Construction method of outer pouring concrete prefabricated composite pile

Abstract

The construction method comprises the following steps that S1, a guide hole is drilled in a to-be-reinforced area to the set depth, the depth of the guide hole is larger than the length of a prefabricated pipe pile, and the diameter of the guide hole is larger than the depth of the prefabricated pipe pile; s2, concrete is poured into the guide holes; s3, the prefabricated pipe pile is hoisted into the guide hole, and pile pressing is carried out till grout emerges; s4, the concrete is vibrated; and S5, the concrete is solidified to form a concrete outer pile layer, and the concrete outer pile layer and the prefabricated pipe pile are combined to form the composite pile. The guide hole is drilled firstly, then pile pressing is conducted in the guide hole, the prefabricated pipe pile is pressed to a larger depth conveniently, meanwhile, concrete injected in advance and sand in the guide hole are mixed and finally solidified to form the concrete outer pile layer, the concrete outer pile layer and the prefabricated pipe pile form the composite pile, and the overall length of the composite pile can reach the designed length; the problem that the sinking depth of a traditional pile is not enough is solved, and meanwhile the overall strength and the bearing capacity of the composite pile are better.

Description

Technical Field

[0001] The present application relates to the technical field of pile foundation construction, and in particular to a construction method for cast-in-place concrete prefabricated composite piles. Background Art

[0002] Pile foundations have been used in construction projects since ancient times and the materials used are varied, such as wood piles, stone piles, lime piles, cement piles, composite piles, etc. At present, reinforced concrete piles are widely used. The pile foundation can be used to reinforce the ground to meet the construction requirements.

[0003] At the current stage of pile foundation construction, it is generally necessary to drill holes in the ground first. If the sand layer is thick and the hole is deep, serious hole collapse will occur.

[0004] After the hole collapses, the length of the pile that can be driven into the ground is limited, and the effective pile length cannot be achieved. Summary of the invention

[0005] The purpose of this application is to provide a method for constructing precast composite piles of cast-in-place concrete, so as to improve the problem that the conventional jacking method cannot be applied due to the interference between the steel frame under the bridge deck and the cable tower cross brace.

[0006] The present application provides a method for constructing a cast-in-place concrete prefabricated composite pile, which adopts the following technical solution: A method for constructing a cast-in-place concrete prefabricated composite pile comprises the following steps: S1. Drilling a guide hole to a set depth in the area to be reinforced, wherein the depth of the guide hole is greater than the length of the prefabricated pipe pile, and the diameter of the guide hole is greater than the depth of the prefabricated pipe pile; S2, pouring concrete into the guide hole; S3, hoist the prefabricated pipe pile into the lead hole and press the pile until slurry emerges; S4. Vibrate the concrete; S5. The concrete solidifies to form a concrete outer pile layer, which is combined with the prefabricated pipe pile to form a composite pile.

[0007] By adopting the above technical solution, a guide hole is first drilled, and then piles are driven in the guide hole, so that the prefabricated pipe piles can be driven to a greater depth. However, the depth to which the prefabricated pipe piles can be driven is still limited. The concrete injected in advance is mixed with the sand in the guide hole and finally solidifies to form a concrete outer pile layer. The concrete outer pile layer and the prefabricated pipe piles form a composite pile, so that the overall length of the composite pile can reach the designed length, overcoming the problem of insufficient sinking depth of traditional piles. At the same time, the overall strength and bearing capacity of the composite pile are also better.

[0008] Optionally, the diameter of the guide hole is larger than the diameter of the prefabricated pipe pile and is smaller than one fifth of the diameter of the prefabricated pipe pile.

[0009] By adopting the above technical solution, space is reserved for the concrete outer pile layer so that the concrete outer pile layer can be formed.

[0010] Optionally, the concrete outer pile layer includes an overlapping portion and an extension portion, the overlapping portion is coaxially arranged outside the prefabricated pipe pile, the extension portion is connected to the overlapping portion and is located at the bottom of the prefabricated pipe pile, the circumferential dimension of the extension portion is larger than the circumferential dimension of the overlapping portion, the top surface of the overlapping portion is flush with the ground, and the top of the prefabricated pipe pile is protruding from the overlapping portion.

