Steel pile tip capable of reducing soil squeezing effect of tubular pile
By adopting a combined structure of outer vertical ring plate, inner conical ring plate and stiffening plate at the tip of the pipe pile, the soil cross-sectional area of the pile tip is increased, and the problem of low soil extraction rate of the middle excavation method is solved, which significantly increases the amount of soil extraction and reduces the soil extraction effect during the pile sinking process of the pipe pile.
Patent Information
- Application Number
- CN202421953192.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-08-13
- Publication Date
- 2025-05-23
- Estimated Expiration
- 2034-08-13
AI Technical Summary
In the prior art, the soil extraction rate is relatively low during the excavation and introduction method, resulting in a high soil extraction effect during the pipe pile sinking process, affecting the effectiveness of reducing the soil extrusion effect of the pipe pile.
A steel pile tip structure including an outer vertical ring plate, an inner conical ring plate and a stiffening plate is adopted. The outer vertical ring plate is fixed at the bottom of the end plate of the pipe pile, and the inner conical ring plate is placed in the cavity of the outer vertical ring plate, and the structural connection is enhanced by the stiffening plate to form a conical shaped cavity space with "small upper and larger lower lower" to increase the soil cross-sectional area of the pile tip.
By increasing the cross-sectional area of the pile tip, the soil cut-off rate increased from 0.74 to 0.96 in actual tests, and the soil cut-off rate of the meshes increased from 32% to 90%, which greatly increased the amount of soil cut-off and effectively reduced the soil cut-off effect during the pile sinking of pipe piles.
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Figure CN222893622U_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the technical field of pile foundation engineering, and in particular to a steel pile tip for reducing the soil squeezing effect of a pipe pile. Background Art
[0002] Prestressed concrete pipe piles are increasingly widely used in the field of engineering construction due to their advantages such as high pile body strength, factory prefabrication, stable quality, mud-free construction, and fast construction speed, and are gradually showing a trend of replacing traditional cast-in-place piles.
[0003] At the same time, the direct construction methods of conventional hammer pile driving and static pressure pile driving cause the soil squeezing effect of pipe piles during the pile driving process. The soil squeezing effect will cause the following two adverse effects on the soil: the increase of pore water pressure and the displacement of soil. The combined effect of the two can easily lead to the displacement and floating of the constructed piles, causing harm to the foundations of nearby existing structures and underground pipelines. At present, various pile driving methods for reducing the soil squeezing effect of pipe piles have emerged in an endless stream, but due to factors such as their uneconomical cost and low construction efficiency, there are certain difficulties in actual promotion. Conventional hole-driving methods, stress release holes, pressure relief grooves and other measures are still technically feasible, economical and effective methods to solve the soil squeezing effect of pipe piles. The utility model is mainly suitable for using the mid-excavation hole-driving method to reduce the soil squeezing effect of pipe piles during static pressure pile driving.
[0004] The hole-guiding method is divided into the pre-guiding hole method and the mid-excavation hole-guiding method according to the order of pile sinking and hole-guiding. As the name implies, the pre-guiding hole method is to use a long spiral drill or a rotary drilling rig to drill a hole before sinking the pipe pile. The diameter of the hole is 50mm~100mm smaller than the outer diameter of the pipe pile, and the depth of the hole is generally not more than 2 / 3 of the pile length. After the hole is completed, the pipe pile is sunk; the mid-excavation hole-guiding method is to use a short spiral device equipped with a rotary drilling power head to drill and extract soil in the pile hole. Pile sinking and hole-guiding can be carried out simultaneously or separately. Compared with the pre-guiding hole method, the mid-excavation hole-guiding method drills from the inner cavity of the pipe pile, using the pipe pile body as a protective wall. There is no need to use mud and other anti-collapse hole protective wall measures. Pile sinking and hole-guiding can be carried out simultaneously, and the verticality of the hole is guaranteed, effectively avoiding problems such as crooked piles and broken piles caused by the inclination of the hole wall.
