the second embodiment, and the difference from the second embodiment is that:

[0108] 1. The slurry relay device 3 is located as a whole at the lower part of the hollow pile 1. The diameter of the top is the same as that of the hollow pile 1. It is connected to the bottom of the hollow pile 1. The center area of ​​the top is a conical surface with a downward depression in the center.

[0109] 2. The bottom of the outer wall of the slurry relay device 3 is connected to the pile bottom plate 4 to form a slurry relay cavity 3.2. The diameter of the pile bottom plate 4 is less than or equal to that of the hollow pile 1.

[0110] 3. The pile tip 6 and the slurry relay device 3 together form a conical outer contour surface at the lower part of the hollow pile 1.

[0111] The purpose of this example is to further improve the docking efficiency of the movable grouting pipe, reduce the pile end pressure resistance, and improve the applicability to hollow piles with smaller cavities.

[0112] Embodiment 6

[0113] Reference Figure 12-13 As shown, as the sixth embodiment of the present invention, it is similar to the second embodiment, and the difference from the second embodiment is that:

[0114] 1. The top of the slurry relay device 3 extends a certain length from the side wall, thereby reducing the volume of the slurry relay chamber 2.

[0115] 2. Four auxiliary positioning rods 2.1 with steering wheels 2.2 are added to improve the docking efficiency between the movable grouting pipe 2 and the docking device 3.1.

[0116] 3. A circular pile tip 6 is used, and only one slurry discharge device 5 is provided.

[0117] 4. The slurry relay device 3 is provided with a slurry inlet one-way valve 3.3.

[0118] The purpose of this example is to further improve the efficiency of the joint connection of the movable grouting pipe, reduce the pile end pressure resistance, improve the applicability to hollow piles with smaller cavities, and reduce the production cost of the slurry relay device.

[0119] The above describes the preferred embodiments of the present invention. It should be understood that the present invention is not limited to the above-mentioned specific embodiments, and the devices and structures that are not described in detail should be understood to be implemented in a common manner in the art; any technician familiar with the art can use the above-disclosed methods and technical contents to make many possible changes and modifications to the technical solutions of the present invention without departing from the scope of the technical solutions of the present invention, or modify them into equivalent embodiments of equivalent changes, which does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention are still within the scope of protection of the technical solutions of the present invention.

Claims

1. A pile bottom grouting system based on a hollow pile, wherein a pile bottom plate (4) is provided at the bottom of the hollow pile (1), characterized in that: The pile bottom plate (4) is provided with a slurry discharge device (5), the slurry discharge device (5) comprising at least one slurry discharge hole (5.1) opened on the pile bottom plate (4), each slurry discharge hole (5.1) being movably connected to a protective component (5.2), and the slurry discharge hole (5.1) is closed by the protective component (5.2) during the pile pressing stage; A slurry relay device (3) is provided on the upper surface of the pile bottom plate (4), the slurry relay device (3) comprising a slurry relay chamber (3.2) and a docking device (3.1), the slurry relay chamber (3.2) being connected to the slurry outlet hole (5.1), the docking device (3.1) being used to be connected to a movable grouting pipe (2) in the hollow pile (1), a guide device being provided between the movable grouting pipe (2) and the hollow pile (1), the slurry injected by the movable grouting pipe (2) passing through the slurry relay chamber (3.2) pushes the protective component (5.2) downward and flows out from the slurry outlet hole; The movable grouting pipe (2) is axially lifted and lowered in the hollow pile (1), and the bottom of the movable grouting pipe (2) is movably connected to the docking device (3.1); The protection member (5.2) is provided with a protection cover plate (5.21), a vertical connecting rod (5.22), and a horizontal connecting rod (5.23); the vertical connecting rod (5.22) passes through the pulp outlet hole (5.1) and is connected to the horizontal connecting rod (5.23) and the protection cover plate (5.21) located at the upper and lower sides of the pulp outlet hole (5.1). or The protection component (5.2) is provided with a protection cover plate (5.21), a spring (5.3), and a connecting rod (5.4); the connecting rod (5.4) passes through the slurry outlet hole (5.1) and is connected to the spring (5.3) and the protection cover plate (5.21) located at the upper and lower sides of the slurry outlet hole (5.1); the spring (5.3) is elastically compressed and located between the top end of the connecting rod (5.4) and the upper surface of the pile bottom plate (4); or The protection component (5.2) is composed of a protection cover plate (5.21) and a limiting ring (5.24). The limiting ring (5.24) is arranged on the side of the protection cover plate (5.21) close to the slurry outlet hole (5.1). The protection cover plate (5.21) and the limiting ring (5.24) are fixedly connected.

2. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: The movable grouting pipe (2) is axially lifted and lowered in the hollow pile (1), and the bottom of the movable grouting pipe (2) is movably connected to the docking device (3.1).

3. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: The upper surface of the slurry relay cavity (3.2) is provided with a conical surface which is recessed downward from the center hole, and the docking device (3.1) is arranged in the center hole.

4. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: The upper surface of the slurry relay chamber (3.2) is provided with a conical surface with a central hole protruding upward, and the bottle-mouth-shaped docking device (3.1) is provided at the center of the top of the conical surface; The bottom of the movable grouting pipe (2) is provided with a bell mouth matching the conical surface.

5. The pile bottom grouting system based on hollow piles according to claim 4, characterized in that: The top of the butt joint (3.1) is provided with a conical butt joint, and the bottom of the movable grouting pipe (2) is provided with a conical butt joint threadedly connected to the conical butt joint.

6. The pile bottom grouting system based on hollow piles according to claim 2, characterized in that: The movable grouting pipe (2) and the butt joint (3.1) are connected via a threaded connection, a mechanical buckle or a necked joint.

7. The pile bottom grouting system based on hollow piles according to claim 2, characterized in that: The guide device is used to axially limit the movable grouting pipe (2) that is lifted and lowered in the hollow pile (1); the guide device is provided with at least one guide ring sleeved on the outer wall of the movable grouting pipe (2), the outer wall of the guide ring is circumferentially provided with a plurality of auxiliary positioning rods (2.1), and the ends of the auxiliary positioning rods (2.1) are provided with balls or universal wheels (2.2) that roll with the inner wall of the hollow pile (1).

8. The pile bottom grouting system based on hollow piles according to claim 7, characterized in that: The minimum width of the protective cover plate (5.21) and the length of the transverse connecting rod (5.23) are both greater than the diameter of the pulp outlet hole (5.1).

9. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: The minimum width of the protective cover plate (5.21) is greater than the diameter of the pulp outlet hole (5.1).

10. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: After the grouting pressure reaches the set value, the slurry flows out from the outlet hole.

11. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: The protective component (5.2) is provided with a one-way device (5.5), and the slurry flows out from the slurry outlet hole in one direction to the surrounding soil.

12. The hollow pile-based pile bottom grouting system according to claim 1, characterized in that: The movable grouting pipe (2) and / or the docking device (3.1) is provided with a grouting one-way valve (3.3).

13. The pile bottom grouting system based on hollow piles according to claim 1, characterized in that: The pile bottom plate (4) is fixedly connected to the lower end surface of the hollow pile (1), and the slurry relay device (3) is located on the upper surface of the pile bottom plate (4); or, The slurry relay device (3) is installed on the lower end surface of the hollow pile (1), and a pile bottom plate (4) is provided on the lower end surface of the slurry relay device (3). The slurry relay device (3) is in a conical shape with a decreasing diameter from top to bottom.

14. The pile bottom grouting system based on hollow piles according to claim 13, characterized in that: A pile tip (6) is fixed on the lower surface of the pile bottom plate (4), and a protective rib (6.1) is provided at a position of the pile tip (6) close to the protective component (5.2); The pile tip (6) is in the shape of a cone, a square cone, a cylinder, a cross, or a combination of one or more of a cross-cone pile tip.

15. A pile bottom grouting method based on the pile bottom grouting system based on a hollow pile according to any one of claims 1 to 14, characterized in that: The steps include: S1, pressing the hollow pile (1) with a slurry relay device (3) installed at the bottom of the pile into the designed depth; S2, lowering the movable grouting pipe (2) through the middle cavity of the hollow pile (1) and docking it with the docking device (3.1); S3, the slurry in the movable grouting pipe (2) is continuously injected into the slurry relay device (3) and pushes the protective component (5.2) downward, and the slurry flows out through the slurry outlet hole (5.1) to the soil around the pile bottom plate (4); S4, after the pile bottom grouting is completed, the grouting is stopped, and the connection between the movable grouting pipe (2) and the docking device (3.1) is released; S5, taking out the movable grouting pipe (2) from the middle cavity of the hollow pile (1), and continuing the grouting construction of the next pile.

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