Pile end bottom grouting device, cast-in-place pile and construction method thereof

Abstract

The present invention relates to the field of foundation technology, and specifically to a pile end bottom grouting device, a bored pile, and a construction method thereof, which aims to solve the defect in the prior art that the timing and conditions of rupture of the grouting cavity are difficult to control. The pile end bottom grouting device includes a fixed plate; a slurry storage bag fixed on the fixed plate, the slurry storage bag forms a receiving cavity suitable for accommodating slurry, or the slurry storage bag and the fixed plate enclose a receiving cavity suitable for accommodating slurry, the slurry storage bag has a filled state in which the interior is filled with slurry to support the pile body and a collapsed state in which the interior is hollow, the slurry storage bag is preset with a fixed ultimate bearing strength value, and the volume is fixed in the filled state.

Description

Technical Field

[0001] The present invention relates to the technical field of foundation, and in particular to a pile end bottom grouting device, a cast-in-place pile and a construction method thereof. Background Art

[0002] Currently, in the field of foundations, there are two main types of post-grouting for pile ends: open grouting and closed grouting. Closed grouting often uses steel plate capsule grouting, as described in the invention patent with announcement number CN110896646B, entitled "Pile Bottom Grouting Device and Method of Use, Cast-in-Place Pile Body and Construction Method thereof." The method comprises a grouting capsule, a grouting pipe, and a fixing plate. After the pile is poured, grout is injected into the grouting capsule through the grouting pipe to form an expanded head at the pile bottom. However, the grouting capsule expands with increasing pressure, and its relationship with the grouting pressure and grouting volume, as well as the volume of the expanded head within the closed grouting chamber, are difficult to control. This makes it difficult to control the timing and conditions of rupture of the grouting capsule, which in turn affects the bearing capacity of the pile. Summary of the Invention

[0003] Therefore, the technical problem to be solved by the present invention is to overcome the defect in the prior art that it is difficult to control the timing and conditions of grouting cavity rupture, thereby providing a pile end bottom grouting device, cast-in-place pile and its construction method that can accurately control the timing and conditions of grouting cavity rupture.

[0004] In order to solve the above technical problems, the present invention provides a pile end bottom grouting device, comprising:

[0005] Fixed plate;

[0006] A slurry storage bag is fixed on the fixed plate, the slurry storage bag forms a receiving cavity suitable for accommodating slurry, or the slurry storage bag and the fixed plate form a receiving cavity suitable for accommodating slurry, the slurry storage bag has a filled state in which the interior is filled with slurry to support the pile body and a collapsed state in which the interior is hollow, the slurry storage bag has a preset fixed ultimate pressure strength value and the volume is fixed in the filled state.

[0007] Optionally, the pulp storage bag is made of chemical synthetic fiber cloth or plastic film.

[0008] Optionally, a weak area is provided on the slurry storage bag, and the pressure-bearing strength of the weak area is lower than the pressure-bearing strength of other parts of the slurry storage bag so as to form a slurry discharge area when under pressure.

[0009] Optionally, also include:

[0010] A grouting pipe is connected to the inner cavity of the grout storage bag and is suitable for injecting grout into the grout storage bag;

[0011] The first one-way valve is arranged at the communication position between the grouting pipe and the slurry storage bag, and is suitable for preventing the blockage in the slurry storage bag from entering the grouting pipe.

[0012] Optionally, a first slurry outlet hole is opened on the wall of the grouting pipe, and the first one-way valve includes:

[0013] A first water-stop tape is wound around the portion of the grouting pipe where the first slurry outlet is provided;

[0014] A first rubber sleeve, directly or indirectly sleeved on the outside of the first water-stop tape;

[0015] The first water-stop tape and the first rubber sleeve have a sealed state in which they are tightened toward the grouting pipe, and an open state in which a gap is formed between the first water-stop tape and the first rubber sleeve due to the pressure in the grouting pipe.

[0016] The first hard sheet is sandwiched between the first water-stop tape and the first rubber sleeve and is arranged corresponding to the first slurry outlet hole.

[0017] Optionally, the grouting pipe includes:

[0018] A first pulp outlet portion is located in the inner cavity of the pulp storage bag;

[0019] An interface, passing through the fixing plate and communicating with the first pulp outlet;

[0020] The slurry inlet pipe is sealed and connected to the interface.

[0021] Optionally, the fixing plate is an annular plate, and the slurry storage bag is an annular structure adapted to the annular plate.

[0022] Optionally, the inner ring edge of the fixing plate is provided with an annular stopper extending to the inner ring of the slurry storage bag.

[0023] Optionally, also include:

[0024] a grouting pipe, communicating with the inner area of the annular baffle, and adapted for injecting grout into the pile hole;

[0025] The second one-way valve is provided at the communication position between the grouting pipe and the inner area of the annular baffle, and is suitable for preventing the obstruction in the pile hole from entering the grouting pipe.

