Variable cross-section core-sand filling drainage bamboo pile for soft foundation reinforcement

Abstract

The utility model discloses a variable cross-section core-filling sand drainage bamboo pile for soft foundation reinforcement, which comprises a first bamboo pile and a second bamboo pile, the second bamboo pile is filled with concrete, drainage sand is filled between the inner wall of the first bamboo pile and the outer wall of the second bamboo pile, the surface of the first bamboo pile is provided with drainage holes, and the outer wall of the second bamboo pile is provided with drainage holes. The length of the first bamboo pile is smaller than that of the second bamboo pile, the lower end of the first bamboo pile is fixedly arranged on the surface of the second bamboo pile through a variable cross-section sleeve, the variable cross-section sleeve is conical, and an opening in the upper end of the variable cross-section sleeve is larger than an opening in the lower end of the variable cross-section sleeve. The variable-cross-section core-sand filling drainage bamboo pile for reinforcing the soft foundation is of a variable-cross-section structure which is thick at the upper part and thin at the lower part, drainage and vertical bearing capacity can be both considered, soil penetrating resistance is reduced, and transverse shear resistance is improved.

Description

Technical Field

[0001] This utility model belongs to the field of foundation engineering, and in particular relates to a drainage bamboo pile. Background Technology

[0002] In soft soil foundation reinforcement projects, soft soils such as soft clay, silty soil, and high-moisture-content silty clay are prone to uneven settlement of buildings and slope slippage due to high pore water pressure, slow consolidation rate, and low bearing capacity. Drainage consolidation method has become the core technical approach for this type of foundation reinforcement. Bamboo piles, with their advantages of being renewable, low-cost, easy to construct, and in line with green infrastructure, combined with a core-filled sand drainage structure to form a core-filled sand drainage bamboo pile, have become a high-quality alternative to traditional plastic drainage boards and concrete drainage piles because they have the dual functions of foundation reinforcement and drainage consolidation. They are widely used in soft soil foundation projects such as rural infrastructure, riverbank protection, small building foundations, and low-fill roadbeds.

[0003] For example, the utility model patent with announcement number CN222685460U discloses a sleeve-type precast bamboo pile structure with core concrete and ring sand for the reinforcement of soft foundations. It has the dual functions of foundation reinforcement and drainage consolidation. The bamboo pile structure adopts a uniform cross-section design with a uniform pile diameter. The cross-sectional dimensions of the inner core concrete layer and the filling sand layer are also fixed. However, this bamboo pile structure has significant technical shortcomings in adapting to the engineering requirements of complex soft foundations, as follows: First, the stress is inconsistent with the gradient stress characteristics of the foundation. The uniform cross-section pile body cannot fully adapt to the stress requirements at different depths. The lateral earth pressure in the middle and lower sections is relatively small, which easily leads to redundant stiffness in the lower part. The middle and lower sections of the pile body are located in the shear influence zone of the foundation. First, the piles are subjected to the coupled effects of lateral earth pressure and vertical skin friction, resulting in deficiencies in shear bearing capacity and anti-sliding performance at the pile-soil interface. Second, the pile tip lacks drag reduction design, leading to high penetration resistance during driving and making the pile prone to splitting and deflection. Third, the pile has poor interlocking with the soil, relying solely on surface skin friction to bond with the surrounding soil. In engineering scenarios such as riverbank protection and road slopes subjected to continuous lateral earth pressure, the lateral anti-sliding capacity is weak, making it difficult to meet the stability requirements of slope reinforcement. Fourth, there is redundancy in material utilization. The uniform cross-section design does not accurately match the cross-sectional dimensions according to the stress requirements of each section, resulting in material redundancy in some areas, increasing project costs and failing to meet the principle of efficient material utilization in green infrastructure. Utility Model Content

[0004] The technical problem to be solved by this utility model is to overcome the deficiencies and defects mentioned in the background art above, and to provide a variable cross-section core-filled sand drainage bamboo pile for the reinforcement of soft foundations. This drainage bamboo pile can be adapted to the gradient stress characteristics of the foundation and realize the synergistic optimization of structural bearing capacity and engineering economy.

