Cast-in-place pile self-slag-removing and pouring coupling device and construction method

Abstract

The invention discloses a self-slag-removing and grouting coupling device for a cast-in-place pile. The self-slag-removing and grouting coupling device comprises a flow guide reinforcement cage and a grouting assembly. The grouting assembly is arranged in the flow guide reinforcement cage and is parallel to or coincides with the axis of the flow guide reinforcement cage. The flow guide reinforcement cage comprises a reinforcement cage body and spiral flow guide blades welded to the periphery of the reinforcement cage body. The spiral flow guide blades spirally extend in the height direction of the reinforcement cage. The grouting assembly comprises a grouting guide pipe, a threaded pile casing and a connecting piece. The threaded pile casing is rotationally connected to the periphery of the bottom of the grouting guide pipe through the connecting piece so as to rotate around the axis of the grouting guide pipe. And a thread formed on the outer surface of the threaded protective cylinder is matched with the spiral extension direction of the spiral flow guide blade. The invention further discloses a cast-in-place pile self-slag-removing and pouring combined construction method. The cast-in-place pile self-slag-removing and pouring combined construction device is adopted for removing sediment at the bottom of a pile while concrete is poured. According to the device and the construction method, the slag removal efficiency and the pile forming quality of the cast-in-place pile are improved.

Description

Technical Field

[0001] The invention relates to the technical field of building pile foundation engineering construction, and in particular to a self-cleaning and pouring coupling device for a cast-in-place pile and a construction method. Background Art

[0002] In the field of bored cast-in-place pile construction, the treatment of pile bottom sediment is a key technical problem that affects the bearing capacity of pile foundation. In traditional processes, physical removal methods such as high-pressure jet hole cleaning and mechanical grab bucket slag removal are usually used. Such processes require a separate slag removal process before pouring, which leads to interruption of the construction process. In addition, due to the depth and diameter of the pile hole, there are problems such as large slag removal blind area and poor equipment adaptability. There is a technology that pre-places a crushed stone cushion layer at the bottom of the pile, but this method is not only difficult to construct and increases material costs, but also easily exacerbates the risk of uneven foundation settlement due to uneven cushion density. In addition, traditional processes often use the concrete's own impact force to achieve sediment stripping and floating during the concrete pouring stage. However, especially in the construction of large-diameter piles, due to the insufficient impact force of the concrete and the turbulent flow state, it is difficult to form an effective lifting force on the sediment, resulting in the sediment and the pile bottom The bonding force cannot be completely broken, and the slag removal effect is not good. Although current technological development attempts to introduce fluid mechanics principles to optimize the catheter structure, the slag flushing capacity is still limited.

[0003] There is an urgent need for an innovative solution that combines dynamic energy conversion and process integration to simultaneously complete sediment stripping, lifting and discharge during concrete pouring, fundamentally improving the slag removal efficiency and pile quality. Summary of the invention

[0004] The main technical problem to be solved by the present invention is to provide a slag cleaning and pouring device and a construction method for a bored pile, so as to improve the efficiency of the slag cleaning operation and the pile quality of the bored pile.

[0005] In order to solve the above technical problems, the present invention provides a self-cleaning and pouring coupling device for cast-in-place piles, comprising a guide steel cage and a grouting assembly; the grouting assembly is arranged in the guide steel cage and is parallel to or coincident with the axis of the guide steel cage;

[0006] The guide steel cage includes a steel cage and spiral guide vanes welded to the outer periphery of the steel cage; the spiral guide vanes extend spirally along the height direction of the steel cage to provide lifting force to the flowing concrete slurry and guide it to form a vortex;

[0007] The grouting assembly includes a grouting conduit, a threaded sleeve and a connecting piece; the threaded sleeve is rotatably connected to the bottom periphery of the grouting conduit through the connecting piece so as to rotate around the axis of the grouting conduit driven by the vortex; the threaded sleeve has a thread structured on the outer surface that matches the spiral extension direction of the spiral guide vane.