[0011] By adopting the above technical scheme, the composite pile formed by the combination of the concrete outer pile layer and the prefabricated pipe pile makes the reinforced area non-homogeneous and anisotropic. At the same time, under the action of load, the prefabricated pipe pile and the concrete outer pile layer can jointly bear the load and improve the overall strength. At the same time, the concrete outer pile layer expands the contact surface area of ​​the pipe pile and the contact surface between the pile and the soil, thereby increasing its friction resistance. Since the concrete outer pile layer is formed by directly pouring concrete in the hole, the sinking of the concrete outer pile layer does not need to overcome additional resistance, and then the designed length is reached through the cooperation of the extension part and the prefabricated pipe pile; the circumferential size of the extension part is larger, which can increase the ability to resist settlement and pull-out; the top of the prefabricated pipe pile is arranged to extend out of the ground, which is convenient for installing tools such as hangers on the prefabricated pipe pile.

[0012] Optionally, a steel cage is hinged at the bottom of the prefabricated pipe pile, and multiple steel cages are provided along the circumference of the prefabricated pipe pile; the steel cage has a retracted state and an expanded state, and when the steel cage is in the retracted state, the steel cage abuts against the side wall of the prefabricated pipe pile; when the steel cage is in the expanded state, the steel cage abuts against the bottom of the prefabricated pipe pile; when the steel cage abuts against the bottom of the prefabricated pipe pile, the steel cage is parallel to the axis of the prefabricated pipe pile.

[0013] By adopting the above technical solution, the bonding strength between the prefabricated pipe pile and the concrete outer pile layer is increased by the steel cage; when the prefabricated pipe pile is sunk into the hole, the pressure on the bottom of the prefabricated pipe pile is relatively large, so at this time the steel cage is switched to the retracted state to avoid damage to the steel cage; when the prefabricated pipe pile is completed, the steel cage is switched to the unfolded state to facilitate bonding with the concrete outer pile layer.

[0014] Optionally, the prefabricated pipe pile is provided with a through hole along its axial direction, and the steel cage is connected with an adjustment rope, and the end of the adjustment rope away from the steel cage passes through the top of the prefabricated pipe pile, and the adjustment rope moves to switch the steel cage between a retracted state and an expanded state.

[0015] By adopting the above technical solution, the steel cage piece can be easily adjusted by adjusting the rope to switch the angle and state of the steel cage piece.

[0016] Optionally, in step S2, the prefabricated pipe pile is lifted by a crane, and a limiting device is installed on the top of the prefabricated pipe pile, wherein the limiting device is used to be connected to the hook and to limit the prefabricated pipe pile when the pile is driven.

[0017] By adopting the above technical solution, the prefabricated pipe piles can be easily hoisted through the limiting device, and the prefabricated pipe piles can be limited during pile driving, thereby improving the accuracy of pile driving of the prefabricated pipe piles.

[0018] Optionally, the limiting device includes a limiting plate, a lifting ring for connecting to a lifting hook is provided on the limiting plate, a clamping assembly for clamping a prefabricated pipe pile is provided below the limiting plate, the top surface of the prefabricated pipe pile abuts against the bottom surface of the limiting plate, and a limiting assembly for limiting the horizontality of the limiting plate is provided on the limiting plate.

[0019] By adopting the above technical solution, the prefabricated pipe piles are clamped by the clamping assembly, thereby further improving the stability of the prefabricated pipe piles during pile pressing.

[0020] Optionally, the limit assembly includes a limit guide rail, a slider and a limit rod, the limit guide rail is installed on the ground, the slider slides on the limit guide rail, one end of the limit rod is hinged to the side wall of the limit plate, and the other end is hinged to the slider, the slider is provided with a fixing part for fixing the slider and the limit guide rail relative to each other, and multiple groups of the limit guide rail, slider and limit rod are provided along the circumference of the prefabricated pipe pile.

[0021] By adopting the above technical solution, the stability of the prefabricated pipe pile is improved during pile pressing through the cooperation of the limit guide rail, the slider and the limit rod. At the same time, when the prefabricated pipe pile is in place, the slider and the limit guide rail can be relatively fixed by the fixing parts, thereby preventing the prefabricated pipe pile from deflecting.

[0022] Optionally, a first jack is provided on the limit plate, the first jack is arranged in a vertical direction, there are multiple first jacks along the circumferential array of the prefabricated pipe piles, the number of the first jacks is the same as the number of adjustment ropes, and the movable end of each of the first jacks is connected to an adjustment rope.

