Double-steel-casing structure of underwater pile foundation

Abstract

The invention relates to the technical field of pile foundations, and particularly discloses an underwater pile foundation double-steel pile casing structure which comprises an outer pile casing, an inner pile casing and a drainage assembly. The outer pile casing is sleeved on the periphery of the inner pile casing; the drainage assembly comprises a plurality of drainage tubes and ribs; the plurality of drainage tubes are circumferentially and uniformly distributed around the outer pile casing; the drainage tube is attached to the outer wall of the outer protective cylinder; a drainage channel is arranged in the drainage tube; an inlet and an outlet of the drainage channel face the circumferential direction of the outer protection cylinder and are opposite in direction. A plurality of ribs are arranged in the area, covered by the drainage tube, of the periphery of the outer pile casing; the ribs are arranged in the flowing direction of the drainage channel. A preset buried line is arranged on the outer protective cylinder; and the buried line passes through the lower part of the drainage tube. In the embodiment, water flow can flow in through the drainage channel facing the water flow direction, the flowing-in liquid can flow along a fixed path, the disordered state of natural diffusion of the water flow is replaced, the situation that the water flow surrounds the periphery of the outer protection barrel to form streaming is avoided, and the effect of vortex-induced force is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pile foundation, in particular to a double-steel-casing structure of underwater pile foundation. BACKGROUND

[0002] The underwater pile foundation is a structure that can be used in underground continuous wall, caisson bottom sealing, underwater tunnel and other scenarios to play a supporting role. Its core requirement is to realize the dense pouring of concrete in the underwater environment to avoid defects such as segregation, honeycomb and fault. During construction, the steel casing can be used as an auxiliary tool for pile foundation construction to protect the pile hole and maintain the stability of the construction environment.

[0003] During operation, the steel casing needs to be buried in the soil. However, the actual underwater soil / substrate environment is complex, and the steel casing will be disturbed by many factors. For example, in areas with turbulent water flow, the water flow will form a flow around the outer periphery of the casing, causing alternating vortices on the outer periphery of the casing, thereby generating periodic vortex-induced forces, causing the casing to vibrate laterally. The vibration caused by vortex-induced forces can cause fatigue damage to the casing structure, destroy the embedded relationship between the casing and the surrounding soil, and affect the overall stiffness. SUMMARY

[0004] Therefore, the purpose of the present application is to provide a double-steel-casing structure of underwater pile foundation to solve some or all of the above problems.

[0005] To achieve the above technical purpose, the present application provides a double-steel-casing structure of underwater pile foundation, comprising: an outer casing, an inner casing and a drainage assembly. The outer casing is sleeved on the outer periphery of the inner casing. The drainage assembly comprises a plurality of drainage pipes and ribs. The plurality of drainage pipes are uniformly distributed around the outer periphery of the outer casing. The drainage pipes are arranged in close contact with the outer wall of the outer casing. The drainage pipes are provided with a drainage channel. The inlet and outlet of the drainage channel are both directed towards the circumference of the outer casing, and the directions are opposite. The outer periphery of the outer casing is provided with a plurality of ribs in the area covered by the drainage pipes. The ribs are arranged along the flow direction of the drainage channel. The outer casing is provided with a predetermined burial line. The burial line passes through the lower part of the drainage pipe.

[0006] Further, the length of the rib is less than the length of the drainage channel.

[0007] Further, the rib is arranged at the upstream inlet segment of the drainage channel.

[0008] Further, the rib is arranged at a downstream outlet section of the drainage channel.

[0009] Further, a height of an outlet of the drainage channel is less than a height of an inlet of the drainage channel, so that the fluid in the drainage channel flows upwardly; The outlet of the drainage channel is located above the burial line.

[0010] Further, along an axial direction of the outer casing, a distribution density of the ribs increases.

[0011] Further, an included angle between the inlet and the outlet of the drainage channel with respect to the axial direction of the outer casing is less than 60°.

[0012] Further, an inner periphery of the outer casing is provided with a protrusion; The protrusion abuts against the inner casing.

[0013] Further, a thickness of the drainage pipe along a radial direction of the outer casing decreases from top to bottom.

[0014] Further, the outer casing comprises a plurality of sub-casings; The plurality of sub-casings are sequentially spliced by a flange structure.

