Pile bottom side bag grouting device based on hollow pile and pile bottom side grouting method

Abstract

The present invention provides a pile bottom side bag grouting device based on a hollow pile and a pile bottom side grouting method, wherein a slurry relay device and a pile bottom plate are sequentially arranged at the bottom of the hollow pile from top to bottom; the slurry relay device is provided with a relay cavity, the outer wall of the relay cavity is provided with a slurry outlet hole, the relay cavity is provided with a docking device, the docking device is used for active sealing connection with a movable grouting pipe, a bag structure is fixed on the outer side of the slurry relay device, the bag structure is provided with a grouting bag, the grouting bag is communicated with the grouting hole, and the slurry injected by the movable grouting pipe is opened through the relay cavity to form an expanded bottom part at the side of the pile bottom. The present invention performs grouting by cooperating with the movable grouting pipe and the slurry relay device, thereby reducing the influence of grouting on pile pressing construction, and the grouting pipe can be reused; the outer wall of the slurry relay device is provided with a bag structure, which effectively controls the disordered diffusion and final form of the slurry in the soil, saves grouting materials, gives full play to the pile-soil joint effect, and improves the bearing capacity.

Description

Technical Field

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

[0002] Hollow piles can bear 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 include prefabricated 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 give full play to the pile-soil interaction due to construction or soil layer reasons, and the bearing capacity of a single pile is often far lower than the bearing capacity of the pile body. The main reason is that the soil strength on the pile side and pile end is insufficient, which cannot provide sufficient pile side friction resistance and pile end resistance. In order to effectively solve the above problems, the pile side and pile end grouting technology for hollow piles is constantly developing, but the current hollow pile grouting technology has the following disadvantages:

[0004] 1) Grouting on the pile side requires setting up a grouting channel on the pile body in advance, which increases the pile-making process and affects the strength of the pile body to a certain extent;

[0005] 2) Grouting at the bottom of the pile often lacks anti-return measures, and the grouting liquid flows back after the grouting is stopped, which affects the grouting effect to a certain extent;

[0006] 3) The flow of slurry is uncontrollable after it flows out, resulting in an increase in the grouting volume and unpredictable grouting effect;

[0007] 4) Grouting pipes cannot be reused and have high usage costs. Pre-buried grouting pipes are prone to local leakage, damage, etc. and are difficult to replace.

[0008] Due to the above-mentioned complex production process, great construction difficulty, high cost and difficult to ensure the effect, the existing hollow pile grouting technology is difficult to promote and apply on a large scale.

[0009] Chinese patent application number 201810340103.0 discloses a post-grouting pile head and a post-grouting construction method, in which the upper and lower parts of the pile head are connected by means of a buckle, and cement slurry is injected into the soil through the grouting hole at the pile head, thereby completing the post-grouting construction of the pile end. The shortcomings of this invention are as follows:

[0010] 1) The upper grouting pipe must be constructed during the entire pile driving process, and the grouting pipe cannot be recycled, which has a high cost of use; 2) There is a lack of slurry storage space and slurry backflow prevention measures at the slurry outlet of the pile head, the slurry is easy to flow back, and the grouting efficiency is low; 3) There is no bag structure at the bottom of the pile, the slurry cannot be controlled after flowing out, the grouting effect is not obvious, and it is easy to waste grouting materials, increasing the implementation cost. Summary of the invention

[0011] The purpose of the present invention is to address the deficiencies of the above-mentioned technologies and to propose a pile bottom side bag grouting device based on a hollow pile and a pile bottom side grouting method. By providing a movable grouting pipe, the damage to the grouting pipe caused by the pile pressing process can be effectively avoided, and the reuse of the grouting pipe can be achieved. By providing a grouting device with a non-return function, the slurry can be effectively prevented from flowing back; the grouting bag provided on the side wall of the relay cavity effectively controls the flow range and final shape of the slurry, and forms the effect of an enlarged head at the bottom of the pile after the pile is formed, fully realizing the pile-soil interaction and further improving the grouting effect. In order to achieve the above-mentioned technical effects, the technical scheme adopted by the present invention is as follows:

[0012] A bag grouting device for the side of a pile bottom based on a hollow pile, wherein a slurry relay device and a pile bottom plate are sequentially arranged at the bottom of the hollow pile from top to bottom;

[0013] The slurry relay device is provided with a relay cavity, the outer wall of the relay cavity is provided with a slurry outlet hole, the top of the relay cavity is provided with an opening and a docking device is provided at the opening, and the docking device is used to connect with the movable grouting pipe in the hollow pile.

