Core sand drainage prefabricated bamboo pile for soft foundation reinforcement

Abstract

The utility model discloses a core sand drainage prefabricated bamboo pile for soft foundation reinforcement, which comprises a bamboo pile with a hollow inner cavity, drainage sand is filled in the inner cavity of the bamboo pile, the outer surface of the bamboo pile is provided with a plurality of drainage holes for drainage, the density of the drainage holes is increased from top to bottom, and the drainage sand is filled in the inner cavity of the bamboo pile. And the outer surface of the bamboo pile is coated with a filter layer. According to the core sand drainage prefabricated bamboo pile, the drainage advantage of the sand well technology is reserved, meanwhile, the defects of complex construction, high cost and insufficient durability of the core sand drainage prefabricated bamboo pile are overcome, and an efficient, economical and sustainable solution is provided for soft foundation reinforcement.

Description

Technical Field

[0001] This utility model belongs to the field of foundation engineering, and particularly relates to a structure for reinforcing weak foundations. Background Technology

[0002] In the field of engineering construction, soft foundations are generally composed of soil layers with high compressibility and low permeability, such as silt, peat, organic soil, and loose fill. These foundations naturally have high water content, large void ratio, and low shear strength, often resulting in insufficient bearing capacity (generally below 80 kPa) and long-term consolidation settlement. Without effective reinforcement, buildings are highly likely to experience uneven settlement, structural cracking, or even overturning, especially in areas with complex geological conditions such as coastal areas and alluvial plains.

[0003] Sand well technology, as a traditional method of foundation drainage and reinforcement, is widely used in the treatment of weak foundations. However, sand well technology also has problems such as complex construction, requiring a large amount of sand and mechanical equipment, and a long construction period. In terms of cost, the cost of sand well treatment is approximately 100-130 yuan / m³. 2 In addition to the costs of sand transportation and construction, the overall cost is relatively high; in terms of durability, sand wells may experience a decline in drainage performance due to sand loss or siltation during long-term use. Therefore, an alternative solution for sand wells is needed. 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 precast bamboo pile with core sand drainage that is easy to construct, low in cost, durable, and has high drainage efficiency for the reinforcement of soft foundations.

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

[0006] A precast bamboo pile with core sand drainage for reinforcing weak foundations includes a bamboo pile with a hollow inner cavity, the inner cavity of which is filled with drainage sand (which can be pure fine sand with impurities removed), the outer surface of the bamboo pile has multiple drainage holes for drainage, and the density of the drainage holes increases from top to bottom, and the outer surface of the bamboo pile is covered with a filter layer.

[0007] In the aforementioned precast bamboo pile with core sand drainage, preferably, the inner cavity of the bamboo pile is a hollow structure that retains only the bottom inner bamboo node while removing the other inner bamboo nodes. The inner cavity of the bamboo pile is divided into an upper chamber and a lower chamber by the bottom inner bamboo node. The upper chamber is filled with drainage sand, and the drainage holes and filter layer are located in the upper chamber. The lower chamber is filled with concrete. Retaining the bottom inner bamboo node and removing the other bamboo nodes makes the upper cavity of the bamboo pile smooth, while the bottom inner bamboo node provides support and sealing. The length of the lower chamber can be the length of one bamboo node (i.e., the length between adjacent bamboo nodes). Filling the lower chamber with concrete not only enhances the stability and durability of the pile but also better transfers the load of the superstructure to the deeper foundation, further reinforcing weak foundations. The concrete can be recycled aggregate concrete.

[0008] In the aforementioned precast bamboo piles with core sand drainage, preferably, the length of the lower chamber is shorter than that of the upper chamber. The length of the upper chamber can be the length of multiple bamboo sections, while the length of the lower chamber can be the length of one bamboo section. The upper chamber is longer and mainly used for drainage, while the lower chamber is mainly used for pile driving, so its length can be shortened to maximize the length of the drainage section and improve drainage efficiency.

[0009] In the aforementioned precast bamboo piles with core sand drainage, preferably, the bottom of the bamboo pile is set in a pointed shape, and the concrete filling the lower cavity is also in a pointed shape. Setting a pointed bottom of the bamboo pile helps to drive the bamboo pile into a soft foundation, and the concrete in the lower cavity also matches the shape of the lower cavity.

[0010] In the aforementioned precast bamboo piles with core sand drainage, preferably, the filter layer is a non-woven geotextile layer, which is wrapped around the outer surface of the bamboo pile by binding straps. The non-woven geotextile can filter and prevent fine sand from entering the soft foundation.