[0005] When using the middle-dig hole method, the inner diameter of the pile hole is limited, and the drill must be prevented from getting stuck during drilling and lifting. The drill rod diameter is generally only 0.5~0.75 times the outer diameter of the pile. Even if the advance drilling method is used to extract soil, the volume of soil that the drill rod can extract only accounts for 0.25~0.56 times the volume of soil squeezed by the pile. In comparison, the soil extraction rate of the long spiral or rotary excavation pre-dig hole is 0.7~0.85. It can be seen that in the absence of effective measures to increase the amount of soil extracted, the middle-dig hole will affect its effectiveness in reducing the soil squeezing effect of the pile due to its low soil extraction rate. Utility Model Content
[0006] The purpose of the present application is to provide a steel pile tip that reduces the soil squeezing effect of a pipe pile, so as to solve the defects of a low soil extraction rate in the prior art hole digging method and a high soil extraction effect in the process of pipe pile sinking.
[0007] In order to achieve the above objectives, this application is implemented by adopting the following technical solutions:
[0008] A steel pile tip for reducing the soil squeezing effect of a pipe pile comprises an outer vertical ring plate, an inner conical ring plate and a stiffening plate; the outer vertical ring plate is fixed to the bottom of the pipe pile end plate, the inner conical ring plate is placed in the cavity of the outer vertical ring plate, one end of the inner conical ring plate is fixedly connected to the bottom of the pipe pile end plate, and the other end is fixedly connected to the inner wall of the outer vertical ring plate, and the stiffening plate is fixed in an installation area formed between the outer vertical ring plate and the inner conical ring plate.
[0009] According to a further solution of the present application, there are a plurality of stiffening plates, and the plurality of stiffening plates are fixed radially at equal angles in a mounting area formed between the outer vertical ring plate and the inner conical ring plate.
[0010] In a further solution, the outer diameter of the outer vertical ring plate is smaller than the outer diameter of the pipe pile end plate, and the difference between the outer diameter and the outer vertical ring plate is not less than the thickness of the outer vertical ring plate.
[0011] According to a further solution of the present application, the outer vertical ring plate and the pipe pile end plate are connected by a second fillet weld, and the weld leg size of the second fillet weld is one times the thickness of the outer vertical ring plate.
[0012] According to a further solution of the present application, the inner radius of the top of the inner conical ring plate is larger than the inner radius of the pipe pile end plate, and the difference between the two is substantially the thickness of the inner conical ring plate.
[0013] According to a further solution of the present application, the longitudinal height of the inner conical ring plate is smaller than the height of the outer vertical ring plate, and one end of the inner conical ring plate is connected to the pipe pile end plate by a third fillet weld, and the weld leg size of the third fillet weld is one times the thickness of the inner conical ring plate; the other end of the inner conical ring plate is connected to the outer vertical ring plate by a first fillet weld, and the weld leg size of the first fillet weld is one times the thickness of the inner conical ring plate.
[0014] According to a further solution of the present application, the stiffening plate and the outer vertical ring plate are welded together via a fourth fillet weld, and the size of the weld leg of the fourth fillet weld is one times the thickness of the stiffening plate.
[0015] According to a further solution of the present application, the angle between the surface of the inner conical ring plate and the horizontal plane is between 45° and 80°. The angle of the inner conical ring plate can be determined according to the soil and rock mechanics properties of the site. For sites with dense sand, silt and hard plastic clay, the inclination angle is between 60° and 80°. For other medium and soft soil sites, the inclination angle is between 45° and 60°.
[0016] The beneficial effects of this application are:
[0017] Compared with the traditional open pile tip, the pile tip in this application adopts the method of externally placing the outer vertical ring plate close to the end plate of the pipe pile, thereby increasing the soil cross-sectional area of the pile tip ring plate as much as possible. In actual tests, the soil cross-sectional rate is increased from 0.74 to 0.96. The inner inclined cone plate is fixed inside the outer vertical ring plate, and the soil intercepted by the outer vertical ring plate is smoothly introduced into the inner cavity of the pipe pile through the inner inclined cone plate, reducing the pile-crowding effect of the soil at the pile end. In the application of the middle excavation and hole method, the soil extraction rate of the middle excavation and hole method is increased from 32% to 90%, which greatly increases the soil extraction amount and can effectively reduce the soil extraction effect during the pipe pile sinking process.
[0018] The thickness of each fillet weld between the vertical ring plate, the inner conical ring plate, the stiffening plate and the pipe pile end plate is set to ensure the connection strength of the structure to the greatest extent and ensure the strength of use. BRIEF DESCRIPTION OF THE DRAWINGS
[0019] Figure 1 This is a schematic diagram of the middle digging and hole drawing method;
[0020] Figure 2 This is the cross-sectional view of the hole drilled by the middle-dig hole method;
[0021] Figure 3 This is a diagram of the pile tip structure in the embodiment of this application.