[0023] By adopting the above technical solution, the adjustment rope is lifted by the first jack, and the prefabricated pipe pile is fixed in cooperation with the clamping assembly. At the same time, each first jack works independently to adjust the overall verticality of the prefabricated pipe pile.

[0024] Optionally, pressure sensors are provided on the bottom surface of the limit plate, the number of the pressure sensors is equal to the number of the first jacks, and the multiple pressure sensors correspond one-to-one to the multiple first jacks along the vertical direction.

[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. Drilling a guide hole first, and then pressing the pile in the guide hole, so as to press the prefabricated pipe pile to a greater depth, but the depth to which the prefabricated pipe pile can be pressed is still limited, and the concrete injected in advance is mixed with the sand in the guide hole, and finally solidified to form a concrete outer pile layer, and the concrete outer pile layer and the prefabricated pipe pile form a composite pile, so that the overall length of the composite pile can reach the designed length, overcoming the problem of insufficient sinking depth of traditional piles, and at the same time the overall strength and bearing capacity of the composite pile are also better; 2. The concrete outer pile layer and the prefabricated pipe pile form a composite pile, making the reinforcement area non-homogeneous and anisotropic. At the same time, under the action of load, the prefabricated pipe pile and the concrete outer pile layer can jointly bear the load and improve the overall strength. At the same time, the concrete outer pile layer expands the contact surface area of ​​the pipe pile and the contact surface between the pile and the soil, thereby increasing its friction resistance. Since the concrete outer pile layer is formed by directly pouring concrete in the hole, the sinking of the concrete outer pile layer does not need to overcome additional resistance, and then the design length is reached through the cooperation of the extension part and the prefabricated pipe pile; 3. When the prefabricated pipe pile is sunk into the hole, the bottom of the prefabricated pipe pile is under great pressure, so the steel cage is switched to the retracted state at this time to avoid damage to the steel cage; when the prefabricated pipe pile is sunk, the steel cage is switched to the unfolded state to facilitate combination with the concrete outer pile layer. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a structural schematic diagram of a cast-in-place concrete prefabricated composite pile in the first embodiment of the present invention.

[0027] Figure 2 It is a schematic diagram of a cast-in-place concrete prefabricated composite pile in the second embodiment of the present invention.

[0028] Figure 3 It is a schematic diagram of a process of constructing a cast-in-place concrete prefabricated composite pile in the second embodiment of the present invention.

[0029] Figure 4 It is a three-dimensional schematic diagram of the limiting device in the present invention.

[0030] Figure 5 It is a schematic cross-sectional view of a splint embodying the present invention.

[0031] Figure 6 It is a schematic diagram of the composite pile forming state in the present invention.

[0032] In the figure, 1. prefabricated pipe pile; 11. steel cage; 111. hinged plate; 12. adjustment rope; 13. connecting hole; 14. hinged support; 2. concrete outer pile layer; 21. overlapping part; 22. extension part; 3. limit device; 31. limit plate; 32. lifting ring; 33. limit guide rail; 34. slider; 35. limit rod; 36. fixing piece; 37. first jack; 38. clamping assembly; 381. clamping block; 382. protrusion; 283. groove; 39. pressure sensor; 4. guide hole. DETAILED DESCRIPTION

[0033] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, which only illustrate the basic structure of the present invention in a schematic manner, and therefore only show the components related to the present invention.

[0034] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present invention, unless otherwise specified, "multiple" means two or more. In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be a connection between the two elements. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0035] Embodiment 1 A precast composite pile of cast-in-place concrete, referring to Figure 1 and Figure 2, including a prefabricated pipe pile 1 and a concrete outer pile layer 2, wherein the prefabricated pipe pile 1 is provided with a through hole along its own axial direction. The concrete outer pile layer 2 includes an overlapping portion 21 and an extending portion 22 formed in one piece, wherein the overlapping portion 21 is coaxially arranged outside the prefabricated pipe pile 1, and the extending portion 22 is located at the bottom of the prefabricated pipe pile 1. The circumferential dimension of the extending portion 22 is greater than the circumferential dimension of the overlapping portion 21, and the circumferential dimension of the extending portion 22 is larger, which can increase the ability to resist settlement and pull-out. The top surface of the overlapping portion is arranged flush with the ground, and the top of the prefabricated pipe pile 1 protrudes from the overlapping portion 21. The top of the prefabricated pipe pile 1 is arranged to extend out of the ground, which is convenient for installing tools such as hangers on the prefabricated pipe pile 1.