[0026] Optionally, a second slurry outlet hole is opened on the wall of the slurry supply pipe, and the second one-way valve includes:

[0027] A second water-stop tape is wound around the portion of the grouting pipe where the second slurry outlet hole is opened;

[0028] A second rubber sleeve is directly or indirectly sleeved on the outside of the second water-stop tape;

[0029] The second water-stop tape and the second rubber sleeve both have a sealed state in which they are tightened toward the grouting pipe, and an open state in which a gap is formed between the grouting pipe and the second rubber sleeve due to the pressure in the grouting pipe;

[0030] The second hard sheet is sandwiched between the second water-stop tape and the second rubber sleeve and is arranged corresponding to the second slurry outlet hole.

[0031] Optionally, the slurry supply pipe has a second slurry outlet portion extending to the inner area of the annular baffle, and the second slurry outlet portion is an annular pipeline extending along the inner wall of the annular baffle.

[0032] Optionally, a detection port is provided on the fixing plate, and the detection port is suitable for filling the medium into the slurry storage bag.

[0033] Optionally, also include:

[0034] The protective cover is detachably connected to the fixing plate and is suitable for being arranged on the outside of the slurry storage bag before construction.

[0035] The present invention also provides a cast-in-place pile, comprising:

[0036] The aforementioned pile end bottom grouting device;

[0037] The steel cage is connected to the fixing plate of the grouting device at the bottom of the pile end.

[0038] The present invention also provides a construction method for the above-mentioned cast-in-place pile, which comprises the following steps in sequence:

[0039] S1. Forming a pile hole, cleaning the sediment in the pile hole;

[0040] S2. The lower end of the pile end bottom grouting device is installed and the steel cage is sunk to the bottom of the pile hole;

[0041] S3 pouring concrete into the pile hole to form a cast-in-place pile;

[0042] S4. Grouting is injected into the grout storage bag to form an enlarged head at the bottom of the pile.

[0043] Optionally, in step S4, control is performed according to the properties of the soil forming the pile hole: if it is sandy soil, the actual grouting volume and grouting pressure are controlled to be greater than the preset value of the slurry storage bag to cause the slurry storage bag to rupture; if it is clay soil, the actual grouting volume and grouting pressure are controlled to be less than the preset value of the slurry storage bag to avoid rupture of the slurry storage bag.

[0044] The technical solution of the present invention has the following advantages:

[0045] 1. The pile end bottom grouting device provided by the present invention replaces the existing grouting capsule with a slurry storage bag. The volume of the slurry storage bag in the filled state is fixed and will not expand with the increase of internal pressure. A fixed ultimate compressive strength value is preset. During actual grouting, if it is required to rupture, the actual grouting volume and grouting pressure are controlled to be greater than the preset value of the slurry storage bag; if it is not required to rupture, the actual grouting volume and grouting pressure are controlled to be less than the preset value of the slurry storage bag. In this way, the timing and conditions of the rupture of the slurry storage bag can be accurately controlled, thereby more accurately grasping the volume and shape of the pile bottom expansion head, controlling the grouting process and effect, and ultimately effectively eliminating pile bottom settlement, greatly improving the ultimate bearing capacity of the bored pile, and reducing the project cost.

[0046] 2. The pile-end bottom grouting device provided by the present invention features a weak area on the grouting bag. The compressive strength of the weak area is lower than that of the rest of the bag. During grouting, the weak area is initially compressed and ruptures, forming a grouting outlet. This allows the weak area to be positioned at different locations on the bag or configured in various shapes to meet the needs of various construction scenarios.

[0047] 3. The pile end bottom grouting device provided by the present invention is designed with a specific one-way valve structure for the case where the slurry outlet is opened on the pipe wall, including a water-stop tape, a hard sheet and a rubber sleeve. When the pressure inside the pipe is greater than the ultimate bearing strength of the water-stop tape, the water-stop tape moves away from the pipe wall under the action of the pressure inside the pipe, so that a slurry outlet gap is formed between the water-stop tape and the pipe wall, and the pressure inside the pipe overcomes the elastic force of the rubber sleeve at the same time, so that it follows the water-stop tape and turns to the open state to complete the slurry outlet; when the pressure inside the pipe is less than or equal to the ultimate bearing strength of the water-stop tape, the pressure inside the pipe is not enough to open the water-stop tape, and the water-stop tape is tightly attached to the pipe wall under the elastic force of the rubber sleeve, and the rubber sleeve turns into a sealed state. In this state, it can prevent the slurry outside the pipe from flowing back into the pipe, thereby playing the role of a one-way valve. In addition, the hard sheet can prevent the rubber sleeve from being partially sucked into the pipe through the slurry outlet due to negative pressure, causing damage to the sealing performance.