[0014] A bag structure is fixed on the outside of the slurry relay device, and the bag structure is provided with a grouting bag. The grouting bag is communicated with the grouting hole. The slurry injected by the movable grouting pipe passes through the relay cavity to expand the grouting bag to form an expanded bottom part on the side of the pile bottom.

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

[0016] The relay cavity is coaxially arranged in the hollow pile, and the docking device is arranged at the center of the relay cavity. An auxiliary positioning device is arranged between the movable grouting pipe and the hollow pile.

[0017] Furthermore, the movable grouting pipe and the butt joint are connected via a threaded connection, a mechanical snap or a necked joint.

[0018] Furthermore, the movable grouting pipe and / or the docking device is provided with a one-way check valve.

[0019] Furthermore, the upper surface of the docking device is provided with a conical surface with a center hole recessed downward.

[0020] The bottom end of the movable grouting pipe is provided with a tapered head which is wide at the top and narrow at the bottom.

[0021] Furthermore, a slurry outlet channel communicating with the slurry outlet hole is provided in the relay chamber, and the slurry outlet channel is equipped with a one-way check valve.

[0022] Furthermore, an elastic device is arranged at the slurry outlet, and the slurry outlet is opened when the grouting pressure in the relay cavity reaches the upper limit of the pressure that the elastic device can withstand, otherwise the slurry outlet is closed; or,

[0023] The slurry outlet is provided with a one-way check valve.

[0024] Furthermore, the bag structure includes a bag locking piece, and the bag locking piece is used to seal and fix the grouting bag to the outside of the slurry relay device.

[0025] Furthermore, a baffle is provided on the outer side of the grouting bag, and one end of the baffle is swingably connected to the bag locking piece.

[0026] A pile bottom bag grouting method based on the pile bottom side bag grouting device of the hollow pile comprises the following steps:

[0027] S1, pressing the hollow pile connected with the slurry relay device and the pile bottom plate at the pile bottom to the designed depth;

[0028] S2, lowering the movable grouting pipe through the middle cavity of the hollow pile and docking it with the docking device;

[0029] S3, grouting is continuously performed through the movable grouting pipe, and the grout enters the grouting bag through the grouting relay device to expand it to form an expanded structure located at the side of the pile bottom;

[0030] S4, after the grouting of the pile bottom side is completed, the grouting is stopped, and the connection between the movable grouting pipe and the docking device is released;

[0031] S5, taking out the movable grouting pipe from the middle cavity of the hollow pile, and continuing the grouting construction of the next hollow pile.

[0032] Since the present invention adopts the above technical solution, its advantages are:

[0033] (1) The grouting process does not affect the construction of hollow pile driving. Grouting can be carried out after the driving pile construction is completed, thereby improving the efficiency of hollow pile construction.

[0034] (2) Through the relay device, grouting can be achieved in multiple grouting holes of one grouting pipe, eliminating the position restriction of the grouting pipe on the grouting hole. Various grouting holes can be arranged to meet various requirements. At the same time, the situation of grouting failure caused by blockage of a single grouting hole can be greatly avoided. At the same time, the grouting pipe docking success rate, connection reliability, docking sealing effect can be greatly improved, and the grouting success rate and implementation effect can be improved;

[0035] (3) The setting of the bladder at the side of the pile bottom effectively controls the disordered diffusion and final form of the slurry in the soil around the pile, saves grouting materials, gives full play to the pile-soil interaction, and effectively improves the bearing capacity;

[0036] (4) During the pile pressing process before grouting, the bag is in a contracted state, reducing the contact area with the soil and is not easily damaged;

[0037] (5) By adopting a grouting bag of a specific shape, the shape of the grouting bag after it is expanded can be controlled. After the grouting bag is expanded by the injected slurry, it can be maintained in the shape we need (such as an ellipse, a semicircle, etc.), thereby further effectively improving the bearing capacity according to different construction environments;

[0038] (6) The check valve is set to prevent slurry backflow, improve grouting effect, and save grouting materials;

[0039] (7) The grouting pipe can be reused, saving materials and reducing project capital investment;

[0040] (8) The structural design is highly reliable and easy to implement, which is conducive to large-scale promotion and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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.

[0042] Figure 1 It is a schematic diagram of a structural cross-section of Embodiment 1 of the present invention;

[0043] Figure 2 It is a schematic diagram of the structural cross-section of the second embodiment of the present invention;

[0044] Figure 3 It is a schematic diagram of the structural cross-section of the third embodiment of the present invention;

[0045] Figure 4 It is a schematic diagram of the structural cross-section of embodiment 4 of the present invention.