[0008] In a preferred embodiment, the grouting conduit is constructed as a threaded structure near the grout outlet.

[0009] In a preferred embodiment, the spiral guide vanes are arranged throughout the outer circumference of the steel cage.

[0010] In a preferred embodiment, the spiral guide vane forms a spiral surface with a concave center.

[0011] In a preferred embodiment, the connecting member includes a rotating support and a plurality of connecting rods; the rotating support is axially rotatably connected to the grouting conduit; one end of the plurality of connecting rods is detachably connected to the rotating support, and the other end is connected to the top of the threaded casing.

[0012] In a preferred embodiment, the rotating support is provided with a plurality of slots at intervals along the circumference direction, and the slots include a countersunk hole provided at the top of the rotating support and a slot communicating with the countersunk hole;

[0013] The connecting rod enters or exits the clamping slot through the slot; the connecting rod is provided with a protrusion at the top end, the protrusion is placed in the countersunk hole and is limitedly matched with the slot.

[0014] In a preferred embodiment, a circular through cavity is constructed in the middle of the rotating support along the thickness direction; a group of bearings are fixed in the circular through cavity; and the inner ring of the bearing is fixed on the surface of the grouting conduit.

[0015] In a preferred embodiment, the pitch of the spiral guide vane is 0.2 to 0.3 times the diameter of the pile hole.

[0016] In a preferred embodiment, the spiral guide vanes are made of steel sheets or plates with a thickness of 5 to 15 mm.

[0017] The present invention also provides a method for the combined construction of self-cleaning and pouring of cast-in-place piles, which uses the device described above. When pouring concrete, the vortex and lifting force formed by the spiral guide blades guiding the concrete slurry are used to flush out the sediment slurry at the bottom of the pile hole, and the buoyancy of the concrete slurry on the sediment slurry is combined to lift the sediment slurry to the mouth of the pile hole; the vortex drives the threaded casing to rotate to enhance the vortex lift.

[0018] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0019] The present invention combines the basic principles of fluid mechanics, optimizes the structural structure and connection of the self-cleaning and pouring coupling device, and realizes the effective self-removal of pile bottom sediment during the pouring process of the bored pile. On the one hand, the multi-directional three-dimensional lifting force provided by the device makes the viscosity between the sediment slurry and the pile bottom more effectively broken, thereby enhancing the slag removal effect and improving the construction quality of the pile foundation. On the other hand, thanks to the device, construction personnel can organically combine the slag removal operation with the pouring process, avoiding the separation of the hole cleaning and grouting processes in the traditional process, which is of great significance for simplifying the construction process, reducing construction investment, and improving construction efficiency. In addition, the detachable threaded casing facilitates the disassembly, assembly, turnover and maintenance of the equipment. Therefore, the device and the construction method simultaneously solve the technical problems of incomplete slag removal and complicated processes in the traditional process by constructing an innovative pile bottom self-cleaning system, and have high engineering reference significance and broad engineering application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a three-dimensional schematic diagram of the self-slag cleaning and pouring coupling device in an embodiment of the present invention;

[0021] Figure 2 It is a three-dimensional schematic diagram of the flow-guiding steel cage described in an embodiment of the present invention;

[0022] Figure 3 is a three-dimensional schematic diagram of the grouting assembly described in an embodiment of the present invention;

[0023] Figure 4 It is a three-dimensional schematic diagram of the threaded sleeve and the connecting piece described in the embodiment of the present invention;

[0024] Figure 5 is a three-dimensional schematic diagram of the connecting member described in an embodiment of the present invention;

[0025] Figure 6 It is a schematic diagram of the threaded section at the grout outlet of the grouting conduit in the embodiment of the present invention;

[0026] Figure 7 It is a schematic diagram of the combined construction of self-cleaning and pouring of bored piles in an embodiment of the present invention.