[0005] To solve the above-mentioned technical problems, the technical solution proposed by this utility model is as follows:

[0006] A variable cross-section core-filled sand drainage bamboo pile for reinforcing weak foundations includes a first bamboo pile and a second bamboo pile. The first bamboo pile is sleeved on the outside of the second bamboo pile, and the second bamboo pile is filled with concrete. Drainage sand is filled between the inner wall of the first bamboo pile and the outer wall of the second bamboo pile. Drainage holes are opened on the surface of the first bamboo pile. The length of the first bamboo pile is shorter than that of the second bamboo pile. The first bamboo pile is located in the upper middle part of the second bamboo pile. The lower end of the first bamboo pile is fixed to the surface of the second bamboo pile by a variable cross-section sleeve. The variable cross-section sleeve is conical, with the upper opening being larger than the lower opening. The upper dimension of the variable cross-section sleeve matches the lower dimension of the first bamboo pile, and the lower dimension of the variable cross-section sleeve matches the outer diameter of the second bamboo pile.

[0007] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for reinforcing weak foundations, preferably, the inner cavities of both the first and second bamboo piles are hollow structures with all internal bamboo nodes removed. Removing all internal bamboo nodes from both the first and second bamboo piles ensures that the inner cavities possess good flatness and cleanliness.

[0008] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for soft soil foundation reinforcement, preferably, the space between the inner wall of the variable cross-section sleeve and the outer wall of the second bamboo pile is filled with concrete. This arrangement can further improve the connection performance at the variable cross-section sleeve joint and enhance the overall structural integrity.

[0009] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for reinforcing weak foundations, preferably, both the inner and outer surfaces of the first and second bamboo piles are coated with a layer of anti-corrosion material. The application of this anti-corrosion material layer helps improve the anti-corrosion performance of the bamboo.

[0010] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for soft foundation reinforcement, preferably, the outer surface of the first bamboo pile is covered with non-woven geotextile by binding straps. The non-woven geotextile can filter and prevent fine sand from entering the soft foundation.

[0011] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for reinforcing weak foundations, preferably, the bottom of the second bamboo pile is pointed. The pointed shape is more conducive to driving the aforementioned variable cross-section core-filled sand drainage bamboo piles into the weak foundation.

[0012] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for soft foundation reinforcement, preferably, the upper and lower ends of the variable cross-section sleeve are respectively provided with an upper fixed diameter section and a lower fixed diameter section, and the area between the upper and lower fixed diameter sections is a variable cross-section section. The use of upper and lower fixed diameter sections facilitates the connection between the variable cross-section sleeve and the first and second bamboo piles.

[0013] In the aforementioned variable cross-section core-filled sand drainage bamboo piles used for soft soil foundation reinforcement, preferably, the lower end outer wall of the first bamboo pile is threaded, and the inner cavity of the upper fixed diameter section is threaded, with the lower end of the first bamboo pile and the upper fixed diameter section connected by threads; the middle outer wall of the second bamboo pile is threaded, and the inner cavity of the lower fixed diameter section is threaded, with the middle part of the second bamboo pile and the lower fixed diameter section connected by threads. Both the first and second bamboo piles are threaded to the variable cross-section sleeve, making assembly more convenient.

[0014] In the above-mentioned variable cross-section core-filled sand drainage bamboo piles used for soft foundation reinforcement, preferably, the outer diameter of the second bamboo pile is smaller than the inner diameter of the first bamboo pile; the diameter of the drainage holes on the surface of the first bamboo pile is 8-10mm, and 10-15 drainage holes are evenly opened on each section.