[0015] As can be seen from the above technical solutions, the application provides a double-steel-casing structure of an underwater pile foundation, which comprises an outer casing, an inner casing and a drainage assembly; the outer casing is sleeved on an outer periphery of the inner casing; the drainage assembly comprises a plurality of drainage pipes and ribs; the plurality of drainage pipes are uniformly distributed in a circumferential direction of the outer casing; the drainage pipes are arranged in close contact with an outer wall of the outer casing; the drainage pipes are provided with drainage channels; the inlet and the outlet of the drainage channels are both directed towards the circumferential direction of the outer casing and are oppositely directed; a region of the outer periphery of the outer casing covered by the drainage pipes is provided with a plurality of ribs; the ribs are arranged along a flow direction of the drainage channels; the outer casing is provided with a preset burial line; and the burial line passes through a lower part of the drainage pipes.

[0016] In the embodiment, the drainage channels directed towards the water flow direction can allow the water flow to flow in, so that the flowed-in liquid flows along a fixed path to replace the disordered state of natural diffusion of the water flow, avoid the water flow around the outer periphery of the outer casing to form a flow around, and realize the reduction of the influence of the vortex-induced force. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without any creative effort.

[0018] Figure 1 A plan view of an outer pile casing and an inner pile casing of a double-steel casing structure of an underwater pile foundation provided by an embodiment of the present application; Figure 2 A partial side view perspective of a double-steel casing structure of an underwater pile foundation provided by an embodiment of the present application. DETAILED DESCRIPTION

[0019] The technical solutions of the embodiments of the present application will be described clearly and completely below with reference to the drawings. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative work fall within the scope of the present application.

[0020] In the description of the embodiments of the present application, it should be noted that the orientations or positional relationships indicated by the terms “center”, “upper”, “lower”, “left”, “right”, “vertical”, “horizontal”, “inner”, “outer” and the like are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of describing the embodiments of the present application and simplifying the description, and therefore cannot be understood as indicating or implying that the devices or elements must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation on the embodiments of the present application. In addition, the terms “first”, “second”, “third” are only for the purpose of description, and cannot be understood as indicating or implying relative importance.

[0021] In the description of the embodiments of the present application, it should be noted that unless otherwise explicitly specified and limited, the terms “mounting”, “connection”, “connecting” should be understood in a broad sense, for example, can be fixedly connected, or replaceably connected, or integrally connected, can be mechanically connected, or electrically connected, can be directly connected, or indirectly connected through an intermediate medium, can be internal communication of two elements. Those skilled in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific circumstances.

[0022] Please refer to Figure 1 With Figure 2The underwater pile double-steel casing structure provided in the embodiments of the present application comprises: an outer casing 10, an inner casing 20, and a drainage assembly 30; the outer casing 10 is sleeved on the outer periphery of the inner casing 20; the drainage assembly 30 comprises: a plurality of drainage pipes 31 and ribs 33; the plurality of drainage pipes 31 are uniformly distributed in a circle around the outer casing 10; the drainage pipes 31 are arranged in close contact with the outer wall of the outer casing 10; the drainage pipes 31 are internally provided with drainage channels 32; the inlet and outlet of the drainage channels 32 are both directed towards the circumference of the outer casing 10 and are oppositely directed; a plurality of ribs 33 are arranged on the region of the outer periphery of the outer casing 10 covered by the drainage pipes 31; the ribs 33 are arranged along the flow direction of the drainage channels 32; a preset burial line a is arranged on the outer casing 10; the burial line a passes through the lower part of the drainage pipes 31.

[0023] In actual application, the vortex-induced force refers to the wake flow separation phenomenon caused by the flow around the casing. Specifically, when the water flow flows along the casing wall to the tail, due to the consumption of kinetic energy and the sudden drop in pressure, the fluid cannot continue to adhere to the wall and will separate from the wall and form alternating vortices at the tail. When the vortices periodically fall off, they will generate transverse alternating forces on the casing, which are vortex-induced forces.

[0024] In the embodiments, the drainage pipes 31 are uniformly distributed in a circle, and the drainage pipes 31 directed towards the water flow can supply the water flow to flow in, thereby playing a role of active drainage, reducing the formation of wake flow separation and vortices, and thereby reducing the influence of the vortex-induced force.