[0036] A concrete outer pile layer 2 is poured at the bottom of the prefabricated pipe pile 1 to form a composite pile, so that the reinforced area is non-homogeneous and anisotropic. At the same time, under the action of load, the prefabricated pipe pile 1 and the concrete outer pile layer 2 can jointly bear the load and improve the overall strength. At the same time, the concrete outer pile layer 2 expands the contact surface area of ​​the pipe pile and the contact surface between the pile and the soil, thereby increasing its frictional resistance. Since the concrete outer pile layer 2 is formed by directly pouring concrete in the hole, the sinking of the concrete outer pile layer 2 does not need to overcome additional resistance, and the designed length is achieved through the cooperation of the extension part 22 and the prefabricated pipe pile 1.

[0037] Embodiment 2 The difference from the first embodiment is that a steel cage 11 is hinged at the bottom of the prefabricated pipe pile 1, and a plurality of steel cages 11 are provided along the circumference of the prefabricated pipe pile 1, so as to increase the bonding strength between the prefabricated pipe pile 1 and the concrete outer pile layer 2.

[0038] Specifically, the steel cage 11 has a stowed state and an unfolded state. When the steel cage 11 is in the stowed state, the steel cage 11 abuts against the side wall of the prefabricated pipe pile 1; when the steel cage 11 is in the unfolded state, the steel cage 11 abuts against the bottom of the prefabricated pipe pile 1. A hinge plate 111 is fixedly connected to the steel cage 11, and a hinge support 14 is fixedly connected to the side wall of the prefabricated pipe pile 1. The hinge support 14 is hinged to the hinge plate 111 so that the steel cage 11 can switch between the stowed state and the unfolded state. The hinge support 14 is interference fit with the hinge plate 111. When there is no external force, the steel cage 11 can remain relatively fixed to the prefabricated pipe pile 1.

[0039] When the prefabricated pipe pile 1 is sunk into the hole, the bottom of the prefabricated pipe pile 1 is subjected to relatively large pressure, so the steel cage 11 is switched to the retracted state at this time to prevent the steel cage 11 from being damaged; when the prefabricated pipe pile 1 is completed, the steel cage 11 is switched to the unfolded state to facilitate combination with the concrete outer pile layer 2.

[0040] In order to facilitate the adjustment of the angle of the steel cage 11, an adjustment rope 12 is fixedly connected to the steel cage 11, and one end of the adjustment rope 12 away from the steel cage 11 passes through the top of the prefabricated pipe pile 1. The steel cage 11 is switched between the retracted state and the unfolded state on the ground through the adjustment rope 12, which improves convenience.

[0041] It should be noted that when the steel cage 11 abuts against the bottom of the prefabricated pipe pile 1, the steel cage 11 is parallel to the axis of the prefabricated pipe pile 1. At this time, the abutment between the steel cage 11 and the bottom of the prefabricated pipe pile 1 prevents the steel cage 11 from continuing to rotate.

[0042] In addition, a connecting hole 13 is formed through the side wall of the prefabricated pipe pile 1 . The connecting hole 13 allows part of the concrete to enter the prefabricated pipe pile 1 when pouring concrete, so as to further increase the bonding strength between the prefabricated pipe pile 1 and the concrete outer pile layer 2 .

[0043] A construction method for cast-in-place concrete prefabricated composite piles, referring to Figures 3 to 5 , including the following steps: S1. Drill a guide hole 4 to a set depth in the area to be reinforced, the depth of the guide hole 4 is greater than the length of the prefabricated pipe pile 1, the diameter of the guide hole 4 is greater than the diameter of the prefabricated pipe pile 1, and the diameter of the guide hole 4 is greater than the depth of the prefabricated pipe pile 1. In this embodiment, the diameter of the guide hole 4 is 600 mm, and the diameter of the prefabricated pipe pile 1 is 500 mm.

[0044] S2. Pour concrete into the lead hole 4. In this embodiment, 4 m3 of concrete is poured.

[0045] S3, the prefabricated pipe pile 1 is lifted by a crane, and is placed into the lead hole 4, and the pile is pressed until slurry emerges, i.e., concrete overflows from the lead hole 4.

