Cast-in-place pile construction method
By forming non-circular pile holes using a drilling device, and then filling the holes with grout using a combination of end plates and sleeves, the problem of insufficient bearing capacity of existing cast-in-place piles is solved, achieving the effects of simplified construction and reduced costs.
Patent Information
- Application Number
- CN202511465581.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-10-14
- Publication Date
- 2025-11-28
AI Technical Summary
In existing cast-in-place pile construction methods, the friction between the pile side surface and the borehole wall is relatively small, resulting in insufficient bearing capacity, and the construction is cumbersome and costly.
Non-circular pile holes are formed using a drilling device. By combining end plates and sleeves, grout is filled through grouting channels to increase the pile hole area, improve friction, simplify construction procedures, and avoid the use of drilling machinery.
It improves the bearing capacity of cast-in-place piles, simplifies construction procedures, reduces construction costs, enhances borehole wall stability, and increases friction and end resistance.
Smart Images
Figure CN121024055A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present application relates to a cast-in-place pile construction method, belonging to the technical field of pile foundation construction in building engineering. BACKGROUND
[0002] As shown in the prior art cast-in-place pile construction method mainly includes drilling, hole cleaning, installing reinforcement cage, pouring concrete and other steps, first using drilling machinery drilling, and then the reinforcement cage and grouting pipe are implanted into the pile hole, and then the slurry or concrete is injected into the pile hole. The drilling operation is relatively cumbersome, and a pile casing is usually required, which prolongs the construction period. Figure 1
[0003] The pile foundation provides bearing capacity mainly depending on two aspects: pile end (pile bottom) resistance and friction between pile side surface and hole wall. In the prior art, the hole formed by the mechanical drilling equipment is only a circular hole, and the cast-in-place pile is also circular. The surface area of the cast-in-place pile is limited, resulting in small friction between the cast-in-place pile side surface and the hole wall, and the bearing capacity of the cast-in-place pile cannot be fully utilized. In addition, the use of mechanical drilling equipment and the transportation of drilling waste increase the construction process and construction cost. SUMMARY
[0004] In order to overcome the problems in the prior art, the present application provides a cast-in-place pile construction method, which is beneficial to improve the bearing capacity of the cast-in-place pile and simplify the construction process. The specific technical scheme is as follows.
[0005] A cast-in-place pile construction method, characterized by using a hole forming device to form a pile hole, the hole forming device comprising an end plate and a sleeve, the lower end of the sleeve abutting against the end plate; the area of the end plate is greater than the cross-sectional area of the sleeve; the lower end of the sleeve is provided with a grouting channel, the grouting channel communicating the inner and outer spaces of the sleeve; the construction method comprising the following steps:
[0006] 1) using pile sinking machinery to press down the hole forming device to form a pile hole, the sleeve of the hole forming device being filled with slurry, as the end plate of the hole forming device continuously descends, the slurry in the sleeve is filled into the gap between the sleeve and the pile hole through the grouting channel;
[0007] 2) after the hole forming device is sunk to the specified position, the sleeve is pulled out upward from the pile hole, and the end plate is left at the bottom of the pile hole.
[0008] Further, in the step 2), during the pulling out of the sleeve, the slurry is supplemented into the pile hole.
[0009] Further, in the step 1), before pressing down the hole forming device, a reinforcement cage is placed outside the sleeve, and the bottom of the reinforcement cage is fixed with the end plate.
[0010] Further, after the sleeve is pulled out of the pile hole, the reinforcement cage is placed into the pile hole.
[0011] Further, the edges of the end plate are fixedly provided with vertical upward extending surrounding plates, and all the surrounding plates together form a cylindrical shape; when the hole-forming device is pressed down, the surrounding plates are located at the periphery of the grouting channel. During the process of pressing down the hole-forming device, the end plate is generally in a horizontal state, the surrounding plates are generally in a vertical state, and the grouting hole at the lower end of the sleeve is protected by the surrounding plates, so that even if the ground is soft, the grouting hole can be prevented from being blocked; at the same time, all the surrounding plates together form a cylindrical shape, which has a certain supporting effect on the pile hole wall formed by the end plate, and is beneficial to improve the stability of the hole wall and prevent the hole wall from collapsing or reducing in diameter.