[0048] 4. The pile end bottom grouting device provided by the present invention has a fixed plate configured as an annular plate. During the entire process of the device sinking along the pile hole, muddy water and air in the pile hole will pass through the hole and thus enter the top of the pile bottom grouting device, and no vortex that damages the hole wall will be formed between the pile bottom grouting device and the pile hole, thereby effectively avoiding the problem of vortex that damages the hole wall formed in the pile hole due to the inability to discharge muddy water and the like during the descent process, and avoiding the muddy water flow swirling between the edge of the fixed plate and the pile hole from scouring and disturbing the pile hole wall, effectively preventing the pile hole wall collapse, excessive sediment at the bottom of the hole and broken piles, and effectively improving the construction quality and progress of the cast-in-place pile body.

[0049] 5. The bored pile provided by the present invention has the advantages described in any of the above solutions because it has the pile end bottom grouting device described in any of the above solutions.

[0050] 6. The construction method provided by the present invention can determine the actual grouting volume and grouting pressure according to the properties of the soil, combined with the preset capacity and preset ultimate bearing strength of the slurry storage bag, so as to accurately control the timing and conditions of the rupture of the slurry storage bag, and further more accurately control the shape and volume of the expansion head to ensure sufficient bearing capacity. BRIEF DESCRIPTION OF THE DRAWINGS

[0051] In order to more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the specific embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0052] Figure 1 A schematic diagram of an implementation structure of a pile end bottom grouting device according to the present invention;

[0053] Figure 2 A schematic diagram of another embodiment of the pile end bottom grouting device of the present invention;

[0054] Figure 3 It is a top view schematic diagram of the pile end bottom grouting device of the present invention;

[0055] Figure 4 It is a structural schematic diagram of the one-way valve of the present invention;

[0056] Figure 5 It is a structural schematic diagram of the cast-in-place pile of the present invention;

[0057] Figure 6 This is a schematic diagram of the grouting pipe structure of the present invention;

[0058] Figure 7 It is a top view of the polygonal pulp storage bag of the present invention.

[0059] Description of reference numerals:

[0060] 1. Fixed plate; 2. Slurry storage bag; 21. Inspection port; 3. Grouting pipe; 31. First slurry outlet; 311. First slurry outlet hole; 32. Interface; 33. Slurry inlet pipe; 4. First one-way valve; 41. First water-stop tape; 42. First rubber sleeve; 43. First hard sheet; 5. Annular baffle; 6. Grouting pipe; 61. Second slurry outlet; 611. Second slurry outlet hole; 7. Second one-way valve; 71. Second water-stop tape; 72. Second rubber sleeve; 73. Second hard sheet; 8. Steel cage. DETAILED DESCRIPTION

[0061] The technical solution of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0062] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood in a broad sense. For example, they may refer to fixed, detachable, or integral connections; mechanical or electrical connections; direct or indirect connections through an intermediate medium; and internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0063] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0064] The present invention provides a pile end bottom grouting device, referring to Figure 1-Figure 3 , including a fixed plate 1 and a slurry storage bag 2, specifically as follows:

[0065] The fixing plate 1 can be made of metal, high-strength plastic, hard silicone, or other commonly used materials with a hardness that meets the required hardness. The fixing plate 1 can be manufactured using conventional machining or 3D printing. The shape of the fixing plate 1 is not critical and can be determined based on the cross-sectional shape of the pile hole.

[0066] The slurry bag 2 is fixed on the fixed plate 1. The slurry bag 2 forms a receiving cavity suitable for receiving the slurry, or the slurry bag 2 and the fixed plate 1 form a receiving cavity suitable for receiving the slurry. The slurry bag 2 can be a separate whole and then fixed on the fixed plate 1; or it can be an open structure and then sealed with the fixed plate 1 to form a receiving cavity. The slurry bag 2 can be spherical after being filled (such as Figure 2 as shown) or a cuboid (as Figure 1 as shown) or polygonal (as shown) Figure 7As shown) or other common shapes, it is easy for those skilled in the art to determine the shape of the slurry storage bag 2 after filling according to the cross-sectional shape of the pile hole. The slurry storage bag 2 can be a symmetrical structure or an asymmetrical structure. The slurry storage bag 2 can be integrally formed by weaving, textile or blow pressing; or it can be cut and formed by sewing, bonding or other methods. The connection between the slurry storage bag 2 and the fixed plate 1 can be achieved by the following methods: a groove is provided on the edge of the fixed plate 1, a pinhole is provided in the groove, the edge of the slurry storage bag 2 is placed in the groove, and the groove and the pinhole are used to bind the slurry storage bag 2 to the fixed plate 1 by sewing technology; of course, the slurry storage bag 2 and the fixed plate 1 can also be connected by rivets or chemical adhesives or other common connection methods. The slurry storage bag 2 has a filled state in which the interior is filled with slurry to support the pile body and a collapsed state in which the interior is hollow. The slurry storage bag 2 has a preset fixed pressure strength value and a fixed volume in the filled state. The so-called filled state here refers to the state in which the interior of the slurry storage bag 2 is filled with slurry and the surface is stretched tight; the closed state refers to the state in which the interior is not filled with slurry or is not fully filled with slurry, and the surface is not completely stretched tight. "Fixed volume in the filled state" means that the slurry storage bag does not have elastic expansion and contraction, and the volume is fixed after the internal slurry is filled. This is mainly relative to the grouting capsules in the prior art. When the existing grouting capsules are in the filled state, as the internal slurry pressure increases, they will continue to expand. The slurry storage bag 2 in the present invention has a fixed volume in the filled state. "Preset fixed pressure strength value" means that when the slurry storage bag 2 is manufactured, the pressure strength value when it breaks under pressure has been designed, and this value is a fixed value. The existing grouting capsules become larger as the internal slurry pressure increases, and are easily disturbed by the external pile hole wall after expansion. The pressure strength value when it breaks is not a fixed value.