[0022] in:
[0023] 1. Outer vertical ring plate; 2. Inner conical ring plate; 3. Stiffening plate; 4. Pipe pile end plate; 5. First fillet weld; 6. Second fillet weld; 7. Third fillet weld; 8. Fourth fillet weld. DETAILED DESCRIPTION
[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present application and its application or use.
[0025] like Figure 1 and 2As shown in the geotechnical engineering survey report of a power plant, there is nearly 30m thick old clay distributed within a depth of 40m below the surface, which is in a state of hard plastic to hard, and has a moisture content of only 27%. Due to other environmental factors, the foundation treatment of this project adopts a low-noise, vibration-free static pressure method prestressed concrete pipe pile scheme, and the pile type is UHC700(110)AB. After investigation and research, it was found that the prefabricated pile scheme under similar sites in the area is prone to pile floating. Therefore, it was decided to adopt the static pressure pile sinking scheme of the middle excavation and digging hole, in the form of advanced soil drilling and soil discharge, to reduce the soil squeezing effect and form a dissipation channel for excess pore water pressure.
[0026] For pipe piles with a diameter of 700mm, the center-dig hole method can only be equipped with a short spiral drill rod with a diameter of 400mm, and its direct soil extraction rate is only 32%, which means that 68% of the remaining soil at the pile end will still be affected by the direct soil squeezing effect during the pile sinking process. Therefore, measures need to be taken to increase the soil extraction rate of the center-dig hole method. Embodiment 1
[0027] Observation attachment Figure 3 The present embodiment discloses a steel pile tip for reducing the soil squeezing effect of a pipe pile, which includes three major components, namely an outer vertical ring plate 1, an inner conical ring plate 2 and a stiffening plate 3. The outer vertical ring plate 1 is fixed to the bottom of the pipe pile end plate 4, and the inner conical ring plate 2 is placed in the cavity of the outer vertical ring plate 1. One end of the inner conical ring plate 2 is fixedly connected to the bottom of the pipe pile end plate 4, and the other end is fixedly connected to the inner wall of the outer vertical ring plate 1. The stiffening plate 3 is fixed in the installation area formed between the outer vertical ring plate 1 and the inner conical ring plate 2. Finally, the three constitute a frustum-shaped inner cavity space that is "small on the top and large on the bottom".
[0028] like Figure 3 As shown, the outer vertical ring plate 1 is arranged on the outer side of the bottom of the pipe pile end plate 4, the thickness t1 of the outer vertical ring plate 1 is 12 mm, and the outer radius of the outer vertical ring plate 1 is smaller than the outer radius of the pipe pile end plate 4, so as to reserve a welding space between the outer vertical ring plate 1 and the pipe pile end plate 4, and the difference h1 between the two is designed to be 15 mm;
[0029] like Figure 3 As shown, the outer vertical ring plate 1 and the pipe pile end plate 4 are connected by a second fillet weld 6, and the weld leg size of the second fillet weld 6 is one times the thickness t1 of the outer vertical ring plate 1;
[0030] like Figure 3 As shown, the inner conical ring plate 2 is arranged on the inner side of the bottom of the pipe pile end plate 4, the thickness t2 of the inner oblique cone plate 2 is 12mm, and the inner radius of the top is larger than the inner radius of the pipe pile end plate 4, so as to reserve a welding space between the inner oblique cone plate 22 and the pipe pile end plate 4, and the difference h2 between the two is 15mm;
[0031] like Figure 3As shown, the inner conical ring plate 2 and the pipe pile end plate 4 are connected by a third fillet weld 7, and the weld leg size of the third fillet weld is one time the thickness t2 of the inner conical ring plate 2;
[0032] like Figure 3 As shown, stiffening plates 3 are evenly arranged between the outer vertical ring plate 1 and the inner conical ring plate 2 along the annular direction, the plate thickness t3 of the stiffening plates 3 is 10 mm, and the spacing angle between adjacent stiffening plates 3 is 45°; the stiffening plates 3 and the outer vertical ring plate 1 are connected by a fourth fillet weld 8, and the weld leg size of the fourth fillet weld 8 is one times the plate thickness t3 of the stiffening plate; the stiffening plates 3 and the inner conical ring plate 2 are installed tightly, and no weld connection is provided;
[0033] The dimension H of the outer vertical ring plate 1 in the vertical direction exceeds that of the inner conical ring plate 2. The intersection of the two is connected by a first fillet weld 5. The weld leg dimension of the first fillet weld 5 is one time the thickness t2 of the inner conical ring plate 2. Embodiment 2
[0034] In other embodiments, the inclination angle of the plate surface of the outer vertical ring plate is designed, and the angle of the inner conical ring plate 2 can be specifically designed according to the soil and rock mechanical properties of the site. For sites with dense sand, silt and hard plastic clay, the inclination angle is between 60° and 80°, and for other medium and soft soil sites, the inclination angle is between 45° and 60°;
[0035] In this embodiment, the inclined angle θ between the plate surface of the inner inclined cone plate 2 and the horizontal plane is 75°, so as to adapt to the hard plastic to hard old clay with high strength and low water content, and achieve the purpose of increasing the cross-sectional area of the pile tip.
