A center-ribbed prestressed pipe pile for foundation pit support and a construction method thereof

Abstract

The present application relates to the technical field of urban underground engineering, in particular to a center-ribbed prestressed pipe pile for foundation pit support and a construction method thereof, comprising a cross-shaped stiffened-ribbed round steel pipe, a prestressed concrete hollow pipe pile is arranged outside the cross-shaped stiffened-ribbed round steel pipe, and cement mortar is poured between the cross-shaped stiffened-ribbed round steel pipe and the prestressed concrete hollow pipe pile. The present application makes full use of the space of the inner hollow core of the prestressed concrete hollow pipe pile, improves the bending resistance and bending stiffness of the support pile under the condition of the same pipe pile outer diameter, and avoids more serious soil squeezing effect caused by larger diameter pipe piles; the cross-shaped stiffened-ribbed round steel pipe can be recycled and reused, thereby significantly reducing the engineering cost.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of urban underground engineering, in particular to a center-ribbed prestressed pipe pile for foundation pit support and a construction method thereof. BACKGROUND

[0002] The prefabricated prestressed hollow concrete pipe pile has the characteristics of high pile strength, low cost, reliable quality, fast construction, clean site and no environmental pollution, and has been widely used in foundation pit support engineering.

[0003] At present, deformation control is often used in the design of foundation pit support, and the bending resistance and bending stiffness of the pile body are important design indicators. When the design of foundation pit support encounters poor site soil conditions or deep design depth, larger diameter pipe piles are often selected to improve the mechanical parameters for use as foundation pit support piles. However, large-diameter pipe piles will cause difficulties in pile transportation on the construction site and produce more serious soil squeezing effect, which will endanger the existing pipe piles and surrounding buildings and structures. At the same time, the hollow space in the middle of the pipe pile is wasted and no building materials are provided to improve the mechanical parameters of the pile body. Therefore, we improve it and propose a center-ribbed prestressed pipe pile for foundation pit support and a construction method thereof. SUMMARY

[0004] The present application provides a center-ribbed prestressed pipe pile for foundation pit support and a construction method thereof, which comprises a cross-shaped stiffening rib round steel pipe, the outer part of the cross-shaped stiffening rib round steel pipe is provided with a prestressed concrete hollow pipe pile, and cement mortar is poured between the cross-shaped stiffening rib round steel pipe and the prestressed concrete hollow pipe pile; the cross-shaped stiffening rib round steel pipe is composed of a misalignment prevention support ring, a round steel pipe, a bolt and an inserted cross-shaped internal stiffening assembly, and the misalignment prevention support ring, the round steel pipe and the inserted cross-shaped internal stiffening assembly are connected by bolts; the misalignment prevention support ring is welded by a steel ring and a steel support, and the inserted cross-shaped internal stiffening assembly comprises a cross-shaped internal stiffening plate and four arc-shaped side plates provided with a plurality of bolt holes, and the four arc-shaped side plates are respectively welded to the end face of the cross-shaped internal stiffening plate.

[0005] As a preferred technical solution of the present application, the central axis of the round steel pipe and the central axis of the inserted cross-shaped internal stiffening assembly are coincident with the central axis of the prestressed concrete hollow pipe pile.

[0006] As a preferred technical solution of the present application, the top end and the bottom end of the round steel pipe are provided with misalignment prevention support rings, and one end of the steel support is in contact with the inner side surface of the prestressed concrete hollow pipe pile.

[0007] As a preferred technical scheme of the present application, the bolt holes are arranged in double rows at equal intervals in the vertical direction on the circular arc side plate, and bolt holes are also arranged on the circular steel pipe and the steel circular ring, and the bolt holes on the circular steel pipe and the steel circular ring correspond to the bolt holes on the circular arc side plate.