[0067] The pile end bottom grouting device of the present invention adopts a slurry storage bag 2 whose volume remains unchanged in the filled state. The ultimate pressure bearing strength and ultimate volume of the slurry storage bag 2 are fixed and will not change continuously like the existing grouting capsules. Therefore, the actual grouting pressure and grouting amount can be determined according to the preset ultimate volume and ultimate pressure bearing strength of the slurry storage bag 2, thereby accurately controlling the rupture timing and rupture conditions of the slurry storage bag 2.

[0068] Preferably, the slurry storage bag 2 can be made of chemical synthetic fiber fabric, such as polyester, nylon, acrylic, etc.; it can also be made of plastic film, such as polyvinyl chloride, polyethylene, polypropylene, etc. Specifically, the strength of the plastic film and chemical synthetic fiber must be able to meet the requirements of filling concrete slurry, which is the most basic condition known to those skilled in the art. Of course, in other embodiments, the slurry storage bag 2 can also be made of other common materials, but it must be suitable for accommodating concrete slurry and have a fixed volume when filled. Specifically, the slurry storage bag 2 can be a single-layer or multi-layer structure.

[0069] As a further improvement, a weak area is provided on the slurry storage bag 2. The compressive strength of the weak area is lower than that of other parts of the slurry storage bag 2, so that a slurry discharge area is formed when pressure is applied. The weak area can be strip-shaped, circular, or any other shape, which is mainly determined by the form of slurry discharge required.

[0070] The following effects are achieved: the setting of the weak area can more accurately control the specific position of the slurry storage bag 2 where the slurry bursts and in what form the slurry bursts, thereby further improving the controllability of the rupture of the slurry storage bag 2 and meeting the needs of various different construction scenarios.

[0071] Of course, in other embodiments, the pulp storage bag 2 may also be uniform, that is, no weak area is provided.

[0072] As a further improvement plan, refer to Figure 1 and Figure 2 The pile end bottom grouting device also includes:

[0073] The grouting pipe 3 is connected to the inner cavity of the slurry storage bag 2 and is suitable for grouting into the slurry storage bag 2;

[0074] The first one-way valve 4 is provided at the communication position between the grouting pipe 3 and the slurry storage bag 2 , and is suitable for preventing the blockage in the slurry storage bag 2 from entering the grouting pipe 3 .

[0075] The following effects are achieved: the setting of the first one-way valve 4 can ensure the normal output of the slurry, and can also prevent external blockages such as mud, sediment, etc. from entering the grouting pipe 3.

[0076] Preferably, refer to Figure 4 The wall of the grouting pipe 3 is provided with a first slurry outlet 311, and the first one-way valve 4 includes:

[0077] The first water-stop tape 41 is wrapped around the portion of the grouting pipe 3 where the first slurry outlet hole 311 is opened;

[0078] The first rubber sleeve 42 is directly put on the outside of the first water-stop tape 41. The first rubber sleeve 42 can be made of elastic materials such as rubber or soft silicone;

[0079] The first water-stop tape 41 and the first rubber sleeve 42 both have a sealed state in which they are tightened toward the grouting pipe 3, and an open state in which a gap is formed between the first water-stop tape 41 and the grouting pipe 3 due to the pressure inside the grouting pipe 3. In the sealed state, the first water-stop tape 41 is tightly attached to the grouting pipe 3 under the tightening action of the first rubber sleeve 42. In the open state, a gap is formed between the first water-stop tape 41 and the grouting pipe 3, and the slurry inside the grouting pipe 3 can be discharged through the gap.

[0080] The first hard sheet 43 is sandwiched between the first water-stop tape 41 and the first rubber sleeve 42 and is arranged corresponding to the first slurry outlet 311; the first hard sheet 43 is made of metal sheet or hard plastic or other hard materials.