[0046] Specifically, a limiting device 3 is installed on the top of the prefabricated pipe pile 1, and the limiting device 3 is used to connect with the hook and limit the prefabricated pipe pile 1 when the pile is pressed. The limiting device 3 includes a limiting plate 31, and a lifting ring 32 for connecting with the hook is provided on the limiting plate 31. A clamping assembly 38 for clamping the prefabricated pipe pile 1 is provided below the limiting plate 31. The top surface of the prefabricated pipe pile 1 abuts against the bottom surface of the limiting plate 31, and a limiting assembly for limiting the horizontality of the limiting plate 31 is provided on the limiting plate 31.

[0047] More specifically, the limiting assembly includes a limiting guide rail 33, a slider 34 and a limiting rod 35. The limiting guide rail 33 is installed on the ground, the slider 34 slides on the limiting guide rail 33, one end of the limiting rod 35 is hinged to the side wall of the limiting plate 31, and the other end is hinged to the slider 34. The slider 34 is provided with a fixing member 36 for fixing the slider 34 and the limiting guide rail 33 relatively. The limiting guide rail 33, the slider 34 and the limiting rod 35 are provided in multiple groups along the circumference of the prefabricated pipe pile 1. The fixing member 36 can be a bolt.

[0048] A first jack 37 is fixedly connected to the limiting plate 31 . The first jack 37 is arranged in a vertical direction. There are multiple first jacks 37 along the circumferential array of the prefabricated pipe pile 1 . The number of the first jacks 37 is the same as the number of the adjusting ropes 12 . The movable end of each first jack 37 is connected to an adjusting rope 12 .

[0049] The clamping assembly 38 may be composed of four clamping plates, which cooperate to clamp the prefabricated pipe pile 1. Each clamping plate may be driven by a linear motor or a jack. A protrusion 382 is fixedly connected to the clamping plate, and a groove 283 matching the protrusion 382 is reserved on the side wall of the prefabricated pipe pile 1. When the clamping plate clamps the prefabricated pipe pile 1, the protrusion 382 is also inserted into the groove 283.

[0050] A receiving groove is provided on the bottom surface of the limiting plate 31 , and a pressure sensor 39 is installed in the receiving groove. The number of the pressure sensors 39 is equal to the number of the first jacks 37 , and the multiple pressure sensors 39 correspond one-to-one to the multiple first jacks 37 along the vertical direction.

[0051] Before hoisting the prefabricated pipe pile 1, first place the limit plate 31 on the top of the prefabricated pipe pile 1 so that the bottom of the prefabricated pipe pile 1 contacts the bottom surface of the limit plate 31, and at the same time use the clamping assembly 38 to clamp the prefabricated pipe pile 1, and then connect the adjustment rope 12 to the movable end of the first jack 37. Then connect the hook to the lifting ring 32, lift the prefabricated pipe pile 1 and place it in the lead hole 4, and then press the pipe pile. The area of ​​the limit plate 31 is large, so it is more convenient to press the pile. After the pile is pressed until the slurry emerges, the movable end of the first jack 37 extends, and the adjustment rope 12 moves upward, so that the steel cage 11 switches from the retracted state to the unfolded state.

[0052] S4. Vibrate the concrete so that the concrete and the sand in the introduction hole 4 are evenly mixed.

[0053] S5, concrete solidifies to form a concrete outer pile layer 2, which is combined with the prefabricated pipe pile 1 to form a composite pile. The diameter of the extension 22 of the concrete outer pile layer 2 is originally equal to the diameter of the overlapping portion 21, but during the vibration and mixing process, the concrete is mixed with the sand on the side wall of the lead hole 4, resulting in an increase in the diameter of the extension 22.

[0054] Working principle: first drill the guide hole 4, then press the pile in the guide hole 4, so as to press the prefabricated pipe pile 1 to a greater depth. However, the depth to which the prefabricated pipe pile 1 can be pressed is still limited, and the concrete injected in advance is mixed with the sand in the guide hole 4, and finally solidifies to form a concrete outer pile layer 2. The concrete outer pile layer 2 and the prefabricated pipe pile 1 form a composite pile, so that the overall length of the composite pile can reach the designed length, overcoming the problem of insufficient sinking depth of traditional piles. At the same time, the overall strength and bearing capacity of the composite pile are also better.