[0012] Further, the end plate is a circular plate or a polygonal plate. Preferably, the end plate is a hexagonal star-shaped plate. Compared with the circular end plate, the polygonal plate (the hexagonal star-shaped plate is one of the polygonal plates) has a significantly increased circumference, thereby increasing the hole wall area of the pile hole and improving the friction between the cast-in-place pile and the hole wall.
[0013] Further, a rib plate is arranged below the end plate, the rib plate is perpendicular to the end plate, and the rib plate is fixedly connected with the end plate; preferably, six rib plates are radially distributed below the end plate. By arranging the rib plate, on the one hand, the rigidity of the end plate is improved, which is beneficial to prevent or reduce the bending of the end plate, and on the other hand, the rib plate in a generally vertical state is beneficial to ensure that the entire hole-forming device maintains a vertical state when being pressed into the soil, thereby preventing or reducing the inclination of the hole-forming device. Preferably, the outer lower end of the rib plate is provided with a chamfer.
[0014] Further, the grouting channel is a grouting hole arranged on the lower end side wall of the sleeve; or a plurality of spacers are arranged between the end plate and the sleeve, and the adjacent spacers form the grouting channel. The grouting channel ensures that the slurry in the sleeve can be smoothly injected into the gap between the sleeve and the pile hole.
[0015] Further, the end plate is provided with a positioning mechanism for limiting the sleeve to be located at the center of the end plate. Preferably, the positioning mechanism comprises protrusions distributed along the outer surface or the inner surface of the sleeve. Preferably, the positioning mechanism is a groove arranged on the end plate, and the groove is used to accommodate the lower end of the sleeve.
[0016] Compared with the prior art, the present application has the following beneficial effects.
[0017] 1. The area of the end plate is larger than the cross-sectional area of the sleeve, and the end plate is preferably a polygonal plate, so that the pile hole formed is non-circular, which is beneficial to increase the hole wall area of the pile hole, thereby improving the friction between the cast-in-place pile and the hole wall;
[0018] 2. Since the area of the end plate is larger than the cross-sectional area of the sleeve, the pile hole wall formed by the end plate has a certain gap from the sleeve, so that the sleeve is not in contact with the rock-soil, completely eliminating the side resistance of the rock-soil to the sleeve during the hole forming process, and the hole forming difficulty is small; at the same time, since the sleeve is not in contact with the hole wall, the difficulty of pulling out the sleeve is also reduced, and the requirement for construction equipment is reduced;
[0019] 3. Grouting is performed by filling grout into the sleeve, which is convenient and easy to perform, and has low requirements for grouting equipment.
[0020] 4. By providing a surrounding plate on the end plate, on the one hand, it is beneficial to avoid the blockage of the grouting hole, and ensure the smooth grouting of the grout from the inside of the sleeve to the pile hole; on the other hand, it is beneficial to improve the stability of the hole wall of the pile hole, prevent the collapse of the hole wall, and improve the application range of the cast-in-place pile.
[0021] 5. The construction process is simplified, and neither drilling machinery nor external transportation of waste soil is required;
[0022] 6. After the soil is squeezed to form a hole, the rock-soil on the side and bottom of the pile is squeezed and compacted, which greatly improves the side resistance and end resistance. BRIEF DESCRIPTION OF DRAWINGS
[0023] Figure 1 is a schematic diagram of the existing cast-in-place pile construction;
[0024] Figure 2 is a schematic diagram of the hole forming device;
[0025] Figure 3 is a schematic diagram of the hole forming device after the sleeve is removed;
[0026] Figure 4 is a bottom view of the hole forming device;
[0027] Figure 5 is a top view of the hole forming device;
[0028] Figure 6 is a schematic diagram of the hole forming device of the modified example;
[0029] Figure 7 is a schematic diagram of the construction of the cast-in-place pile.