[0027] Markings in the figure are: 1-rebar cage, 2-spiral guide vane, 3-grouting conduit, 31-threaded section, 4-threaded casing, 5-connector, 51-rotating support, 511-circular through cavity, 512-bearing, 513-slot, 5131-countersunk hole, 5132-slot, 52-connecting rod, 521-protrusion, 6-concrete slurry, 7-sediment slurry, 8-pile hole. DETAILED DESCRIPTION

[0028] The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention; it is obvious that the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments, and all other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "upper", "lower", "inner", "outer", "top / bottom" 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 position, be constructed and operated in a specific position, and therefore cannot be understood as limiting the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0030] In the description of the present invention, it should be noted that, unless otherwise clearly stipulated and limited, the terms "installed", "provided with", "installed / connected", "connected", etc. should be understood in a broad sense. For example, "connection" can be a wall-mounted 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 an indirect connection through an intermediate medium. It can be the internal connection of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0031] like Figure 1 to Figure 7 As shown, an embodiment of the present invention provides a self-cleaning and grouting coupling device for bored piles, including a guide steel cage and a grouting assembly. The guide steel cage includes a steel cage 1 and a spiral guide vane 2 welded to the outer periphery of the steel cage 1. The grouting assembly includes a grouting conduit 3, a threaded sleeve 4 and a connector 5, and the threaded sleeve 4 is rotatably connected to the bottom periphery of the grouting conduit 3 through the connector 5. The specific structure and connection method of the device are further described below in conjunction with the illustrations.

[0032] like Figure 2As shown, the steel cage 1 is cylindrical and is welded by a number of longitudinal force-bearing main bars, annular stirrups and spiral stirrups. The spiral guide vane 2 is made of steel sheet or thin steel plate, and extends spirally along the height direction of the steel cage 1. Preferably, the spiral guide vane 2 is arranged at the outer periphery of the steel cage 1. The spiral guide vane 2 constructs a spiral curved surface with a concave center, that is, in any diameter direction, the spiral guide vane 2 extends outward at a horizontal upward inclination. In this embodiment: the thickness of the spiral guide vane 2 is set to 5 to 15 mm, and the width is 30 cm; the pitch, that is, the spacing between two adjacent layers of spiral guide vanes 2 is set to 0.2 to 0.3 times the diameter of the pile hole; the guide angle, that is, the horizontal inclination angle of the spiral guide vane 2 is set to 30°.

[0033] like Figure 4 , Figure 5 As shown, the connecting member 5 is shaped like a flying chair facility as a whole, including a rotating support 51 and a plurality of connecting rods 52. The rotating support 51 is constructed with a circular through cavity 511 penetrating in the middle along the thickness direction. A group of bearings 512 are fixed in the circular through cavity 511, and the bearings 512 are sleeved on the outer periphery of the grouting conduit 3 and fixed by welding, so that the rotating support 51 can rotate around the grouting conduit 3. The outer periphery of the rotating support 51 is provided with a plurality of slots 513 at intervals along the circumference direction, and the slots 513 include a countersunk hole 5131 and a slot 5132 connected to the countersunk hole 5131. Specifically, the rotating support 51 is recessed from the top to form the countersunk hole 5131; at the position corresponding to the countersunk hole 5131, the rotating support 51 cuts out the vertical or oblique slot 5132 from the outer wall.

[0034] The plurality of connecting rods 52 are equivalent to the spokes of the flying chair facility. The connecting rod 52 is configured with a spherical protrusion 521 at one end. The minimum width of the connecting rod 52 is smaller than the width of the slot 5132; the minimum width of the protrusion 521 is larger than the width of the slot 5132, and the maximum width is smaller than the inner diameter of the counterbore 5131. Preferably, the depth of the counterbore 5131 is not less than the height of the protrusion 521, that is, not less than the diameter of the protrusion 521 in this embodiment. Based on this structural relationship, when installing, the connecting rod 52 is inserted into the slot 5132 laterally and then pulled down, and the protrusion 521 is inserted into the counterbore 5131. The protrusion 521 is clamped in the clamping groove 513 by limiting the slot 5132 in the vertical direction or the horizontal direction, so as to realize the detachable connection between the connecting rod 52 and the rotating support 51. The end of the connecting rod 52 away from the rotating support 51 is welded to the top of the spiral casing. In this way, the spiral casing can rotate around the grouting conduit 3 together with the rotating support 51 under the action of external force. The threads on the outer surface of the spiral casing 4 match the spiral extension direction of the spiral guide vane 2 to enhance the vortex effect of the concrete slurry 6 during rotation.