[0081] It has the following effects: the first water-stopping tape 41 has a better water-stopping effect and can improve the sealing performance of the one-way valve; the first rubber sleeve 42 has good elasticity, which can ensure the reset of the first water-stopping tape 41 on the one hand, and on the other hand, it can also provide sufficient tightening force to ensure that the first water-stopping tape 41 is tightly attached to the wall of the grouting pipe 3 in a sealed state; the first hard sheet 43 has a higher hardness and can resist negative pressure, avoiding the flexible first rubber sleeve 42 and the first water-stopping tape 41 from being partially sucked into the pipe through the first slurry outlet hole 311, causing structural damage and damage to the sealing performance.

[0082] As an improved structure of the above technical solution, a rubber sleeve can be added between the first waterstop tape 41 and the first hard plate 43, that is, the first rubber sleeve 42 is indirectly put on the first waterstop tape 41 through the added rubber sleeve. In this way, compared with the aforementioned structure, the first waterstop tape 41 is in complete contact with the added rubber sleeve, and the rubber sleeve has a better locking effect on the first waterstop tape 41.

[0083] Preferably, refer to Figure 1-Figure 3 , the grouting pipe 3 includes:

[0084] The first slurry outlet 31 is located in the inner cavity of the slurry storage bag 2. The shape of the first slurry outlet 31 can be determined according to the shape of the slurry storage bag 2. For example, if the slurry storage bag 2 is annular, the first slurry outlet 31 is configured to be an annular tubular shape that matches the slurry storage bag 2. This allows the first slurry outlet 31 to extend to different positions of the slurry storage bag 2, making grouting more uniform.

[0085] The interface 32 passes through the fixed plate 1 and communicates with the first pulp outlet 31;

[0086] The slurry inlet pipe 33 is sealed and communicated with the interface 32 .

[0087] The connection between the interface 32 and the slurry inlet pipe 33 can be a threaded connection, a flange connection, a welding connection, a socket connection or a pipe bonding connection.

[0088] The invention has the following effects: during grouting, the slurry enters from the slurry inlet pipe 33, reaches the first slurry outlet 31 through the interface 32, and then enters the slurry storage bag 2, making grouting more convenient.

[0089] Preferably, refer to Figure 3The fixing plate 1 is an annular plate, and the slurry storage bag 2 is an annular structure that matches the annular plate. The "annular" here is preferably a circular ring, but is not limited to a circular ring. The specific shape of the ring is determined by the shape of the pile hole. For example, if the pile hole is square, a square ring structure is used. The inner hole of the "annular" is preferably located at the center of the annular outer edge, but is not limited to this position and can also be arranged eccentrically.

[0090] The invention has the following effects: the annular fixed plate 1 and the slurry storage bag 2 structure ensures that, during the process of the pile end bottom grouting device sinking toward the bottom of the pile hole, the mud water and air in the pile hole will pass through the annular inner hole and enter the top of the pile end bottom grouting device, and no vortex that damages the hole wall will be formed between the pile end bottom grouting device and the pile hole, thereby effectively avoiding the problem of vortex that damages the hole wall in the pile hole due to the inability to discharge mud water and the like during the descending process of the pile end bottom grouting device, avoiding the mud water flow swirling between the edge of the fixed plate 1 and the pile hole from scouring and disturbing the hole wall, effectively preventing the hole wall collapse, excessive sediment at the bottom of the hole and broken piles, and effectively improving the construction quality and progress of the cast-in-place piles.

[0091] As a further improvement plan, refer to Figure 1 and Figure 2 , the inner ring edge of the fixed plate 1 is provided with an annular baffle 5 extending to the inner ring of the pulp bag 2. It can be made of metal or high-strength plastic plate or hard silicone or other commonly used materials with a hardness that can meet the use requirements. The annular baffle 5 can be fixed to the inner ring edge of the fixed plate 1; it can also be integrally formed with the fixed plate 1. When the pulp bag 2 is an open structure, the pulp bag 2 can be sealed and connected to the fixed plate 1 and the annular baffle 5 at the same time to form a accommodating cavity. The connection between the pulp bag 2 and the annular baffle 5 can be achieved as follows: a groove is provided on the edge of the annular baffle 5, and a pinhole is provided in the groove. The edge of the pulp bag 2 is placed in the groove, and the pulp bag 2 is bound to the annular baffle 5 by sewing technology using the groove and the pinhole; of course, the pulp bag 2 and the annular baffle 5 can also be connected by rivets or chemical adhesives or other common connection methods.

[0092] The invention has the following effects: during the construction of bored piles, it is necessary to pour concrete into the steel cage 8 equipped with a grouting device at the bottom of the pile end to form a bored pile. The annular baffle 5 can effectively form a baffle at the edge of the through hole to separate the concrete and the slurry bag 2, so as to prevent the problem that the concrete wraps around the slurry bag 2 through the inner hole of the fixed plate 1 when pouring concrete into the steel cage 8, and avoid the problem that the slurry bag 2 is wrapped by concrete and affects the grouting effect after the bored pile.