[0030] Figure 8 is Figure 7 is an enlarged view of the A area in
[0031] Figure 9is another embodiment of the grouting channel.
[0032] Fig. The hole forming device 1, end plate 1.1, sleeve 1.2, grouting hole 1.3, rib plate 1.4, positioning mechanism 1.5, coaming 1.6, cushion block 1.7, pile hole 2, pile driving machinery 3, slurry 4, reinforcement cage 5. DETAILED DESCRIPTION
[0033] The application will be further described in detail below with reference to the accompanying drawings.
[0034] Referring to Figures 2-8 , a cast-in-place pile construction method, using a hole forming device 1 to form a pile hole 2, the hole forming device 1 includes an end plate 1.1 and a sleeve 1.2, the lower end of the sleeve 1.2 abuts against the end plate 1.1; the area of the end plate 1.1 is greater than the cross-sectional area of the sleeve 1.2; the side wall of the lower end of the sleeve 1.2 has a grouting hole 1.3 (the grouting hole 1.3 forms a grouting channel); the sleeve 1.2 and the end plate 1.1 are preferably made of steel to ensure their reliable structural stability, so that the sleeve 1.2 can be repeatedly used;
[0035] As Figure 4 shown, the end plate 1.1 is a polygonal plate. Preferably, the end plate 1.1 is a hexagonal star-shaped plate. The perimeter of the end plate 1.1 of the polygonal plate (the hexagonal star-shaped plate is one of the polygonal plates) is greatly increased compared to the end plate 1.1 of a circular shape, thereby increasing the hole wall area of the pile hole 2 (the cross-sectional shape of the pile hole 2 is determined by the shape of the end plate 1.1), thereby improving the friction between the cast-in-place pile and the hole wall.
[0036] Preferably, as Figure 2 , Figure 5 shown, the edges of the end plate 1.1 are fixedly provided with coamings 1.6 extending vertically upward, and all the coamings 1.6 together form a cylindrical shape; when the hole forming device 1 is pressed down, the coamings 1.6 are located at the periphery of the grouting hole 1.3 of the sleeve 1.2. During the process of pressing down the hole forming device 1, the end plate 1.1 is generally in a horizontal state, the coamings 1.6 are generally in a vertical state, and the grouting hole 1.3 at the lower end of the sleeve 1.2 is protected in the coamings 1.6, so that even if the foundation is soft, the grouting hole 1.3 can also be prevented from being blocked; at the same time, all the coamings 1.6 together form a cylindrical shape, which has a certain supporting effect on the hole wall of the pile hole 2 formed by the end plate 1.1, which is conducive to improving the stability of the hole wall and preventing the hole wall from collapsing. It should be noted that in the case of good geotechnical conditions and the grouting hole 1.3 is not blocked, the coamings 1.6 can be cancelled (as Figure 6 shown).
[0037] Preferably, the lower part of the end plate 1.1 is provided with a rib plate 1.4, which is perpendicular to the end plate 1.1 and is fixedly connected with the end plate 1.1; preferably, six rib plates 1.4 are distributed in a radial manner below the end plate 1.1. By providing the rib plate 1.4, on the one hand, the rigidity of the end plate 1.1 is improved, which is conducive to preventing or reducing the bending of the end plate 1.1, and on the other hand, the rib plate 1.4 in a generally vertical state is conducive to ensuring that the entire hole-forming device 1 remains in a vertical state when being pressed into the soil, thereby preventing or reducing the inclination of the hole-forming device 1. Preferably, the outer lower end of the rib plate 1.4 is provided with a chamfer. It should be noted that the rib plate 1.4 can be cancelled in some cases (for example, as shown in Figure 6 , as long as the structural strength of the end plate 1.1 can be ensured.