[0008] As a preferred technical scheme of the present application, the cross-shaped inner stiffening plate is composed of two short inner stiffening plates and one long inner stiffening plate, the long inner stiffening plate is arranged in the middle, and the two short inner stiffening plates are orthogonally aligned with the long inner stiffening plate and welded on the long inner stiffening plate.

[0009] As a preferred technical scheme of the present application, the distance from the end of the steel top support away from the steel circular ring to the center of the steel circular ring is greater than the outer diameter of the steel circular ring.

[0010] As a preferred technical scheme of the present application, the circular steel pipe is a circular steel pipe with a ratio of outer diameter to wall thickness less than 50, the prestressed concrete hollow core pipe pile is a prestressed concrete hollow core pipe pile with an outer diameter greater than 700 mm, and the cement mortar is composed of cement, fine aggregate and water in a ratio of 1:3:0.65.

[0011] As a preferred technical scheme of the present application, the method comprises the following steps:

[0012] Step one: prefabricate the anti-misalignment support ring, the circular steel pipe, the plug-in cross-shaped inner stiffening assembly and the prestressed concrete hollow core pipe pile in the factory and transport them to the construction site;

[0013] Step two: assemble the anti-misalignment support ring, the circular steel pipe, the bolt and the plug-in cross-shaped inner stiffening assembly into a cross-shaped stiffening rib circular steel pipe at the construction site;

[0014] Step three: apply a friction-reducing agent to the outer wall of the cross-shaped stiffening rib circular steel pipe;

[0015] Step four: use the pile sinking process to construct the prestressed concrete hollow core pipe pile at the pile body point position at the construction site;

[0016] Step five: hoist the plug-in cross-shaped inner stiffening assembly into the hollow core part of the prestressed concrete hollow core pipe pile;

[0017] Step six: inject cement mortar into the gap between the plug-in cross-shaped inner stiffening assembly and the prestressed concrete hollow core pipe pile;

[0018] Step seven: after the overall construction of the foundation pit project is completed, the cross-shaped stiffening rib circular steel pipe is recovered.

[0019] The application makes full use of the space of the hollow core of the prestressed concrete hollow pipe pile, improves the bending resistance and bending stiffness of the supporting pile under the condition of the same pipe pile outer diameter, and avoids more serious soil squeezing effect caused by larger diameter pipe piles.

[0020] The cross-shaped stiffening rib round steel pipe in the application can be recycled and reused, thereby significantly reducing the engineering cost. BRIEF DESCRIPTION OF DRAWINGS

[0021] The accompanying drawings are included to provide a further understanding of the application and are incorporated in and constitute a part of this specification, illustrate embodiments of the application and are used to explain the application, and do not constitute a limitation of the application. In the drawings:

[0022] Figure 1 is a schematic diagram of the overall structure of the application;

[0023] Figure 2 is a schematic diagram of the plane structure of the cross-shaped stiffening rib round steel pipe in the application;

[0024] Figure 3 is a schematic diagram of the plane structure of the plug-in cross-shaped internal stiffening assembly in the application;

[0025] Figure 4 is a schematic diagram of the plane structure of the anti-misplacement support ring in the application;

[0026] Figure 5 is a schematic diagram of the front structure of the cross-shaped stiffening rib round steel pipe in the application;

[0027] Figure 6 is a schematic diagram of the front structure of the plug-in cross-shaped internal stiffening assembly in the application;

[0028] Figure 7 is a schematic diagram of the flow structure in the application.

[0029] In the drawings: 1, cross-shaped stiffening rib round steel pipe; 11, anti-misplacement support ring; 111, steel round ring; 112, steel support; 12, round steel pipe; 13, bolt; 14, plug-in cross-shaped internal stiffening assembly; 141, cross-shaped internal stiffening plate; 142, arc-shaped side plate; 2, prestressed concrete hollow pipe pile; 3, cement mortar. DETAILED DESCRIPTION

[0030] The preferred embodiments of the application are described below in conjunction with the accompanying drawings, and it should be understood that the preferred embodiments described herein are only used to illustrate and explain the application, and do not limit the application.