[0015] This utility model relates to a variable cross-section core-filled sand drainage bamboo pile for soft soil foundation reinforcement. It features a simple structure, easy assembly, and applicability to various soft soil foundation reinforcement methods. During construction, the first and second bamboo piles are connected using a variable cross-section sleeve. Concrete grout is then poured into the second bamboo pile and the variable cross-section sleeve. Drainage sand is placed in the annular cavity between the inner wall of the first bamboo pile and the outer wall of the second bamboo pile. The device is then driven into the foundation, and a static pressure pile driver is used to slowly press the bamboo pile into the soil. The smaller cross-section at the bottom reduces the resistance to soil penetration, while the larger cross-section at the top ensures stable stress distribution. The pile driving process is continuous and uniform. Finally, the pile top is treated to prevent debris from entering the drainage channel, completing the single pile construction.

[0016] Compared with the prior art, the advantages of this utility model are:

[0017] This utility model relates to a variable cross-section core-filled sand drainage bamboo pile for reinforcing soft foundations. It addresses the contradiction between structural stress and foundation gradient stress. The lower section uses a variable cross-section sleeve to reduce the overall cross-sectional area of ​​the bamboo pile, which adapts to changes in lateral earth pressure while maintaining sufficient rigidity. The conical structure of the variable cross-section sleeve increases the contact area with shallow soil, disperses the lateral earth pressure in the lower section, and improves the shear resistance and anti-sliding capacity of the pile.

[0018] This utility model relates to a variable cross-section core-filled sand drainage bamboo pile for reinforcing soft foundations. The second bamboo pile adopts a small cross-section and a pointed bottom design, which significantly reduces the resistance of the pile tip entering the soil, reduces the risk of pile splitting and deflection during the pile driving process, and reduces the disturbance of the surrounding soft soil during construction.

[0019] This utility model discloses a variable cross-section core-filled sand drainage bamboo pile for the reinforcement of soft foundations. The conical structure of the variable cross-section sleeve further increases the frictional contact area between the pile body and the shallow soil, thereby improving the frictional resistance between the pile body and the soil. The double-layer bamboo pile is solidified by concrete pouring to form an integrated rigid pile body. The non-woven geotextile wrapped around the first bamboo pile increases the interlocking between the pile and the soil, significantly improving the lateral shear and sliding resistance of the pile body. It can meet the engineering reinforcement needs of riverbank protection, road slopes and other projects subjected to continuous lateral earth pressure.

[0020] This utility model relates to a variable cross-section core-filled sand drainage bamboo pile for reinforcing soft foundations. The variable cross-section structure is precisely designed according to the stress requirements of each section of the pile body. The large upper cross-section ensures bearing capacity, while the small lower cross-section reduces material consumption and reduces the area of ​​stress redundancy, thus achieving efficient use of materials.

[0021] This utility model relates to a variable cross-section core-filled sand drainage bamboo pile for reinforcing soft foundations. The use of renewable bamboo and recycled concrete aligns with the concept of green infrastructure, improves the economic efficiency of the project, and can effectively meet the drainage, consolidation and reinforcement needs of various soft foundations such as soft soil, silty soil, and high-moisture silty clay. Attached Figure Description

[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0023] Figure 1 This is a schematic diagram of the variable cross-section core-filled sand drainage bamboo pile of this utility model for reinforcing soft foundations.

[0024] Figure 2 This is a structural schematic diagram of the variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement of this utility model, without concrete, drainage sand and non-woven geotextile.

[0025] Figure 3 This is a schematic diagram of the variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement of this utility model at the variable cross-section sleeve connection (threads have been omitted).

[0026] Legend

[0027] 1. Concrete; 2. Second bamboo pile; 3. First bamboo pile; 4. Drainage sand; 5. Drainage hole; 6. Variable cross-section sleeve; 61. Upper fixed diameter section; 62. Variable cross-section section; 63. Lower fixed diameter section; 7. Binding strap; 8. Non-woven geotextile. Detailed Implementation

[0028] To facilitate understanding of this utility model, it will be described more comprehensively and in detail below with reference to the accompanying drawings and preferred embodiments. However, the scope of protection of this utility model is not limited to the following specific embodiments.