[0038] Preferably, the end plate 1.1 is provided with a positioning mechanism 1.5 for limiting the sleeve 1.2 to be located at the center of the end plate 1.1. Preferably, the positioning mechanism 1.5 includes protrusions (as shown in Figure 2 , Figure 5 distributed along the outer surface or the inner surface of the sleeve 1.2. In an alternative embodiment, the positioning mechanism 1.5 is a groove (not shown) on the end plate 1.1, which is used to accommodate the lower end of the sleeve 1.2.
[0039] As shown in Figures 7-8 , the construction method of the cast-in-place pile includes the following steps:
[0040] 1) The hole-forming device 1 is pressed into the ground by the pile sinking machinery 3 (hammering or static pressure equipment) to form the pile hole 2, the sleeve 1.2 of the hole-forming device 1 is filled with the slurry 4, and as the end plate 1.1 of the hole-forming device 1 continues to descend, the slurry 4 in the sleeve 1.2 is filled into the gap between the sleeve 1.2 and the pile hole 2 through the grouting hole 1.3; wherein the filling of the slurry 4 into the sleeve 1.2 can adopt the existing conventional method, such as filling the slurry into the top opening of the sleeve 1.2 through a grouting pipe (not shown), or filling the slurry into the grouting channel formed in the top side wall of the sleeve 1.2, etc.
[0041] 2) After the hole-forming device 1 is sunk to the designated position, the sleeve 1.2 is pulled out of the pile hole 2, the end plate 1.1 is left at the bottom of the pile hole 2, and the reinforcement cage 5 is placed into the pile hole 2. When the sleeve 1.2 moves upward, the sleeve 1.2 and the end plate 1.1 can be separated; that is, the sleeve 1.2 and the end plate 1.1 are not fixedly connected, during the hole-forming, the hole-forming force (striking force) of the pile sinking machinery 3 is transmitted downward to the end plate 1.1 through the sleeve 1.2, when the hole sinking is completed, the sleeve 1.2 is pulled upward, and the sleeve 1.2 is separated from the end plate 1.1, and the end plate 1.1 remains at the bottom of the pile hole 2 to be used as the pile end of the cast-in-place pile.
[0042] In another embodiment, as shown in Figure 9As shown, the grouting hole 1.3 on the sleeve 1.2 is removed, and several pads 1.7 are set between the end plate 1.2 and the sleeve 1.2. The gap between adjacent pads 1.7 forms a grouting channel, thereby ensuring that the grout in the sleeve 1.2 can be smoothly injected into the gap between the sleeve 1.2 and the pile hole 2.
[0043] In this construction method, grouting is performed simultaneously during the hole-forming process. The grout 4 provides reverse pressure to the soil around the hole, preventing stress relaxation and strength reduction. Pressure grouting is not required; it relies on pile driving vibration and gravity-driven grout flow (although pressure grouting can also be performed using grouting equipment). The inherent repeated vibrations during the hole-forming process allow the grout 4 to penetrate into the soil fissures surrounding the pile hole 2, thereby reinforcing the soil around the pile and further improving soil strength and the bond between the grout 4 and the soil.
[0044] In step 2), during the removal of the sleeve 1.2, grout 4 is added into the pile hole 2 to ensure that the entire pile hole 2 is filled with grout. After the grout solidifies, a complete cast-in-place pile is formed. Grout 4 can be concrete or other grouting materials, such as cement mortar, cement paste, anchor grout, etc.
[0045] In another embodiment, in step 1), before pressing down the hole-forming device 1, a reinforcing cage 5 is placed outside the sleeve 1.2. The bottom of the reinforcing cage 5 is fixed to the end plate 1.1, but the reinforcing cage 5 and the sleeve 1.2 are not fixed together, which facilitates the later removal of the sleeve 1.2 from the pile hole 2. It should be noted that in some cases, the reinforcing cage 5 can be omitted, as long as the cast-in-place pile meets the design strength requirements, such as CFG piles.