[0046] Description of reference numerals:

[0047] Hollow pile 1; movable grouting pipe 2; auxiliary positioning device 2.1; docking device 2.2; slurry relay device 3; docking device 3.1, relay cavity 3.2; one-way check valve 3.3; elastic device 3.4; bag structure 4; grouting bag 4.1; bag locking piece 4.2; baffle 4.3; pile bottom plate 5. DETAILED DESCRIPTION

[0048] 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.

[0049] 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.

[0050] The present invention provides a pile bottom side bag grouting device based on a hollow pile, wherein a slurry relay device 3 and a pile bottom plate 5 are sequentially arranged at the bottom of the hollow pile 1 from top to bottom.

[0051] The slurry relay device 3 is provided with a relay chamber 3.2, the outer wall of the relay chamber 3.2 is provided with a slurry outlet hole, the top of the relay chamber 3.2 is provided with an opening and a docking device 3.1 is provided at the opening, and the docking device 3.1 is used to be movably and sealedly connected with the movable grouting pipe 2 that can be raised and lowered in the hollow pile 1. The movable grouting pipe 2 can move up and down as needed, and the end is provided with a neck joint, a straight thread, a tapered thread, a mechanical buckle or one or more combinations thereof, which can be connected and disconnected with the docking device 3.1.

[0052] A bag structure 4 is fixed to the outside of the slurry relay device 3. The bag structure 4 is provided with a grouting bag 4.1. The grouting bag 4.1 is connected to the grouting hole. The slurry injected by the movable grouting pipe 2 passes through the relay cavity 3.2 to expand the grouting bag 4.1 to form an expanded bottom part on the side of the pile bottom.

[0053] The advantages of the movable grouting pipe 2 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 for each pile, which saves the material of the movable grouting pipe; 3) The movable grouting pipe can be lowered for grouting after the pile driving construction, avoiding the risk of damaging the grouting pipe during the pile driving construction, and the grouting success rate is more reliable.

[0054] The advantages of the slurry relay device 3 are: 1) The relay device can realize grouting of multiple slurry outlet holes of one grouting pipe, which removes the position restriction of the grouting pipe on the slurry outlet hole, and can arrange a variety of slurry outlet holes to meet various requirements. At the same time, it greatly avoids the situation of grouting failure caused by blockage of a single grouting hole, and greatly improves the grouting success rate; 2) The relay device can greatly improve the grouting pipe docking success rate, connection reliability, and docking sealing effect, thereby improving the grouting success rate and implementation effect; 3) After adding the slurry relay device, the slurry applicability of the grouting device is improved, and it can be applied to situations where there are certain particles in the slurry and the slurry has a higher viscosity, and the grouting application range is wider.

[0055] The advantages of the bag structure 4 are: 1) The setting of the bag at the side of the pile bottom effectively controls the disordered diffusion and final form of the slurry in the soil around the pile, saves grouting materials, gives full play to the pile-soil interaction, and effectively improves the bearing capacity. 2) During the pile pressing process before grouting, the bag is in a contracted state, reducing the contact area with the soil and is not easily damaged.

[0056] The pile bottom plate is connected to the slurry relay device, and the lower part can be provided with one or more combinations of conical, square-conical, cylindrical, cross-shaped, and cross-conical pile tips to meet the needs of hollow pile compression.

[0057] Embodiment 1

[0058] A bag grouting device for the pile bottom side based on a hollow pile according to an embodiment of the present invention comprises a hollow pile 1, a movable grouting pipe 2, a slurry relay device 3, a bag structure 4, and a pile bottom plate 5.

[0059] The hollow pile 1 adopts a PHC prestressed pipe pile, the bottom end of the pile is fixedly connected to the slurry relay device 3 by welding or bolting, and the slurry relay device 3 is connected to the pile bottom plate 5 by welding or bolting.

[0060] The movable grouting pipe 2 is made of steel pipe material, the upper part is connected to the pressure grouting equipment, the middle part is provided with an auxiliary positioning device 2.1, and the lower part is provided with a docking device 2.2. Among them, the auxiliary positioning device 2.1 is sleeved on the movable grouting pipe 2, and the end of the auxiliary positioning device 2.1 is provided with a universal wheel and a ball bearing that slides with the inner wall of the hollow pile 1, which plays an axial guiding role. The main function of the auxiliary positioning device 2.1 is to prevent the movable grouting pipe 2 from being eccentric during the lowering process in the hollow pile 1, and to ensure that it is smoothly connected to the lower slurry relay device 3. The end of the docking device 2.2 can be connected to the docking device 3.1 of the slurry relay device by a threaded structure connection method, but not limited to, so that the slurry can be smoothly connected to the slurry relay device 3.