[0093] As a further improvement, refer to Figure 1 and Figure 2 The pile end bottom grouting device also includes:

[0094] a grouting pipe 6, which is in communication with the inner area of the annular baffle 5 and is suitable for injecting grout into the pile hole;

[0095] The second one-way valve 7 is provided at the communication position between the grouting pipe 6 and the inner area of the annular baffle 5 , and is suitable for preventing obstructions in the pile hole from entering the grouting pipe 6 .

[0096] The following effects are achieved: grouting pipe 6 allows for simple and convenient grouting of the interior of annular baffle 5, eliminating the virtual tip and dry ballast caused by concrete segregation at the pile bottom due to a large drop, effectively filling the interior of annular baffle 5 and thus enhancing the pile bottom strength. The provision of second one-way valve 7 ensures the normal output of slurry while also preventing external blockages such as mud, sand, and sediment from entering the grouting pipe 3.

[0097] Preferably, refer to Figure 4 A second slurry outlet hole 611 is provided on the wall of the slurry supply pipe 6, and the second one-way valve 7 includes:

[0098] The second water-stop tape 71 is wrapped around the portion of the grouting pipe 6 where the second grouting hole 611 is opened;

[0099] The second rubber sleeve 72 is directly put on the outside of the second water-stop tape 71. The second rubber sleeve 72 can be made of elastic materials such as rubber or soft silicone;

[0100] The second water-stop tape 71 and the second rubber sleeve 72 both have a sealed state in which they are tightened toward the grouting pipe 6, and an open state in which a gap is formed between the second water-stop tape 71 and the grouting pipe 6 due to the pressure inside the grouting pipe 6. In the sealed state, the second water-stop tape 71 is tightly attached to the grouting pipe 6 under the tightening action of the second rubber sleeve 72, and in the open state, a gap is formed between the second water-stop tape 71 and the grouting pipe 6, and the slurry inside the grouting pipe 6 can be discharged through the gap.

[0101] The second hard sheet 73 is sandwiched between the second water-stop tape 71 and the second rubber sleeve 72 and is arranged corresponding to the second slurry outlet 611; the first hard sheet 43 is made of metal sheet or hard plastic or other hard materials.

[0102] It has the following effects: the second water-stopping tape 71 has a better water-stopping effect and can improve the sealing performance of the one-way valve; the second rubber sleeve 72 has good elasticity, which can ensure the resetting of the second water-stopping tape 71 on the one hand, and on the other hand, it can also provide sufficient tightening force to ensure that the second water-stopping tape 71 is tightly attached to the wall of the grouting pipe 6 in a sealed state; the second hard sheet 73 has a higher hardness and can resist negative pressure, avoiding the flexible second rubber sleeve 72 and the second water-stopping tape 71 from being partially sucked into the pipe through the second slurry outlet hole 611, causing structural damage and damage to the sealing performance.

[0103] As an improved structure of the above technical solution, a layer of rubber sleeve can be added between the second waterstop tape 71 and the second hard plate 73, that is, the second rubber sleeve 72 is indirectly put on the second waterstop tape 71 through the added rubber sleeve. In this way, compared with the aforementioned structure, the second waterstop tape 71 is in complete contact with the added rubber sleeve, and the rubber sleeve has a better locking effect on the second waterstop tape 71.

[0104] Preferably, refer to Figure 1 and Figure 2 The grouting pipe 6 has a second slurry outlet 61 extending to the inner area of the annular baffle 5, and the second slurry outlet 61 is an annular pipe extending along the inner wall of the annular baffle 5. Of course, in other embodiments, the grouting pipe 6 can also be a single pipe structure, such as Figure 6 As shown; or other easily conceivable replacement structures such as two tubes.

[0105] The following effects are achieved: the second slurry outlet 61 is configured as an annular pipeline, which can better adapt to the internal area of the annular baffle 5 and transport the slurry to different positions in the area, making the slurry replenishment more uniform.

[0106] As a further improvement of the above technical solution, refer to Figure 1 and Figure 2 A detection port 21 is provided on the fixing plate 1, and the detection port 21 is suitable for filling the medium into the slurry storage bag 2 to verify whether the slurry storage bag 2 is leaking and / or the pressure it can withstand.

[0107] The following effects are achieved: the setting of the detection port 21 can determine the ultimate volume and ultimate pressure strength of the slurry bag 2 through testing, thereby facilitating the determination of more accurate preset values, thereby facilitating accurate control of the rupture timing and conditions of the slurry bag 2 during subsequent construction.

[0108] As a further improvement of the above technical solution, the pile end bottom grouting device further includes:

[0109] The protective cover is detachably connected to the fixing plate 1 and is suitable for covering the outside of the slurry storage bag 2 before construction. The protective cover can be made of aluminum foil, hard plastic, or hard silicone, etc., and is mainly used to protect the slurry storage bag 2 before construction to prevent damage to the slurry storage bag 2 from bumps; during construction, the protective cover needs to be removed from the fixing plate 1.