[0025] Specifically, the drainage channels 32 directed towards the water flow will preferentially accept the oncoming flow, thereby leading the part of the flow originally flowing around the outer casing 10 to flow into the inside of the drainage channels 32, reducing the amount of fluid participating in the wake flow separation, thereby reducing the energy of the vortices and further reducing the vortex-induced force; the fluid led out by the drainage channels 32 will form a mixed flow with the originally flowing fluid, thereby disrupting the originally formed regular alternating wake flow vortices, reducing the destructive nature of the vortex-induced force, and avoiding the risk of resonance. Although the drainage channels 32 directed towards the side of the water flow cannot supply the water flow to flow in, on the one hand, they can increase the outer periphery diameter of the outer casing 10 and increase the contact surface with the soil layer to enhance the stability, and on the other hand, they can prevent the formation of the flow around the casing, and thus can also play a role in inhibiting the vortex-induced force.

[0026] In the embodiments, the outer casing 10 is buried in the soil according to the burial line a, that is, the length from the bottom of the outer casing 10 to the burial line a is the burial depth of the outer casing 10. In actual application, the position of the burial line a can be obtained according to software simulation calculation or the burial of other casing structures, and then the setting position of the drainage assembly 30 is configured according to the data obtained by calculation or actual burial.

[0027] As an implementation manner, the outer casing 10 can be configured to comprise a plurality of sub-casings; the plurality of sub-casings are sequentially spliced through flange structures.

[0028] The flange structure is used to splice multiple sub-cylinders, which is a conventional connection method and can adjust the length of the outer protection cylinder 10 according to the actual water depth and burial depth. In this embodiment, the drainage assembly 30 can be arranged on a sub-cylinder. After obtaining the position data of the burial line a by the above method, the sub-cylinder provided with the drainage assembly 30 is used as the sub-cylinder provided with the burial line a.

[0029] In practical applications, the outer protection cylinder 10 can include multiple sub-cylinders provided with the drainage assembly 30, that is, multiple drainage assemblies 30 are arranged along the outer periphery of the outer protection cylinder 10 in the axial direction.

[0030] In this embodiment, the drainage assembly 30 is crossed by the burial line a, that is, after the outer protection cylinder 10 is buried in the soil, the drainage assembly 30 can be located near the soil layer. On the one hand, the vibration near the soil layer has a great impact on the protection cylinder structure, and on the other hand, when the water flow impacts the junction of the outer protection cylinder 10 and the soil, the soil will be washed away by the water flow, so that the outer protection cylinder 10 will sink or loosen. In this scheme, part of the drainage channels 32 in the drainage assembly 30 can play a flow-around role to reduce the impact of the water flow on the soil, and part of the drainage channels 32 can introduce the water flow originally impacting the soil to reduce the impact of the water flow on the soil. At the same time, the above-mentioned effect of reducing the vortex energy can also reduce the influence of the vortex flow on the soil surface silt, weaken the vortex-induced force of the soil layer component, and reduce the vibration disturbance of the outer protection cylinder 10 to the peripheral soil.

[0031] As an improved way, the height of the outlet of the drainage channel 32 is less than the height of the inlet of the drainage channel 32, so that the fluid in the drainage channel 32 flows upward; the outlet of the drainage channel 32 is located above the burial line a.

[0032] That is, in this embodiment, the water entering the drainage channel 32 will flow upward, which can avoid the accumulation of silt in the drainage channel 32, and can also avoid the direct impact of the water flow from the outlet of the drainage channel 32 on the soil.

[0033] At the same time, the ribs 33 provided in this scheme can play a flow guiding role to avoid the liquid entering the drainage channel 32 from moving around in the drainage channel 32, so as to better guide the turbulent flow to laminar flow and further reduce the turbulence intensity. On the other hand, the ribs 33 are arranged on the outer periphery of the outer protection cylinder 10, which can enhance the strength of the outer protection cylinder 10.

[0034] As an implementation, the length of the rib 33 is less than the length of the drainage channel 32, which can avoid the redundant resistance and excessive disturbance caused by full-flow channel arrangement.

[0035] Specifically, the drainage channel 32 includes an upstream inlet section, a middle flow section, and a downstream outlet section.

[0036] When the water flow velocity is large, the ribs 33 can be arranged at the upstream inlet section of the flow guide channel 32 to reduce the initial water flow energy and suppress the generation of vortexes in the initial stage, while helping to generate a stable flow field downstream (downstream outlet section).

[0037] When the water flow velocity is small, the ribs 33 are arranged at the downstream outlet section of the flow guide channel 32 to reduce the inlet resistance of the flow guide channel 32 and help to establish a stable flow state.

[0038] It should be noted that through the flow guide assembly 30 provided in the embodiment, workers in the field can use existing simulation software to simulate the setting length and setting position of the ribs 33 according to the water flow velocity, the outer diameter of the outer casing 10, the inlet size of the flow guide channel 32, and the size of the ribs 33, and obtain the water flow velocity at which the ribs 33 are suitable for being arranged at the upstream inlet section / downstream outlet section through a limited number of simulations. Therefore, the specific water flow velocity threshold is not described in detail in the embodiment.