[0061] The slurry relay device 3 includes a docking device 3.1, a relay chamber 3.2, a one-way check valve 3.3 and an elastic device 3.4. The upper end of the slurry relay device 3 is sealed and connected to the hollow pile 1, and the lower end of the slurry relay device 3 is connected to the pile bottom plate 5 by welding to form a relay chamber 3.2. The docking device 3.1 is arranged at the center of the hollow pile 1 at the top of the slurry relay device, and a corresponding connection structure is arranged inside the upper end, which can be mechanically connected to the docking device 2.2 of the movable grouting pipe 2 by rotation. A one-way check valve 3.3 is arranged at the lower end of the docking device 3.1, so that the slurry can only enter the relay chamber 3.2 from the movable grouting pipe 2, and cannot flow in the reverse direction.

[0062] The elastic device 3.4 realizes the function of retaining the slurry in the relay chamber when there is no pressure, and the slurry flows out after reaching a certain pressure, and the function of preventing the slurry from flowing back when the grouting is stopped. The preferred structure of the elastic device 3.4 is as follows: the structure of the elastic device 3.4 includes a spring and a sealing cover plate, which are respectively located on the inner and outer sides of the grouting hole, and the connecting rod passing through the grouting hole connects the spring and the sealing cover plate together. When the grouting pressure in the relay chamber 3.2 is not enough to deform the spring, the sealing cover plate closes the grouting hole under the action of the spring to prevent the slurry in the grouting bag 4.1 from flowing back into the relay chamber 3.2; when the grouting pressure in the relay chamber 3.2 reaches a certain value, the spring is compressed under the action of the pressure and drives the sealing cover plate to move outward to open the grouting hole to connect the relay chamber 3.2 and the grouting bag 4.1. The elastic device 3.4 can also be replaced by a one-way check valve, and the slurry can only flow from the relay chamber 3.2 to the grouting bag 4.1 and cannot flow back.

[0063] The bag structure 4 is provided with a grouting bag 4.1 and a bag locking piece 4.2. The main function of the grouting bag 4.1 is to receive the slurry flowing out of the slurry relay device 3, limit its flow range and form an effective bottom expansion part at the bottom of the pile; the upper and lower parts of the grouting bag 4.1 are provided with bag locking pieces 4.2, and the grouting bag 4.1 is fixed to the outer side of the slurry relay device through the bag locking pieces 4.2 to prevent the slurry from flowing out. When grouting is not performed, the bag structure can be completely received in the gap between the pile bottom plate and the hollow pile 1 to ensure that the pile pressing process is not damaged. A protective device can be provided on the outside of the grouting bag to further prevent the grouting bag from being damaged during the pile pressing process.

[0064] The pile bottom plate 5 is made of steel, and its outer diameter is the same as that of the hollow pile 1, and its top is connected to the bottom of the slurry relay device 3. Different pile head forms can be arranged at the lower part of the pile bottom plate 5 so as to penetrate into the soil smoothly.

[0065] Embodiment 1 The specific implementation process of grouting the bottom side of the hollow pile is as follows:

[0066] (1) The hollow pile 1 connected to the slurry relay device 3 and the pile bottom plate 5 is pressed into the pile to the designed depth.

[0067] (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.

[0068] (3) The upper part of the movable grouting pipe 2 is connected to a pressure grouting device, and slurry is injected by the pressure grouting device.

[0069] (4) The slurry is continuously injected into the slurry relay device 3 through the movable grouting pipe 2. When the slurry pressure in the relay cavity 3.2 exceeds the upper limit of the pressure that the elastic device 3.4 can withstand, the elastic device 3.4 deforms and opens the slurry outlet hole. The slurry enters the side bag structure 4 through the slurry relay device 3. The grouting bag 4.1 is filled with slurry and expands to form an expanded structure located at the side of the pile bottom.

[0070] (5) When the grouting volume meets the requirement, stop grouting, rotate the movable grouting pipe 2 in the reverse direction, release the connection with the docking device 3.1, and complete the grouting of the hollow pile 1.

[0071] (6) The movable grouting pipe 2 is taken out from the middle cavity of the hollow pile 1, and the grouting construction of the next hollow pile 1 is continued.

[0072] Embodiment 2

[0073] The second embodiment of the present invention is similar to the first embodiment, but different from the first embodiment in that:

[0074] (1) The docking device 3.1 at the upper part of the relay cavity 3.2 is configured as a conical inlet to facilitate smooth docking of the upper movable grouting pipe 2 therewith;

[0075] (2) The auxiliary positioning device in the movable grouting pipe 2 is eliminated, the structure is simplified, and the docking efficiency can be further improved.