[0031] Embodiment: as Figure 1As shown, the present application is a kind of center rib prestressed pipe pile for foundation pit support, including cross stiffener round steel pipe 1, cross stiffener round steel pipe 1 outside is provided with prestressed concrete hollow core pipe pile 2, and cross stiffener round steel pipe 1 and prestressed concrete hollow core pipe pile 2 between pouring cement mortar 3. By setting cross stiffener round steel pipe 1 in prestressed concrete hollow core pipe pile 2, not only can make full use of the space in prestressed concrete hollow core pipe pile 2, but also can strengthen the bending capacity and bending stiffness of prestressed concrete hollow core pipe pile 2, thereby avoiding more serious soil squeezing effect caused by larger diameter pipe pile.

[0032] As shown, Figures 2-6 Cross stiffener round steel pipe 1 is composed of anti-misplacement support ring 11, round steel pipe 12, bolt 13 and plug-in cross type inner stiffening assembly 14, anti-misplacement support ring 11, round steel pipe 12 and plug-in cross type inner stiffening assembly 14 are connected by bolt 13, so as to facilitate subsequent disassembly and recycling. Anti-misplacement support ring 11 is welded by steel ring 111 and steel support 112, plug-in cross type inner stiffening assembly 14 includes cross type inner stiffening plate 141 and four arc type side plates 142 provided with a plurality of bolt holes, and the four arc type side plates 142 are welded on the end face of cross type inner stiffening plate 141. Anti-misplacement support ring 11 and plug-in cross type inner stiffening assembly 14 can enhance the bending capacity of prestressed concrete hollow core pipe pile 2.

[0033] As shown, Figure 2 And Figure 4 The center axis of round steel pipe 12 and the center axis of plug-in cross type inner stiffening assembly 14 coincide with the center axis of prestressed concrete hollow core pipe pile 2, which enhances the balance of the whole. The top end and the bottom end of round steel pipe 12 are provided with anti-misplacement support ring 11, which can prevent misplacement during installation. One end of steel support 112 is in contact with the inner side of prestressed concrete hollow core pipe pile 2, and cement mortar 3 is poured in the gap between steel ring 111 and prestressed concrete hollow core pipe pile 2 through the contact of the two, so as to enhance the tightness of the connection between the two.

[0034] Bolt holes are arranged in vertical direction on arc type side plate 142, and bolt holes are also arranged on round steel pipe 12 and steel ring 111, and the bolt holes on round steel pipe 12 and steel ring 111 correspond to the bolt holes on arc type side plate 142. The bolt holes are fixed by bolt 13, so as to facilitate recycling after disassembly.

[0035] As shown, Figure 3As shown, the cross-shaped inner stiffened plate 141 is composed of two short inner stiffened plates and one long inner stiffened plate, the long inner stiffened plate is centrally arranged, the two short inner stiffened plates are orthogonally aligned with the long inner stiffened plate and welded on the long inner stiffened plate, the cross-shaped inner stiffened plate 141 arranged can connect multiple arc-shaped side plates 142 together, so as to facilitate the assembly of the arc-shaped side plate 142 and the steel ring 111.

[0036] As shown in Figure 1 and Figure 4 As shown, the distance from the end of the steel brace 112 away from the steel ring 111 to the center of the steel ring 111 is greater than the outer diameter of the steel ring 111. The circular steel pipe 12 is a circular steel pipe 12 with an outer diameter to wall thickness ratio of less than 50, such as a circular steel pipe 12 with a ratio of 45, which has higher bending strength and bending stiffness. The prestressed concrete hollow pipe pile 2 selects a prestressed concrete hollow pipe pile 2 with an outer diameter greater than 700mm, wherein the hollow part can place a large-diameter cross-shaped stiffened rib circular steel pipe 1, which has large cross-sectional size, resulting in large cross-sectional moment of inertia, which is beneficial to the bending performance of the material. The cement mortar 3 is composed of cement, fine aggregate and water in a ratio of 1:3:0.65, and the cement mortar 3 can increase the adhesion between the cross-shaped stiffened rib circular steel pipe 1 and the prestressed concrete hollow pipe pile 2, and enhance the stability during use.