[0036] Specific use:
[0037] The steel pile tip in Example 1 or Example 2 is installed on the surface of the pipe pile end plate 4. When the pipe pile is pressed down into the hole, the setting of the outer vertical ring plate 1 increases the cross-sectional area of the vertical ring plate 1 as much as possible, and the soil intercepted by the outer vertical ring plate 1 is smoothly introduced into the inner cavity of the pipe pile, reducing the squeezing effect of the soil at the pile end, greatly increasing the amount of soil taken, and then effectively reducing the soil taking effect during the pipe pile sinking process.
[0038] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application 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 application. In addition, the terms "first", "second", etc. are used only for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Thus, features defined as "first", "second", etc. may explicitly or implicitly include one or more of the features. In the description of the present application, unless otherwise specified, "multiple" means two or more.
[0039] In the description of this application, 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 the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood by specific circumstances.
Claims
1. A steel pile tip for reducing soil squeezing effect of a pipe pile, characterized in that: The invention comprises an outer vertical ring plate (1), an inner conical ring plate (2) and a stiffening plate (3); the outer vertical ring plate (1) is fixed to the bottom of a pipe pile end plate (4); the inner conical ring plate (2) is placed in a cavity of the outer vertical ring plate (1); one end of the inner conical ring plate (2) is fixedly connected to the bottom of the pipe pile end plate (4); the other end of the inner conical ring plate (2) is fixedly connected to the inner wall of the outer vertical ring plate (1); and the stiffening plate (3) is fixed in an installation area formed between the outer vertical ring plate (1) and the inner conical ring plate (2).
2. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 1, characterized in that: There are a plurality of stiffening plates (3), and the plurality of stiffening plates (3) are fixed at equal radial angles in a mounting area formed between the outer vertical ring plate (1) and the inner conical ring plate (2).
3. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 2, characterized in that: The outer diameter of the outer vertical ring plate (1) is smaller than the outer diameter of the pipe pile end plate (4), and the difference between the two is not less than the thickness of the outer vertical ring plate (1).
4. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 1, characterized in that: The outer vertical ring plate (1) and the pipe pile end plate (4) are connected by circumferential welding via a second fillet weld (6), and the weld leg size of the second fillet weld (6) is one times the thickness of the outer vertical ring plate (1).
5. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 1, characterized in that: The inner radius of the top of the inner conical ring plate (2) is larger than the inner radius of the pipe pile end plate (4), and the difference between the two is not small in the thickness of the inner conical ring plate (2).
6. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 1, characterized in that: The longitudinal height of the inner conical ring plate (2) is smaller than the height of the outer vertical ring plate (1); one end of the inner conical ring plate (2) is connected to the pipe pile end plate (4) by a third fillet weld (7); the weld leg size of the third fillet weld (7) is one times the thickness of the inner conical ring plate (2); the other end of the inner conical ring plate (2) is connected to the outer vertical ring plate (1) by a first fillet weld (5); the weld leg size of the first fillet weld (5) is one times the thickness of the inner conical ring plate (2).
7. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 1, characterized in that: The stiffening plate (3) and the outer vertical ring plate (1) are welded together via a fourth fillet weld (8), and the size of the weld leg of the fourth fillet weld (8) is one times the thickness of the stiffening plate (3).
8. The steel pile tip for reducing soil squeezing effect of pipe pile according to claim 1, characterized in that: The angle between the plate surface of the inner conical ring plate (2) and the horizontal plane is between 45° and 80°.