[0039] In one embodiment, the arrangement density of the ribs 33 increases along the axial direction of the outer casing 10.

[0040] In the embodiment, the ribs 33 on the lower side have a higher density and can quickly break the vortexes; the ribs 33 on the upper side have a lower density and help the water flow to pass through to form a stable flow field.

[0041] In Figure 2 In the structural diagram shown, in order to facilitate the display of the structure of the flow guide assembly 30, the flow guide channel 32 is configured to have a large arc angle.

[0042] In one embodiment provided in the present application, the included angle between the inlet and outlet of the flow guide channel 32 with respect to the axial direction of the outer casing 10 is less than 60°.

[0043] Specifically, the included angle between the inlet and outlet of the flow guide channel 32 with respect to the axial direction of the outer casing 10 is less than 60°, which can reduce the turning angle of the fluid entering the flow guide channel 32, thereby helping to form a more stable flow field.

[0044] In one embodiment, the inner periphery of the outer casing 10 is provided with a protrusion 11; the protrusion 11 abuts against the inner casing 20.

[0045] The protrusion 11 can increase the stability of the inner casing 20 and reduce the risk of shaking of the inner casing 20.

[0046] In one embodiment, the thickness of the flow guide pipe 31 along the radial direction of the outer casing 10 decreases from top to bottom, which helps the outer casing 10 to be buried in the soil during the pressing process.

[0047] The above are preferred embodiments of the present application, and are not used to limit the present application, and for those skilled in the art, the aforementioned examples can be modified, or some technical features can be replaced by equivalent, but any modification, equivalent replacement, improvement, etc. within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. An underwater pile foundation double steel casing structure, characterized in that: include: An outer casing (10), an inner casing (20) and a drainage assembly (30); The outer casing (10) is sleeved on the outer circumference of the inner casing (20); The drainage assembly (30) comprises: a plurality of drainage tubes (31) and ribs (33); The plurality of drainage tubes (31) are evenly distributed around the outer casing (10); The drainage tube (31) is arranged in contact with the outer wall of the outer casing (10); A drainage channel (32) is provided in the drainage tube (31); The inlet and outlet of the drainage channel (32) are both oriented toward the circumference of the outer casing (10) and in opposite directions; A plurality of ribs (33) are provided on the outer periphery of the outer casing (10) in an area covered by the drainage tube (31); The ribs (33) are arranged along the flow direction of the drainage channel (32); The outer casing (10) is provided with a preset burying line (a); The buried line (a) passes through the lower part of the drainage tube (31).

2. The underwater pile foundation double steel casing structure according to claim 1 is characterized in that: The length of the rib (33) is smaller than the length of the drainage channel (32).

3. The underwater pile foundation double steel casing structure according to claim 2 is characterized in that: The ribs (33) are arranged at the upstream inlet section of the drainage channel (32).

4. The underwater pile foundation double steel casing structure according to claim 1 is characterized in that: The ribs (33) are arranged at the downstream outlet section of the drainage channel (32).

5. The underwater pile foundation double steel casing structure according to claim 1 is characterized in that: The height of the outlet of the drainage channel (32) is smaller than the height of the inlet of the drainage channel (32), so that the fluid in the drainage channel (32) flows upward; The outlet of the drainage channel (32) is located above the buried line (a).

6. The underwater pile foundation double steel casing structure according to claim 1 is characterized in that: Along the axial direction of the outer casing (10), the arrangement density of the ribs (33) increases gradually.

7. The underwater pile foundation double steel casing structure according to claim 1 is characterized in that: The included angle between the inlet and the outlet of the drainage channel (32) with respect to the axial direction of the outer casing (10) is less than 60°.

8. The underwater pile foundation double steel casing structure according to claim 1 is characterized in that: The inner periphery of the outer casing (10) is provided with a protrusion (11); The protrusion (11) abuts against the inner casing (20).

9. The underwater pile foundation double steel casing structure according to claim 1, characterized in that: The thickness of the drainage tube (31) decreases from top to bottom along the radial direction of the outer casing (10).

10. The underwater pile foundation double steel casing structure according to claim 1, characterized in that: The outer casing (10) comprises a plurality of sub-tubes; The plurality of sub-tubes are sequentially spliced ​​together through a flange structure.

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