[0029] It should be noted that when a component is described as being "fixed to, attached to, connected to or connected to" another component, it can be directly fixed to, attached to, connected to or connected to the other component, or it can be indirectly fixed to, attached to, connected to or connected to the other component through other intermediate connectors.

[0030] Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by those skilled in the art. The technical terms used herein are for the purpose of describing particular embodiments only and are not intended to limit the scope of protection of this invention.

[0031] Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this invention can be purchased from the market or prepared by existing methods.

[0032] Example:

[0033] like Figures 1-3 As shown, the variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement in this embodiment includes a first bamboo pile 3 and a second bamboo pile 2. The first bamboo pile 3 is sleeved on the outside of the second bamboo pile 2. The second bamboo pile 2 is filled with concrete 1. Drainage sand 4 is filled between the inner wall of the first bamboo pile 3 and the outer wall of the second bamboo pile 2. Drainage holes 5 are opened on the surface of the first bamboo pile 3. The length of the first bamboo pile 3 is shorter than that of the second bamboo pile 2. The first bamboo pile 3 is located in the upper middle part of the second bamboo pile 2. The lower end of the first bamboo pile 3 is fixed to the surface of the second bamboo pile 2 by a variable cross-section sleeve 6. The variable cross-section sleeve 6 is conical, with the upper opening being larger than the lower opening. The upper dimension of the variable cross-section sleeve 6 matches the lower dimension of the first bamboo pile 3, and the lower dimension of the variable cross-section sleeve 6 matches the outer diameter of the second bamboo pile 2.

[0034] In this embodiment, the inner cavities of the first bamboo stake 3 and the second bamboo stake 2 are both hollow structures with all internal bamboo nodes removed.

[0035] In this embodiment, concrete 1 is filled between the inner wall of the variable cross-section sleeve 6 and the outer wall of the second bamboo pile 2.

[0036] In this embodiment, both the inner and outer surfaces of the first bamboo stake 3 and the second bamboo stake 2 are coated with an anti-corrosion material layer. The choice of anti-corrosion material is not limited; for example, tung oil can be used.

[0037] In this embodiment, the outer surface of the first bamboo pile 3 is covered with non-woven geotextile 8 by binding straps 7, and the non-woven geotextile 8 covers the drainage hole 5 at the top of the first bamboo pile 3 to the drainage hole 5 at the bottom of the first bamboo pile 3.

[0038] In this embodiment, the bottom of the second bamboo pile 2 is pointed, and concrete 1 is simultaneously placed at the pointed end of the second bamboo pile 2 to facilitate driving it into the soft soil foundation.

[0039] In this embodiment, the upper and lower ends of the variable cross-section sleeve 6 are respectively provided with an upper fixed diameter section 61 and a lower fixed diameter section 63, and the variable cross-section section 62 is located between the upper fixed diameter section 61 and the lower fixed diameter section 63. The lower end of the first bamboo stake 3 is threaded on its outer wall, and the inner cavity of the upper fixed diameter section 61 is threaded. The lower end of the first bamboo stake 3 and the upper fixed diameter section 61 are connected by threads. The middle outer wall of the second bamboo stake 2 is threaded, and the inner cavity of the lower fixed diameter section 63 is threaded. The middle part of the second bamboo stake 2 and the lower fixed diameter section 63 are connected by threads.

[0040] In this embodiment, the lengths of the second bamboo stake 2 and the first bamboo stake 3 can be 6m and 3m respectively. The outer diameter of the second bamboo stake 2 can be 15cm, and the outer diameter of the first bamboo stake 3 can be 25cm. The inner diameter of the variable cross-section sleeve 6 varies from 25cm to 15cm. The diameter of the drainage holes 5 can be 1cm, and they are evenly distributed. The concrete 1 can be precast recycled concrete. The drainage sand 4 used for drainage can be medium-coarse sand. The variable cross-section sleeve 6 can be made of rubber.