[0035] like Figure 7 As shown, during the grouting construction, the guide steel cage is centrally inserted in the pile hole 8. The grouting conduit 3 is connected to the threaded casing 4 and then inserted into the guide steel cage, parallel to or coincident with the axis of the guide steel cage. Figure 6 As shown, in this embodiment, the grouting conduit 3 is constructed as a threaded structure near the grouting outlet, hereinafter referred to as the threaded grouting section.

[0036] like Figure 7As shown, in actual slag removal construction, in order to improve the fluidity of the pile bottom sediment, mud will be injected in advance to bond and entrain the pile bottom sediment. Hereinafter, this part of the mud mixed with sediment is referred to as sediment mud 7. During the grouting construction, the grouting conduit 3 is sprayed from a height of 2 to 15 cm from the bottom of the pile hole 8. The high-pressure sprayed concrete slurry 6 accelerates the tangential flow under the constraint of the threaded grouting section, and forms an initial vortex at the slurry outlet. The initial vortex flows at high speed around under the guidance of the pile bottom and rushes to the spiral guide vane 2 on the periphery. On the one hand, the spiral guide vane 2 with a certain inclination angle decomposes the dynamic pressure and drag force from the concrete slurry 6 into an upward lifting force. At the same time, the concrete slurry 6 forms a local vortex when it spirally climbs along the surface of the spiral guide vane 2, driving the inner threaded casing 4 to rotate. The threaded sleeve 4 is constructed with a thread on the outer surface that matches the spiral extension direction of the spiral guide vane 2, so that the threaded sleeve 4 further strengthens and gathers the local vortex when rotating, so that the concrete slurry 6 generates a stable vortex lift. Under the three-dimensional action of the lifting force and the vortex lift, the sediment slurry 7 is rolled up from the pile bottom to separate from the pile bottom. As the concrete is poured, the sediment slurry 7 with a smaller overall density continues to be lifted up under the buoyancy of the concrete slurry 6. A small part of the sediment slurry 7 and the concrete slurry 6 are centrifuged to the inner wall of the pile hole 8 under the action of the spiral guide vane, and most of the sediment slurry 7 is lifted to the orifice of the pile hole 8 as the grouting continues.

[0037] The following is an explanation of the working principle of the device when impacting the pile bottom and lifting the sediment slurry through mechanical analysis.

[0038] 1. Gravity of sediment slurry

[0039] The bottom diameter of bored pile Equivalent to the area of ​​the sediment slurry, assuming the thickness of the sediment slurry is , the density is , then the gravity of the sediment slurry for:

[0040] ①

[0041] in is the acceleration due to gravity.

[0042] 2. Concrete lifting force

[0043] Assume the density of concrete is The injection speed is , then the dynamic pressure of concrete during pouring for:

[0044] ②

[0045] Assume that the area of ​​concrete ejected from the grouting conduit 3 is (take the cross-sectional area of ​​the grouting outlet of the grouting conduit 3), the drag coefficient is , then the drag force exerted by the concrete on the spiral guide vane 2 is for:

[0046] ③

[0047] The drag force The direction is along the extension direction of the spiral guide vane 2. Since the spiral guide vane 2 is provided with a certain guide angle , so the drag force The lifting force decomposed in the vertical direction for:

[0048] ④

[0049] 2. Concrete vortex lift

[0050] Assume that the center radius of the spiral guide vane 2 is , the speed of the concrete vortex is (Unit: revolutions per second), then the tangential velocity of the concrete vortex is (i.e. linear velocity) is:

[0051] ⑤

[0052] Assume the lift coefficient is The effective flow conduction area is (usually taking the vertical projection area of ​​the spiral guide vane 2), the concrete slurry flows on the spiral guide vane 2 to generate vortex lift for

[0053] ⑥

[0054] 3. Comprehensive lifting force of concrete

[0055] Comprehensive lifting force of sediment slurry during concrete pouring For lifting force Vortex lift The sum of

[0056] ⑦

[0057] In order to achieve the purpose of removing the sediment and mud at the bottom of the pile, the following conditions must be met:

[0058] ⑧

[0059] Combining equations ① to ⑧, we get:

[0060] ⑨

[0061] Considering the influence of mud wall protection in actual construction, a correction factor is introduced By correcting the rotation speed of the concrete slurry in the pile hole, equation 9 can be rearranged into

[0062] ⑩

[0063] In this embodiment, the specific coefficient value is: , , , , , , ,

[0064] The concrete spraying area , the guide angle of spiral guide vane 2 , Center radius , effective diversion area , the speed of the concrete vortex , pile bottom diameter and sediment slurry thickness It depends on the specific project. According to the specific size of each component and the injection speed of concrete during construction, if equation ⑩ is established, the pile bottom sediment slurry can be lifted in theory.

[0065] Based on the device, the embodiment of the present invention also provides a method for combined construction of self-cleaning and pouring of cast-in-place piles, comprising the following steps:

[0066] Step 1: Apply wall protection slurry and sediment slurry

[0067] A wall slurry is applied on the inner wall of the pile hole 8 to stabilize the hole wall, and a proper amount of the wall slurry is injected into the pile bottom to mix with the sediment to form the sediment slurry 7. As a mature prior art, the specific construction is not described in detail herein.

[0068] Step 2: Install the device and put it in place

[0069] The steel cage 1 is assembled, and the spiral guide vanes 2 are welded on the periphery to form the guide steel cage. At the same time, the threaded sleeve is installed at the bottom of the grouting conduit 3 through the connecting piece 5 to form the grouting assembly.

[0070] The assembled guide steel cage and grouting assembly are lowered into the pile hole 8 , and an appropriate gap is ensured between the spiral guide vanes 2 and the inner wall of the pile hole 8 .

[0071] Step 3: Pouring and clearing slag

[0072] After the grout outlet of the grouting conduit 3 is located 2 to 15 cm from the pile bottom, the concrete pump is started. The concrete slurry 6 flows at a high speed at the pile bottom, and the upward force and vortex lift formed by the spiral guide vane 2 and the threaded casing 4 flush the sediment slurry 7 at the pile bottom.

[0073] Then, the grouting conduit 3 is continuously lifted up, and the buoyancy provided by the concrete slurry 6 at the bottom to the sediment slurry 7 and the vortex effect generated by the spiral guide vanes 2 are utilized to lift the sediment slurry 7 to the mouth of the pile hole 8 .

[0074] Step 4: Disassemble the Grouting Assembly

[0075] After the grouting is completed, the protrusion 521 on the connecting rod 52 is removed from the clamping groove 513 to separate the grouting conduit 3 and the threaded sleeve 4. The separated grouting assembly is cleaned for turnover use.

[0076] In summary, the embodiment of the present invention combines the basic principles of fluid mechanics, optimizes the structural structure and connection of the self-cleaning and grouting device, and realizes the effective self-removal of the pile bottom sediment in the grouting process of the bored pile. On the one hand, the multi-directional three-dimensional lifting force makes the viscosity of the sediment slurry 7 and the pile bottom more effectively broken, thereby enhancing the slag cleaning effect and improving the construction quality of the pile foundation. On the other hand, thanks to the device, the construction personnel can organically combine the slag cleaning operation with the grouting process, avoiding the separation of the hole cleaning and grouting processes in the traditional process, which is of great significance for simplifying the construction process, reducing construction investment, and improving construction efficiency. In addition, the detachable threaded casing 4 facilitates the disassembly, assembly, turnover and maintenance of the equipment. Therefore, the device and the construction method simultaneously solve the technical problems of incomplete slag cleaning and complicated processes in the traditional process by constructing an innovative pile bottom self-cleaning system, and have high engineering reference significance and broad engineering application prospects.