[0046] The embodiments of the present invention have been described above with reference to the accompanying drawings. Unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention is not limited to the specific embodiments described above; these embodiments are merely illustrative and not limiting. Those skilled in the art, under the guidance of the present invention, can make many modifications without departing from the spirit and scope of the claims, and all such modifications fall within the scope of protection of the present invention.
Claims
1. A method for constructing cast-in-place piles, characterized in that, A pile hole (2) is formed using a hole-forming device (1). The hole-forming device (1) includes an end plate (1.1) and a sleeve (1.2). The lower end of the sleeve (1.2) abuts against the end plate (1.1). The area of the end plate (1.1) is larger than the cross-sectional area of the sleeve (1.2). A grouting channel is provided at the lower end of the sleeve (1.2), which connects the inner and outer spaces of the sleeve (1.2). The construction method includes the following steps: 1) The pile driving machine (3) is used to press down the hole forming device (1) to form a pile hole (2). The sleeve (1.2) of the hole forming device (1) is filled with grout (4). As the end plate (1.1) of the hole forming device (1) continues to descend, the grout (4) in the sleeve (1.2) is filled into the gap between the pile hole (2) and the sleeve (1.2) through the grouting channel. 2) When the hole-forming device (1) sinks to the designated position, the sleeve (1.2) is pulled out of the pile hole (2) and the end plate (1.1) remains at the bottom of the pile hole (2).
2. The method for constructing cast-in-place piles according to claim 1, characterized in that, In step 2), during the process of pulling out the sleeve (1.2), grout (4) is added into the pile hole (2).
3. The method for constructing cast-in-place piles according to claim 1, characterized in that, In step 1), before pressing down the hole-forming device (1), a steel cage (5) is placed outside the sleeve (1.2), and the bottom of the steel cage (5) is fixed to the end plate (1.1).
4. The method for constructing cast-in-place piles according to claim 1, characterized in that, In step 2), after the sleeve (1.2) is pulled out of the pile hole (2), the steel cage (5) is placed into the pile hole (2).
5. The method for constructing cast-in-place piles according to claim 1, characterized in that, The edge of the end plate (1.1) is fixedly provided with a vertically upward extending surrounding plate (1.6), and all the surrounding plates (1.6) together form a cylindrical shape; when the hole forming device (1) is pressed down, the surrounding plate (1.6) is located on the periphery of the grouting channel.
6. The method for constructing cast-in-place piles according to claim 1, characterized in that, The end plate (1.1) is a circular plate or a polygonal plate; preferably, the end plate (1.1) is a hexagonal star-shaped plate.
7. The method for constructing cast-in-place piles according to claim 1, characterized in that, The grouting channel is a grouting hole (1.3) provided on the lower side wall of the sleeve (1.2); or a plurality of pads (1.7) are provided between the end plate (1.2) and the sleeve (1.2), and the grouting channel is formed between adjacent pads (1.7).
8. The method for constructing cast-in-place piles according to claim 1, characterized in that, A rib (1.4) is provided below the end plate (1.1), the rib (1.4) is perpendicular to the end plate (1.1), and the rib (1.4) is fixedly connected to the end plate (1.1).
9. A method for constructing cast-in-place piles according to claim 1, characterized in that, The end plate (1.1) is provided with a positioning mechanism, which is used to limit the sleeve (1.2) to be located at the center of the end plate (1.1).
10. A method for constructing cast-in-place piles according to claim 9, characterized in that, The positioning mechanism (1.5) includes protrusions distributed along the outer or inner surface of the sleeve (1.2); or the positioning mechanism (1.5) is a groove located on the end plate (1.1) for receiving the lower end of the sleeve (1.2).