[0041] The variable cross-section core-filled sand drainage bamboo pile used in this embodiment for soft soil foundation reinforcement has a "thicker at the top and thinner at the bottom" structure, which is a variable cross-section structure that can balance drainage and vertical bearing capacity, reduce soil penetration resistance, and improve lateral shear resistance. After being driven into the soft soil foundation through drainage holes 5 and drainage sand 4, water in the foundation enters the first bamboo pile 3 through the drainage holes 5, and then is discharged from the top of the first bamboo pile 3 through the capillary effect of the drainage sand 4 particles. The inner cavity of the second bamboo pile 2 is filled with concrete 1, which can effectively improve the pile bearing capacity. The variable cross-section sleeve 6 is filled with concrete 1 to achieve the fixed connection between the first bamboo pile 3 and the second bamboo pile 2, which facilitates their synchronous driving.

[0042] The above description is merely a preferred embodiment of this utility model and is not intended to limit the scope of this utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A variable cross-section core-filled sand drainage bamboo pile for reinforcing weak foundations, comprising a first bamboo pile (3) and a second bamboo pile (2), wherein the first bamboo pile (3) is sleeved on the outside of the second bamboo pile (2), the second bamboo pile (2) is filled with concrete (1), and drainage sand (4) is filled between the inner wall of the first bamboo pile (3) and the outer wall of the second bamboo pile (2), and drainage holes (5) are provided on the surface of the first bamboo pile (3), characterized in that, The first bamboo stake (3) is shorter than the second bamboo stake (2). The first bamboo stake (3) is located in the upper middle part of the second bamboo stake (2). The lower end of the first bamboo stake (3) is fixed to the surface of the second bamboo stake (2) by a variable cross-section sleeve (6). The variable cross-section sleeve (6) is conical, with the upper opening larger than the lower opening. The upper dimension of the variable cross-section sleeve (6) matches the lower dimension of the first bamboo stake (3). The lower dimension of the variable cross-section sleeve (6) matches the outer diameter of the second bamboo stake (2).

2. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 1, characterized in that, The inner cavities of the first bamboo stake (3) and the second bamboo stake (2) are both hollow structures with all internal bamboo nodes removed.

3. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 1, characterized in that, The space between the inner wall of the variable cross-section sleeve (6) and the outer wall of the second bamboo pile (2) is filled with concrete (1).

4. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 1, characterized in that, The inner and outer surfaces of the first bamboo stake (3) and the second bamboo stake (2) are coated with a layer of anti-corrosion material.

5. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 1, characterized in that, The outer surface of the first bamboo stake (3) is covered with non-woven geotextile (8) by binding straps (7).

6. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 1, characterized in that, The bottom of the second bamboo stake (2) is pointed.

7. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 1, characterized in that, The upper end and lower end of the variable cross-section sleeve (6) are respectively provided with an upper fixed diameter section (61) and a lower fixed diameter section (63), and the variable cross-section section (62) is between the upper fixed diameter section (61) and the lower fixed diameter section (63).

8. The variable cross-section core-filled sand drainage bamboo pile for soft foundation reinforcement according to claim 7, characterized in that, The lower end of the first bamboo stake (3) is threaded on its outer wall, and the inner cavity of the upper fixed diameter section (61) is threaded. The lower end of the first bamboo stake (3) and the upper fixed diameter section (61) are connected by threads. The middle part of the second bamboo stake (2) is threaded on its outer wall, and the inner cavity of the lower fixed diameter section (63) is threaded. The middle part of the second bamboo stake (2) and the lower fixed diameter section (63) are connected by threads.

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