[0011] In the aforementioned precast bamboo piles with core sand drainage, preferably, the inner cavity of the bamboo pile is provided with a filter cloth to prevent the drainage sand from leaking outward through the drainage holes. Since drainage sand may leak outward through the drainage holes, this invention adds a filter cloth to the inner cavity of the bamboo pile to prevent leakage. This filter cloth can be made of ultra-thin non-woven geotextile or other materials, as long as it can perform a filtering function.

[0012] In the aforementioned precast bamboo piles with core sand drainage, preferably, the drainage hole is a horizontally arranged conical hole, with a larger inlet on the outer side of the bamboo pile and a smaller outlet on the inner side. This structural form of the drainage hole allows for the large inlet, facilitating the infiltration of water from the soft foundation into the bamboo pile, while the small outlet prevents the drainage sand from leaking outwards.

[0013] In the aforementioned precast bamboo piles with core sand drainage, preferably, both the inner and outer surfaces of the bamboo pile are coated with a layer of anti-corrosion material. The addition of this anti-corrosion material layer helps improve the anti-corrosion performance of the bamboo.

[0014] In the above-mentioned precast bamboo piles with core sand drainage, preferably, the diameter of the drainage holes can be 1-2cm, and different densities can be set according to different heights to form a gradient drainage effect. The number of drainage holes on each section can be 10-25.

[0015] This utility model relates to a precast bamboo pile with core sand drainage system. Utilizing bamboo as a natural material and combining it with the precast construction concept, it provides a structural reinforcement solution for weak foundations with excellent drainage and reinforcement effects. During precasting, holes are first drilled into the surface of the raw bamboo. Then, a layer of non-woven geotextile is wrapped around the bamboo tube (i.e., the bamboo pile) and drainage sand (fine sand) is filled inside. Finally, the bottom of the bamboo tube is filled with renewable aggregate concrete. After being driven into the weak foundation, the fine sand inside the bamboo tube achieves gradient drainage through capillary action. The consolidated renewable aggregate concrete and bamboo pile allow the pile to better transfer the load from the superstructure to the deeper layers of the foundation, thereby improving the bearing capacity of the weak foundation. The following describes the precast bamboo pile structure with core sand drainage system through detailed precasting and driving methods, which include the following steps:

[0016] Bamboo Selection: Raw bamboo should meet the required diameter, such as giant dragon bamboo. Ideally, the raw bamboo should be at least three years old and free from severe cracks, insect infestation, mold, or drying defects. For projects with relatively low load-bearing requirements, the diameter of the bamboo tube should be greater than 200mm; for projects with heavier loads, the diameter should be greater than 250mm. The bamboo length can range from 1.0 to 6.0m, and the wall thickness should be greater than 5mm.

[0017] Hollowing out the original bamboo nodes (retaining the inner nodes at the bottom of the large-diameter bamboo tube): Select the original bamboo to be processed, remove the bamboo nodes inside (retaining the inner nodes at the bottom of the large-diameter bamboo tube), and thoroughly clean the inner cavity of the original bamboo to ensure that the inner cavity has good flatness and cleanliness, laying the foundation for subsequent processes.

[0018] Raw bamboo drying: A drying process is performed on the raw bamboo to precisely control its moisture content to the predetermined standard. This step plays a crucial role in ensuring the stable performance of the bamboo in subsequent engineering projects. After drying, the bamboo is cut and processed according to design requirements to ensure its length and diameter meet the dimensions of the pile.

[0019] Drilling holes in the bamboo tube: Drilling holes on the surface of the raw bamboo to create drainage holes. To ensure drainage efficiency and minimize the impact on the bamboo's strength, the hole diameter can be selected to be around 1-2 cm, without excessively weakening the bamboo stake's strength. In terms of quantity, different densities are set according to different heights to create a gradient drainage effect, with 10-25 holes drilled in each section of the bamboo.

[0020] Bamboo tube surface coating with anti-corrosion: After completing the above steps, apply an impregnating anti-corrosion material evenly to the inner and outer surfaces of the raw bamboo. The anti-corrosion material can be any one of tung oil, raw lacquer, ACQ (alkaline copper quaternary ammonium salt), CCA (copper chromium arsenic compound), asphalt, or coal tar. It needs to be applied 2 to 3 times to ensure that the inner and outer surfaces of the raw bamboo are fully covered and impregnated, thereby improving the anti-corrosion performance of the raw bamboo.