[0037] As shown in Figure 7 A center-ribbed prestressed pipe pile construction method for foundation pit support, comprising the following steps:

[0038] Step one: precast anti-misplacement support ring 11, circular steel pipe 12, plug-in cross-shaped inner stiffening assembly 14 and prestressed concrete hollow pipe pile 2 in the factory and transport to the construction site.

[0039] Step two: assemble the anti-misplacement support ring 11, circular steel pipe 12, bolt 13 and plug-in cross-shaped inner stiffening assembly 14 into a cross-shaped stiffened rib circular steel pipe 1 at the construction site, specifically, the anti-misplacement support ring 11 is located on the surface of the circular steel pipe 12, the plug-in cross-shaped inner stiffening assembly 14 is located inside the circular steel pipe 12, and the bolt holes on the circular steel pipe 12, the arc-shaped side plate 142 and the steel ring 111 are corresponded, and the three are fixed by the bolt 13.

[0040] Step three: apply friction-reducing agent to the outer wall of the cross-shaped stiffened rib circular steel pipe 1, which can reduce frictional resistance and mechanical wear.

[0041] Step four: use pile sinking process to construct prestressed concrete hollow pipe pile 2 at the pile body point position at the construction site, first fix the prestressed concrete hollow pipe pile 2, and then put the cross-shaped stiffened rib circular steel pipe 1 into the inside of the prestressed concrete hollow pipe pile 2.

[0042] Step five: the cross stiffening rib round steel pipe 1 is hung in the hollow part of the prestressed concrete hollow pipe pile 2, and the cross stiffening rib round steel pipe 1 should be kept in a vertical state during the hanging process to prevent the anti-misalignment support ring 11 from scratching the inner wall of the prestressed concrete hollow pipe pile 2 and causing damage.

[0043] Step six: the cement mortar 3 is injected into the gap between the cross stiffening rib round steel pipe 1 and the prestressed concrete hollow pipe pile 2, and a guide pipe can be used to inject the cement mortar 3 from the bottom of the prestressed concrete hollow pipe pile 2, which facilitates construction and ensures the compactness of the cement mortar 3.

[0044] Step seven: after the overall construction of the foundation pit project is completed, the cross stiffening rib round steel pipe 1 is recovered, thereby reducing the cost of the project.

[0045] The present application makes full use of the cross stiffening rib round steel pipe 1 placed in the hollow position inside the prestressed concrete hollow pipe pile 2, which not only makes full use of the space of the hollow position of the prestressed concrete hollow pipe pile 2, but also improves the bending resistance and bending stiffness of the supporting pile under the condition of the same pipe pile outer diameter, thereby avoiding more serious soil squeezing effect caused by larger diameter pipe piles.

[0046] In the description of the present application, it should be noted that the terms "vertical", "upper", "lower", "horizontal" and the like indicate the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the present application.