[0077] For ordinary technicians in this field, although the above-mentioned embodiments are able to better illustrate the technical solutions of the present invention, various changes and improvements can still be made to the structures, parameters and construction methods of each component without departing from the basic ideas of the present invention, and all of these should be considered to be within the protection scope of the present invention.

Claims

1. A self-cleaning and pouring coupling device for cast-in-place piles, characterized in that: It comprises a guide steel cage and a grouting assembly; the grouting assembly is arranged in the guide steel cage and is parallel to or coincident with the axis of the guide steel cage; The guide steel cage includes a steel cage and spiral guide vanes welded to the outer periphery of the steel cage; the spiral guide vanes extend spirally along the height direction of the steel cage to provide lifting force to the flowing concrete slurry and guide it to form a vortex; The grouting assembly includes a grouting conduit, a threaded sleeve and a connecting piece; the threaded sleeve is rotatably connected to the bottom periphery of the grouting conduit through the connecting piece so as to rotate around the axis of the grouting conduit driven by the vortex; the threaded sleeve has a thread structured on the outer surface that matches the spiral extension direction of the spiral guide vane.

2. A self-cleaning and pouring coupling device for bored piles according to claim 1, characterized in that: The grouting conduit is constructed as a threaded structure near the grout outlet.

3. A self-cleaning and pouring coupling device for cast-in-place piles according to claim 1, characterized in that: The spiral guide vanes are arranged throughout the outer circumference of the steel cage.

4. The self-cleaning and pouring coupling device for cast-in-place piles according to claim 1, characterized in that: The spiral guide vane forms a spiral surface with a concave center.

5. The self-cleaning and pouring coupling device for cast-in-place piles according to claim 1, characterized in that: The connecting member comprises a rotating support and a plurality of connecting rods; the rotating support is axially rotatably connected to the grouting conduit; one end of the plurality of connecting rods is detachably connected to the rotating support, and the other end is connected to the top of the threaded casing.

6. A self-cleaning and pouring coupling device for bored piles according to claim 5, characterized in that: The rotating support is provided with a plurality of slots at intervals along the circumference direction, wherein the slots include a countersunk hole provided at the top of the rotating support and a slot communicating with the countersunk hole; The connecting rod enters or exits the clamping slot through the slot; the connecting rod is provided with a protrusion at the top end, the protrusion is placed in the countersunk hole and is limitedly matched with the slot.

7. The self-cleaning and pouring coupling device for bored piles according to claim 5, characterized in that: A circular through cavity is formed in the middle of the rotating support along the thickness direction; a group of bearings are fixedly connected in the circular through cavity; and the inner ring of the bearing is fixed on the surface of the grouting conduit.

8. The self-cleaning and pouring coupling device for bored piles according to claim 1, characterized in that: The pitch of the spiral guide vane is 0.2 to 0.3 times the diameter of the pile hole.

9. The self-cleaning and pouring coupling device for bored piles according to claim 1, characterized in that: The spiral guide vane is made of a steel sheet or plate with a thickness of 5 to 15 mm.

10. A method for construction of a bored pile self-cleaning and pouring, using a bored pile self-cleaning and pouring coupling device according to any one of claims 1 to 9, characterized in that: When pouring concrete, the vortex and lifting force formed by the spiral guide vanes guiding the concrete slurry are used to flush out the sediment slurry at the bottom of the pile hole, and the sediment slurry is lifted to the pile hole mouth by combining the buoyancy of the concrete slurry on the sediment slurry; the vortex drives the threaded casing to rotate to enhance the vortex lift.

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