[0021] Binding the non-woven geotextile: Select a suitable non-woven geotextile and tightly wrap it around the outer circumference of the large-diameter bamboo tube with binding tape. The binding tape can be any of the following: bamboo rattan, bamboo bundles, bamboo fiber sheets, metal strips, or fiber strips. When wrapping, ensure the non-woven geotextile is flat, wrinkle-free, and securely bound to the original bamboo. The function of the non-woven geotextile is to filter and prevent fine sand from entering the soft soil during subsequent drainage.

[0022] Grouting and Sand Injection: Prepare concrete and pure fine sand. During bottom grouting, closely monitor changes in grouting pressure and flow rate to ensure uniformity and compactness. Once the grouting volume reaches the design requirements or the grouting pressure stabilizes at a certain value for a period of time, close the grouting valve, clean and maintain the grouting equipment, and prepare for the next grouting. For sand injection, inject fine sand into the upper end. During injection, use a thin tool (such as a bamboo strip) to gently tamp the fine sand, making it fill more densely and forming a better capillary structure inside the bamboo tube. Recycled aggregate concrete can be used to reduce the consumption of natural resources and lower costs. During grouting, ensure the compactness of the recycled aggregate concrete to avoid quality problems such as honeycomb and pitting.

[0023] Driving Raw Bamboo: Raw bamboo is driven into the soft foundation using a static pressure method. A soft pad is placed on top of the bamboo during this process to prevent cracking at the top. Specifically, suitable static pressure equipment is used to precisely drive the treated bamboo into the soft foundation according to the pre-designed pile positions. A soft pad is placed at the top of the bamboo pile to prevent damage to the top during driving. The driving force and speed are strictly controlled to ensure the bamboo sinks vertically and prevent tilting or displacement. The driving process is closely monitored. If abnormal resistance or other problems are encountered, construction is immediately stopped, the cause analyzed, and effective solutions implemented. The driven bamboo is inspected to confirm that its depth and position meet design requirements. Any deviations are adjusted promptly. Professional measuring tools can be used to measure the top elevation of the bamboo to ensure consistent pile height, laying a good foundation for subsequent grouting.

[0024] Of the above steps, the last step is on-site construction, while the preceding steps can all be prefabricated in the factory.

[0025] This utility model relates to precast bamboo piles for core sand drainage, utilizing bamboo to reinforce weak foundations. Bamboo offers unique advantages in this area: bamboo raw materials are readily available and inexpensive in many regions, reducing project costs. Bamboo is lighter than traditional piles, facilitating transportation and construction, reducing the frequency of using large machinery and lowering energy consumption. The use of bamboo effectively conserves steel, a non-renewable resource. Steel production often involves high energy consumption and pollution, while bamboo, as a renewable resource, alleviates environmental pressure to some extent, saving resources, protecting the environment, and reducing pollution throughout the building's lifecycle. Furthermore, drainage sand and concrete are both low-cost materials. Compared to traditional sand wells, this combination offers advantages such as simple construction, short construction period, and low cost. Moreover, the coating of the inner and outer surfaces of the bamboo piles with anti-corrosion materials and the binding of non-woven geotextile to the outer surface effectively improves the bamboo piles' corrosion resistance and erosion resistance, extending their service life and ensuring long-term stable operation in weak foundations. Compared to traditional sand wells, it has advantages such as better durability.

[0026] In this invention, drainage sand is used to facilitate the upward drainage of water that seeps into the inner cavity of the bamboo pile through the drainage holes. The drainage sand is pure, fine sand with impurities removed to ensure unobstructed drainage channels, allowing water in soft soil foundations to drain quickly and efficiently. The drainage holes are through-holes penetrating the outer wall of the bamboo pile, with their density increasing from top to bottom, enabling more efficient drainage and directional, rapid removal of soil moisture. This is particularly suitable for soft soil foundations where the water content increases with depth, resulting in superior drainage performance. The filter layer prevents the drainage sand from leaking out through the drainage holes and also prevents soil from the soft soil foundation from entering the bamboo pile, thus extending the service life and improving the durability of the bamboo pile.