[0110] The present invention also provides a cast-in-place pile, referring to Figure 5 , including the aforementioned pile end bottom grouting device and a steel cage 8, the steel cage 8 is connected to the fixing plate 1 of the pile end bottom grouting device.

[0111] During specific implementation, the slurry inlet pipe 33 and the slurry supply pipe 6 can be fixedly connected to the steel cage 8 to achieve fixation.

[0112] In detail, the fixing plate 1, the grouting pipe 3, the annular baffle 5 and the grouting pipe 6 in the present invention can all be made of high-strength plastic. Specifically, they can be formed by injection molding or 3D printing.

[0113] The cast-in-place pile of the present invention has the effect of any of the aforementioned pile end bottom grouting devices because it has the effect of any of the aforementioned pile end bottom grouting devices.

[0114] The present invention also provides a construction method for the above-mentioned cast-in-place pile, which comprises the following steps in sequence:

[0115] S1. Form a pile hole and clean the sediment in the pile hole;

[0116] S2. The lower end of the pile end bottom grouting device is installed and the steel cage 8 is sunk to the bottom of the pile hole;

[0117] S3. Pour concrete into the pile hole to form a cast-in-place pile;

[0118] S4. Grouting is injected into the grout storage bag 2 to form an enlarged head at the bottom of the pile.

[0119] In step S4, the soil properties of the pile hole are controlled. If the soil is sandy, the actual grouting volume and grouting pressure are controlled to be greater than the preset values of the grout bag 2 (the preset values include two: one is the volume value of the grout bag 2 in a filled state designed when the grout bag 2 is manufactured, and the other is the preset fixed compressive strength value). This causes the grout bag 2 to rupture, allowing the cement slurry in the grout bag 2 to overflow, penetrate and consolidate the sandy soil around the pile bottom, and tightly bond the pile end enlarged head to the surrounding strata to form a whole. If the soil is clayey, the actual grouting volume and grouting pressure are controlled to be less than the preset value of the grouting bag 2 to prevent the grouting bag 2 from rupturing. During use, the grouting pressure and grouting volume should be adjusted to make the enlarged head formed at the bottom of the pile end as large as possible, thereby significantly improving the ultimate bearing capacity of the bored pile and reducing settlement. Subsequently, the grouting pipe 6 in the grouting device can directly grout the stratum at the bottom of the pile. At this time, the enlarged head formed can prevent the slurry from returning, promoting the grouting to develop deeper into the stratum, and expanding the scope of the pile bottom foundation reinforcement. Of course, in other embodiments, if the soil is sandy, the grouting bag 2 can also be controlled not to rupture; if the soil is clayey, the grouting bag 2 can also be controlled to rupture.

[0120] The following effects are achieved: This construction method utilizes the aforementioned unique pile end bottom grouting device, which can accurately select whether to rupture, as well as the timing and conditions of rupture according to different soil properties and the preset value of the slurry storage bag 2, thereby adaptively improving the bearing capacity of the bored pile.

[0121] Obviously, the above embodiments are merely examples for clarity of explanation and are not intended to limit the implementation methods. Those skilled in the art will readily appreciate that other variations or modifications based on the above descriptions are possible. It is not necessary and impossible to enumerate all implementation methods here. Obvious variations or modifications arising therefrom remain within the scope of protection of the present invention.