[0076] (3) It should be noted that the upper docking device of the relay cavity is not fixed in form, including but not limited to threads, rotating buckles, etc., which are not listed here one by one and can be adjusted according to the actual construction and grouting conditions.

[0077] Embodiment 3

[0078] As the third embodiment of the present invention, it is similar to the above embodiment, but the difference is that:

[0079] (1) The one-way check valve 3.3 at the bottom of the relay chamber 3.2 in the first embodiment is eliminated;

[0080] (2) The slurry outlet hole on the side wall of the relay chamber 3.2 is changed into a slurry outlet channel 3.5 and a one-way check valve 3.3 is arranged in the channel to achieve the effect of slurry anti-return. The number of slurry outlet channels 3.5 is set according to the actual grouting amount.

[0081] Embodiment 4

[0082] The fourth embodiment of the present invention is similar to the first embodiment, but different from the first embodiment in that:

[0083] (1) A protective device may be provided on the outside of the grouting bag 4.1 to further prevent the grouting bag from being damaged during the pile driving process. For example, a baffle 4.3 is provided on the outside of the grouting bag 4.1 as a protective device to ensure that the grouting bag 4.1 is not damaged during the pile driving process. The baffle 4.3 can rotate around the bag locking member 4.2. During grouting, as the grouting bag 4.1 expands, the baffle 4.3 is squeezed open, and the grouting bag 4.1 can achieve an expansion effect.

[0084] 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 bag grouting device for the bottom side of a hollow pile, characterized in that: A slurry relay device (3) and a pile bottom plate (5) are provided in sequence from top to bottom at the bottom of the hollow pile (1); The slurry relay device (3) is provided with a relay chamber (3.2), the outer wall of the relay chamber (3.2) is provided with a slurry outlet hole, the top of the relay chamber (3.2) is provided with an opening and a docking device (3.1) is provided at the opening, and the docking device (3.1) is used to connect to the movable grouting pipe (2) in the hollow pile (1). A bag structure (4) is fixed on the outside of the grout relay device (3), the bag structure (4) is provided with a grouting bag (4.1), the grouting bag (4.1) is connected to the grouting hole, and the grout injected by the movable grouting pipe (2) passes through the relay cavity (3.2) to expand the grouting bag (4.1) to form an expanded bottom portion on the side of the pile bottom; 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 detachably connected to the docking device (3.1); An elastic device (3.4) is arranged at the slurry outlet hole, and the slurry outlet hole is opened when the grouting pressure in the relay cavity (3.2) reaches the upper limit of the pressure that the elastic device (3.4) can withstand, and otherwise the slurry outlet hole is closed; or, the slurry outlet hole is arranged with a one-way check valve; The bag structure (4) comprises a bag locking piece (4.2), and the bag locking piece (4.2) seals and fixes the grouting bag (4.1) to the outside of the slurry relay device (3).

2. The bladder grouting device for the bottom side of a hollow pile according to claim 1, characterized in that: An auxiliary positioning device (2.1) is provided between the movable grouting pipe (2) and the hollow pile (1).

3. The bladder grouting device for the bottom side of a hollow pile according to claim 1, 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.

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

5. The bladder grouting device for the bottom side of a hollow pile according to claim 2, characterized in that: The upper surface of the docking device (3.1) is provided with a conical surface with a center hole recessed downward. The bottom end of the movable grouting pipe (2) is provided with a conical head which is wider at the top and narrower at the bottom.

6. The bladder grouting device for the bottom side of a hollow pile according to claim 1, characterized in that: A pulp outlet passage (3.5) communicating with the pulp outlet hole is provided in the relay chamber (3.2), and a one-way check valve is arranged in the pulp outlet passage (3.5).

7. The bladder grouting device for the bottom side of a hollow pile according to claim 1, characterized in that: A baffle (4.3) is provided on the outside of the grouting bag (4.1), and one end of the baffle (4.3) is swingably connected to the bag locking piece (4.2).

8. A pile bottom side grouting method based on the pile bottom side bag grouting device based on the hollow pile according to any one of claims 1 to 7, characterized in that: The steps include: S1, pressing the hollow pile (1) connected to the slurry relay device (3) and the pile bottom plate (5) 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, grouting is continued through the movable grouting pipe (2), and the grout enters the grouting bag (4.1) through the grouting relay device (3) to expand it to form an expanded structure located at the side of the pile bottom; S4, after the grouting of the pile bottom side 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 hollow pile (1).

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