[0027] Compared with the prior art, the advantages of this utility model are:

[0028] 1. The precast bamboo pile with core sand drainage of this utility model adopts the structure of "drainage sand drainage + gradient drainage holes + filter layer". It uses capillary action to achieve directional drainage, and the drainage efficiency is significantly higher than that of traditional sand well technology. By designing the density gradient distribution of drainage holes, it can guide the foundation water out more efficiently, accelerate the foundation consolidation speed, effectively improve the bearing capacity of weak foundation, and ensure the stability of the building. The filter layer can increase the drainage time of drainage sand and improve durability.

[0029] 2. This utility model of precast bamboo piles with core sand drainage utilizes bamboo, a renewable resource, resulting in low cost, convenient transportation and construction. It reduces project costs and construction energy consumption, achieving resource conservation, environmental protection, and pollution reduction throughout the building's lifecycle, demonstrating promising application prospects and widespread value. Furthermore, the construction process for these bamboo piles is simple, requiring no large machinery and allowing for manual driving, significantly shortening the construction cycle and reducing noise pollution and environmental impact during construction.

[0030] Overall, compared to manholes, this invention's precast bamboo piles with core sand drainage, through a gradient drainage hole design, utilize capillary action to form directional drainage, thus improving drainage efficiency. The bamboo piles are lightweight and easy to transport; construction requires no large equipment and can be done manually, shortening the construction cycle. Both bamboo and core sand are low-cost materials; moreover, both bamboo and core sand are renewable materials, posing no environmental pollution risk and meeting green building requirements. The use of a filter layer improves durability. This invention retains the advantages of manhole technology while overcoming its drawbacks of complex construction, high cost, and insufficient durability, providing an efficient, economical, and sustainable solution for reinforcing soft soil foundations. Attached Figure Description

[0031] 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.

[0032] Figure 1 This is a schematic diagram of the precast bamboo pile with core sand drainage for soft foundation reinforcement in Example 1 (the non-woven geotextile layer and binding tape are not shown).

[0033] Figure 2 This is a schematic diagram of the non-woven geotextile layer and binding strap in the precast bamboo pile with core sand drainage for soft foundation reinforcement in Example 1.

[0034] Figure 3 for Figure 1 Top view.

[0035] Figure 4 for Figure 1 A bottom view.

[0036] Figure 5 This is a schematic diagram of the drainage hole structure in the precast bamboo pile with core sand drainage used for soft foundation reinforcement in Example 3.

[0037] Legend

[0038] 1. Bamboo stakes; 2. Filter layer; 3. Drainage holes; 4. Binding straps; 5. Drainage sand; 6. Concrete. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] 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.

[0043] Example 1:

[0044] like Figures 1-4 As shown, the precast bamboo pile with core sand drainage for soft foundation reinforcement in this embodiment includes a bamboo pile 1 with a hollow inner cavity. The inner cavity of the bamboo pile 1 is filled with drainage sand 5. The outer surface of the bamboo pile 1 has multiple drainage holes 3 for drainage, and the density of the drainage holes 3 increases from top to bottom (from...). Figure 1 As can be seen, the holes become more densely packed towards the bottom. The outer surface of the bamboo stake 1 is covered with a filter layer 2. The drainage sand 5 mentioned above is preferably pure fine sand.

[0045] In this embodiment, the inner cavity of the bamboo stake 1 is a hollow structure that retains only the lowest inner bamboo node while removing the other inner bamboo nodes. The inner cavity of the bamboo stake 1 is divided into an upper chamber and a lower chamber by the lowest inner bamboo node. The lower chamber is shorter than the upper chamber. The upper chamber is filled with drainage sand 5, and drainage holes 3 and a filter layer 2 are both located in the upper chamber. The lower chamber is filled with concrete 6. Preferably, the concrete 6 is made with renewable aggregate concrete.

[0046] In this embodiment, the bottom of the bamboo stake 1 is set in a pointed shape, and the concrete 6 filling the lower cavity is also in a pointed shape.

[0047] In this embodiment, the filter layer 2 is a non-woven geotextile layer, which is wrapped around the outer surface of the bamboo pile 1 by binding straps 4.

[0048] In this embodiment, both the inner and outer surfaces of the bamboo stake 1 are coated with a layer of anti-corrosion material. The choice of anti-corrosion material is not limited; for example, tung oil can be used.

[0049] In this embodiment, the diameter of the drainage hole 3 is 1-2 cm, and 10-25 drainage holes 3 are evenly provided on each section. The drainage holes 3 are set with different densities according to different heights to form a gradient drainage effect, and 10-25 drainage holes 3 are provided on each section.