Claims

1. A pile end bottom grouting device, comprising: Fixed plate (1); It is characterized by further comprising: A slurry storage bag (2) is fixed on the fixed plate (1), the slurry storage bag (2) forms a receiving cavity suitable for receiving slurry or the slurry storage bag (2) and the fixed plate (1) enclose a receiving cavity suitable for receiving slurry, the slurry storage bag (2) has a filled state in which the interior is filled with slurry to support the pile body and a collapsed state in which the interior is hollow, the slurry storage bag (2) is preset with a fixed ultimate bearing strength value and has a fixed volume in the filled state; the filled state is a state in which the interior of the slurry storage bag (2) is filled with slurry and the surface is stretched tight; the collapsed state is a state in which the interior of the slurry storage bag (2) is not filled with slurry or is not fully filled with slurry and the surface is not completely stretched tight; the fixed volume in the filled state is that the slurry storage bag (2) has no elastic expansion and contraction, and the volume is fixed after the internal slurry is filled; the actual grouting pressure and grouting amount are determined according to the volume and ultimate bearing strength value of the slurry storage bag (2) in the filled state; The pulp storage bag (2) is made of chemical synthetic fiber cloth or plastic film, the chemical synthetic fiber cloth includes one of polyester, nylon, and acrylic fiber, and the plastic film includes one of polyvinyl chloride, polyethylene, and polypropylene; The pulp storage bag (2) is provided with a weak area, and the pressure-bearing strength of the weak area is lower than the pressure-bearing strength of other parts of the pulp storage bag (2) so as to form a pulp discharge area when under pressure; Also includes: A grouting pipe (3) is communicated with the inner cavity of the grout storage bag (2) and is suitable for injecting grout into the grout storage bag (2); A first one-way valve (4) is provided at a communication position between the grouting pipe (3) and the grout storage bag (2), and is suitable for preventing obstructions in the grout storage bag (2) from entering the grouting pipe (3); A first slurry outlet hole (311) is provided on the wall of the grouting pipe (3), and the first one-way valve (4) comprises: A first water-stop tape (41) is wound around the portion of the grouting pipe (3) where the first grouting hole (311) is opened; A first rubber sleeve (42) is directly or indirectly sleeved on the outside of the first water-stopping tape (41); The first water-stop tape (41) and the first rubber sleeve (42) have a sealed state in which they are tightened toward the grouting pipe (3), and an open state in which a gap is formed between them and the grouting pipe (3) under the action of the pressure in the grouting pipe (3); A first hard sheet (43) is sandwiched between the first water-stop tape (41) and the first rubber sleeve (42), and is provided corresponding to the first slurry outlet hole (311); Control is performed according to the properties of the soil forming the pile hole: if it is sandy soil, the actual grouting volume and grouting pressure are controlled to be greater than the preset value of the grouting bag (2) to cause the grouting bag (2) to rupture; if it is clay soil, the actual grouting volume and grouting pressure are controlled to be less than the preset value of the grouting bag (2) to avoid rupture of the grouting bag (2).

2. The pile end bottom grouting device according to claim 1, characterized in that: The grouting pipe (3) comprises: A first pulp outlet portion (31) is located in the inner cavity of the pulp storage bag (2); An interface (32) passes through the fixing plate (1) and is in communication with the first pulp outlet (31); The pulp inlet pipe (33) is in sealed communication with the interface (32).

3. The pile end bottom grouting device according to claim 1, characterized in that: The fixing plate (1) is an annular plate, and the pulp storage bag (2) is an annular structure adapted to the annular plate.

4. The pile end bottom grouting device according to claim 3, characterized in that: The inner ring edge of the fixed plate (1) is provided with an annular stopper (5) extending to the inner ring of the pulp storage bag (2).

5. The pile end bottom grouting device according to claim 4, characterized in that: Also includes: A grouting pipe (6) is connected to the inner area of the annular baffle (5) and is suitable for grouting into the pile hole; A second one-way valve (7) is provided at a communication position between the grouting pipe (6) and the inner area of the annular baffle (5), and is suitable for preventing obstructions in the pile hole from entering the grouting pipe (6).

6. The pile end bottom grouting device according to claim 5, characterized in that: A second slurry outlet hole (611) is provided on the wall of the slurry supply pipe (6), and the second one-way valve (7) comprises: A second water-stop tape (71) is wound around the portion of the grouting pipe (6) where the second grouting hole (611) is provided; A second rubber sleeve (72) is directly or indirectly sleeved on the outside of the second water-stopping tape (71); The second water-stop tape (71) and the second rubber sleeve (72) both have a sealed state in which they are tightened toward the grouting pipe (6), and an open state in which a gap is formed with the grouting pipe (6) under the action of the pressure in the grouting pipe (6); The second hard sheet (73) is sandwiched between the second water-stop tape (71) and the second rubber sleeve (72), and is arranged corresponding to the second slurry outlet hole (611).

7. The pile end bottom grouting device according to claim 5 or 6, characterized in that: The slurry supply pipe (6) has a second slurry outlet (61) extending to the inner area of the annular baffle (5), and the second slurry outlet (61) is an annular pipeline extending along the inner wall of the annular baffle (5).

8. The pile end bottom grouting device according to claim 1, characterized in that: The fixed plate (1) is provided with a detection port (21), and the detection port (21) is suitable for filling the medium into the pulp storage bag (2).

9. The pile end bottom grouting device according to claim 1, characterized in that: Also includes: A protective cover is detachably connected to the fixing plate (1) and is suitable for being arranged on the outside of the slurry storage bag (2) before construction.

10. A cast-in-place pile, characterized in that: include: The pile end bottom grouting device according to any one of claims 1 to 9; A steel cage (8) is connected to the fixing plate (1) of the grouting device at the bottom of the pile end.

11. A method for constructing a bored pile according to claim 10, characterized in that: The following steps are included in sequence: S1. Forming a pile hole, cleaning the sediment in the pile hole; S2. The steel cage (8) having the pile end grouting device installed at the bottom is sunk to the bottom of the pile hole; S3 pouring concrete into the pile hole to form a cast-in-place pile; S4. Grouting is injected into the grout storage bag (2) to form an enlarged head at the bottom of the pile.

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