[0047] In the description of the present application, it should be noted that unless otherwise specified and limited, the terms "set", "mount", "connected", "connected" should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or indirectly connected through an intermediate medium; it can be the communication between two elements inside. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0048] Finally, it should be noted that: the above only describes the preferred embodiments of the present application and is not intended to limit the present application, although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for some technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A construction method for a central ribbed prestressed pipe pile for foundation pit support, comprising a cross-shaped stiffening rib circular steel pipe (1), a prestressed concrete hollow pipe pile (2) being arranged outside the cross-shaped stiffening rib circular steel pipe (1), and cement mortar (3) being poured between the cross-shaped stiffening rib circular steel pipe (1) and the prestressed concrete hollow pipe pile (2); the cross-shaped stiffening rib circular steel pipe (1) is composed of an anti-dislocation support ring (11), a round steel pipe (12), bolts (13), and an inserted cross-shaped inner stiffening assembly (14). The anti-dislocation support ring (11), the round steel pipe (12) and the inserted cross-shaped internal stiffening assembly (14) are all connected by bolts (13); the anti-dislocation support ring (11) is welded by a steel circular ring (111) and a steel top support (112); the inserted cross-shaped internal stiffening assembly (14) includes a cross-shaped internal stiffening plate (141) and four arc-shaped side plates (142) provided with a plurality of bolt holes; the four arc-shaped side plates (142) are respectively welded to the end faces of the cross-shaped internal stiffening plate (141); Anti-dislocation support rings (11) are provided at the top and bottom ends of the circular steel tube (12), and one end of the steel top support (112) contacts the inner side surface of the prestressed concrete hollow pipe pile (2); The bolt holes are arranged in double rows at equal intervals in the vertical direction on the arc-shaped side plate (142), and bolt holes are also provided on the round steel tube (12) and the steel ring (111), and the bolt holes on the round steel tube (12) and the steel ring (111) correspond to the bolt holes on the arc-shaped side plate (142), characterized in that: The following steps are involved: Step 1: Prefabricate the anti-dislocation support ring (11), the round steel pipe (12), the inserted cross-shaped internal reinforcement component (14) and the prestressed concrete hollow pipe pile (2) in the factory and transport them to the construction site; Step 2: Assemble the anti-dislocation support ring (11), the round steel pipe (12), the bolts (13) and the inserted cross-shaped internal reinforcement assembly (14) into a cross-shaped stiffening rib round steel pipe (1) at the construction site; Step 3: Apply a friction reducer to the outer wall of the cross-shaped stiffening rib circular steel pipe (1); Step 4: constructing prestressed concrete hollow pipe piles (2) at the pile body points at the construction site using the pile sinking process; Step 5: Hanging a cross-shaped stiffening rib circular steel pipe (1) into the hollow portion of the prestressed concrete hollow pipe pile (2); Step 6: pouring cement mortar (3) into the gap between the cross-shaped stiffening rib circular steel pipe (1) and the prestressed concrete hollow pipe pile (2); Step 7: After the overall construction of the foundation pit is completed, the cross-shaped stiffening rib circular steel pipe (1) is recovered.

2. The construction method of a central ribbed prestressed pipe pile for foundation pit support according to claim 1, characterized in that: The central axis of the circular steel pipe (12) and the central axis of the inserted cross-shaped internal reinforcement component (14) both coincide with the central axis of the prestressed concrete hollow pipe pile (2).

3. The construction method of a central ribbed prestressed pipe pile for foundation pit support according to claim 1, characterized in that: The cross-shaped inner stiffening plate (141) is composed of two short inner stiffening plates and one long inner stiffening plate, the long inner stiffening plate is centrally arranged, and the two short inner stiffening plates are orthogonally aligned with the long inner stiffening plate and welded to the long inner stiffening plate.

4. The construction method of a central ribbed prestressed pipe pile for foundation pit support according to claim 1, characterized in that: The distance between one end of the steel top support (112) away from the steel circular ring (111) and the center of the steel circular ring (111) is greater than the outer diameter of the steel circular ring (111).

5. The construction method of a central ribbed prestressed pipe pile for foundation pit support according to claim 1, characterized in that: The round steel pipe (12) is a round steel pipe (12) having an outer diameter to wall thickness ratio of less than 50, the prestressed concrete hollow pipe pile (2) is a prestressed concrete hollow pipe pile (2) having an outer diameter greater than 700 mm, and the cement mortar (3) is composed of cement, fine aggregate and water in a ratio of 1:3:0.65.

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