[0055] The pile formation properties of composite piles were analyzed, assuming that the diameter of the lead hole was 600 mm and the diameter of the prefabricated pipe pile was 500 mm.

[0056] Reference Figure 6 First, use a long spiral drill to drill a hole and pour in-situ concrete for about 4m 3 After the drill is pulled out, the concrete will fill the hole. The filling concrete in the upper soft soil layer will expand to the periphery under the action of its own weight, and the filling concrete in the underlying coarse sand layer will shrink under the pressure of the coarse sand layer. After the prefabricated pipe pile is pressed into a certain depth, it can no longer sink, and the pile end eventually stays in the coarse sand layer. After the pipe pile is pressed in, the upper lateral confinement pressure is small, the coarse sand layer has large resistance, and the concrete sinks in large quantities and accumulates in a truncated cone shape on the top surface of the coarse sand layer; this part of the accumulated concrete can provide a large amount of end resistance for the pipe pile.

[0057] Each pile is injected with 4m³ of concrete, the typical thickness of the coarse sand layer is 5.0m, and the diameter of the lead hole is 600mm. The cross-sectional area of ​​the pipe pile accounts for 1 / 2 of the cross-sectional area of ​​the pile hole. Assuming that only 1 / 3 of the concrete above the coarse sand layer is pressed to the bottom by the pipe pile to form a truncated cone, the inclination angle of the truncated cone is 45°, the upper circle diameter d is 0.1m of the pipe pile expansion, that is, 0.7m, the height of the truncated cone is H, and the lower circle diameter is D.

[0058] According to the above pile properties, the sum of the pile end concrete volume and the pile volume wrapped by concrete is: Formula 1: V1=1 / 3×(4−3.14×0.64 2 / 4×5)+0.54 2 / 4=0.862+0.196H; The volume formula of a truncated cone is Formula 2: ; Where R = D / 2, r = 0.7 / 2 = 0.35. Substituting into formula 2, we get Formula 3: ; The volume of the truncated cone is the sum of the volume of the pile end concrete and the volume of the pile wrapped by the concrete, so V1=V2, that is Formula 4: ; The inclination angle of the truncated cone is 45°. Therefore, the diameter of the lower circle of the truncated cone Formula 5: D = 2H + 0.7; Solve equation 4 and equation 5 together to get: H = 0.65m, D - 2m; The area of ​​the bottom of the truncated cone is Formula 6: A=3.14×22 / 4=3.14m2; After the pipe pile is pressed in, for the sake of simplicity of calculation, it is assumed that the diameter of the composite pile in the coarse sand layer is still 0.6m and the pile length remains unchanged. The standard value of the end resistance at the bottom of the truncated cone is selected according to the parameters of the cast-in-place pile, which is 2400kPa. Due to the high-strength squeezing effect of the pipe pile, the side resistance of the composite pile below the truncated cone can be selected according to the prefabricated pile, which is 75kPa, ignoring the bottom end resistance; the bottom resistance of the truncated cone is Formula 7: =6857KN; The side resistance of the lower pile is Formula 8: ; The ultimate bearing capacity of the composite pile is Formula 9: ; The ultimate bearing capacity of the composite pile is significantly higher than the design strength of 4800KN, exceeding it by 57.56%.

[0059] The embodiments of this specific implementation are all preferred embodiments of the present application, and are not intended to limit the protection scope of the present application. The same components are represented by the same figure marks. Therefore, any equivalent changes made based on the structure, shape, and principle of the present application should be included in the protection scope of the present application.

Claims

1. A method for constructing precast composite piles of cast-in-place concrete, characterized in that: The steps include: S1, drilling a guide hole (4) to a set depth in the area to be reinforced, the depth of the guide hole (4) being greater than the length of the prefabricated pipe pile (1), and the diameter of the guide hole (4) being greater than the depth of the prefabricated pipe pile (1); S2, pouring concrete into the lead hole (4); S3, hoisting the prefabricated pipe pile (1) into the lead hole (4), and pressing the pile until slurry emerges; S4. Vibrate the concrete; S5, the concrete solidifies to form a concrete outer pile layer (2), and the concrete outer pile layer (2) is combined with the prefabricated pipe pile (1) to form a composite pile.