[0050] This embodiment describes a precast bamboo pile with core sand drainage for reinforcing soft foundations. The precast bamboo pile involves several steps during prefabrication, including hollowing out the bamboo nodes (retaining the lowest node of the bamboo tube), drying the bamboo, drilling holes in the bamboo tube, coating the surface of the bamboo tube with anti-corrosion material, binding with non-woven geotextile, sand injection, and grouting. After prefabrication, it can be transported to the construction site and driven into the soft foundation. Once driven into the soft foundation, the pure fine sand inside the bamboo tube, through capillary action and the gradient distribution of the drainage holes 3, achieves efficient gradient drainage of the soft foundation, accelerating the consolidation process, effectively reducing the water content of the soft foundation, and enhancing the density of the soil. Simultaneously, the inherent toughness of bamboo and the structural characteristics of the bamboo tube endow the pile with excellent bending and shear resistance, allowing it to maintain structural integrity even under complex stresses and effectively resist the adverse effects of foundation settlement and lateral displacement. Even during long-term use, facing soil creep and changes in the external environment, this prefabricated structure maintains a stable working state thanks to its unique design and material properties. This embodiment fully utilizes renewable and rapidly growing bamboo, offering advantages such as convenient sourcing and green, renewable materials. Furthermore, the construction method of this embodiment is simple, quick, and cost-effective. This prefabricated structure exhibits excellent load-bearing performance and can be widely applied to reinforcement projects on various soft soil foundations. Whether for small residential buildings or large industrial facilities, it demonstrates significant reinforcement effects, providing a solid guarantee for the safety and stability of construction projects.

[0051] Example 2:

[0052] Compared with Example 1, this embodiment also includes a filter cloth in the inner cavity of the bamboo stake 1 to prevent the drainage sand 5 from leaking out through the drainage hole 3. The other structures are the same as in Example 1, which can further prevent the drainage sand 5 from leaking out and improve durability.

[0053] Example 3:

[0054] like Figure 5 As shown, compared with Embodiment 1, the drainage hole 3 in this embodiment is a horizontally arranged conical hole. The water inlet located on the outside of the bamboo pile 1 is large, and the water outlet located on the inside of the bamboo pile 1 is small. Other structures are the same as in Embodiment 1. This can further prevent the drainage sand 5 from leaking outward and improve durability.

[0055] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A precast bamboo pile with core sand drainage for reinforcing soft foundations, characterized in that, The bamboo pile (1) has a hollow inner cavity, the inner cavity of which is filled with drainage sand (5), and the outer surface of the bamboo pile (1) is provided with multiple drainage holes (3) for drainage, and the density of the drainage holes (3) increases from top to bottom. The outer surface of the bamboo pile (1) is covered with a filter layer (2).

2. The precast bamboo pile with core sand drainage according to claim 1, characterized in that, The inner cavity of the bamboo stake (1) is a hollow structure that retains only the bottom inner bamboo node and removes the other inner bamboo nodes. The inner cavity of the bamboo stake (1) is divided into an upper chamber and a lower chamber by the bottom inner bamboo node. The upper chamber is filled with drainage sand (5). The drainage hole (3) and the filter layer (2) are both located in the upper chamber. The lower chamber is filled with concrete (6).

3. The precast bamboo pile with core sand drainage according to claim 2, characterized in that, The length of the lower chamber is shorter than that of the upper chamber.

4. The precast bamboo pile with core sand drainage according to claim 2, characterized in that, The bottom of the bamboo stake (1) is set in a pointed shape, and the concrete (6) filling the lower cavity is also in a pointed shape.

5. The precast bamboo pile with core sand drainage according to any one of claims 1-4, characterized in that, The filter layer (2) is a non-woven geotextile layer, which is wrapped around the outer surface of the bamboo pile (1) by binding straps (4).

6. The precast bamboo pile with core sand drainage according to any one of claims 1-4, characterized in that, The inner cavity of the bamboo stake (1) is provided with a filter cloth to prevent the drainage sand (5) from leaking out through the drainage hole (3).

7. The precast bamboo pile with core sand drainage according to any one of claims 1-4, characterized in that, The drainage hole (3) is a horizontally arranged conical hole. The inlet on the outside of the bamboo pile (1) is large, and the outlet on the inside of the bamboo pile (1) is small.

8. The precast bamboo pile with core sand drainage according to any one of claims 1-4, characterized in that, The inner and outer surfaces of the bamboo stake (1) are coated with a layer of anti-corrosion material.

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