2. The method for constructing a cast-in-place prefabricated composite pile according to claim 1, characterized in that: The diameter of the guide hole (4) is larger than the diameter of the prefabricated pipe pile (1) and is smaller than one fifth of the diameter of the prefabricated pipe pile (1).

3. The method for constructing a cast-in-place prefabricated composite pile according to claim 1, characterized in that: The concrete outer pile layer (2) comprises an overlapping portion (21) and an extending portion (22); the overlapping portion (21) is coaxially arranged outside the prefabricated pipe pile (1); the extending portion (22) is connected to the overlapping portion (21) and is located at the bottom of the prefabricated pipe pile (1); the circumferential dimension of the extending portion (22) is greater than the circumferential dimension of the overlapping portion (21); the top surface of the overlapping portion (21) is arranged flush with the ground; and the top of the prefabricated pipe pile (1) protrudes from the overlapping portion (21).

4. The method for constructing a cast-in-place prefabricated composite pile according to claim 2, characterized in that: A steel cage sheet (11) is hingedly connected to the bottom of the prefabricated pipe pile (1), and a plurality of the steel cage sheets (11) are arranged along the circumference of the prefabricated pipe pile (1); The steel cage sheet (11) has a retracted state and an extended state. When the steel cage sheet (11) is in the retracted state, the steel cage sheet (11) abuts against the side wall of the prefabricated pipe pile (1); when the steel cage sheet (11) is in the extended state, the steel cage sheet (11) abuts against the bottom of the prefabricated pipe pile (1); When the steel cage piece (11) abuts against the bottom of the prefabricated pipe pile (1), the steel cage piece (11) is parallel to the axis of the prefabricated pipe pile (1).

5. The method for constructing a cast-in-place prefabricated composite pile according to claim 4, characterized in that: The prefabricated pipe pile (1) is provided with a through hole along its axial direction, and the steel cage piece (11) is connected with an adjustment rope (12). One end of the adjustment rope (12) away from the steel cage piece (11) passes through the top of the prefabricated pipe pile (1), and the adjustment rope (12) moves to switch the steel cage piece (11) between a retracted state and an extended state.

6. The method for constructing a cast-in-place prefabricated composite pile according to claim 5, characterized in that: In step S3, the prefabricated pipe pile (1) is lifted by a crane, and a limiting device (3) is installed on the top of the prefabricated pipe pile (1). The limiting device (3) is used to be connected to the lifting hook and is used to limit the prefabricated pipe pile (1) when the pile is pressed.

7. The method for constructing a cast-in-place prefabricated composite pile according to claim 6, characterized in that: The limiting device (3) comprises a limiting plate (31), a lifting ring (32) for connecting to a lifting hook is provided on the limiting plate (31), a clamping assembly (38) for clamping a prefabricated pipe pile (1) is provided below the limiting plate (31), the top surface of the prefabricated pipe pile (1) is in contact with the bottom surface of the limiting plate (31), and a limiting assembly for limiting the horizontality of the limiting plate (31) is provided on the limiting plate (31).

8. The method for constructing a cast-in-place prefabricated composite pile according to claim 7, characterized in that: The limiting assembly comprises a limiting guide rail (33), a slider (34) and a limiting rod (35); the limiting guide rail (33) is installed on the ground; the slider (34) slides on the limiting guide rail (33); one end of the limiting rod (35) is hinged to the side wall of the limiting plate (31), and the other end is hinged to the slider (34); a fixing member (36) is provided on the slider (34) for fixing the slider (34) and the limiting guide rail (33) relatively; and a plurality of groups of the limiting guide rail (33), the slider (34) and the limiting rod (35) are provided along the circumference of the prefabricated pipe pile (1).

9. The method for constructing a cast-in-place prefabricated composite pile according to claim 8, characterized in that: The limiting plate (31) is provided with a first jack (37), which is arranged in a vertical direction. There are a plurality of the first jacks (37) along the circumferential array of the prefabricated pipe pile (1), and the number of the first jacks (37) is the same as the number of the adjustment ropes (12). The movable end of each of the first jacks (37) is connected to an adjustment rope (12).

10. A method for constructing precast composite piles of cast-in-place concrete according to claim 9, characterized in that: A pressure sensor (39) is provided on the bottom surface of the limit plate (31), the number of the pressure sensors (39) is equal to the number of the first jacks (37), and the plurality of pressure sensors (39) correspond one-to-one to the plurality of first jacks (37) along the vertical direction.

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