Device for preventing cement slurry loss in cement-soil mixing piles

Abstract

This utility model discloses a device for preventing the loss of cement slurry in cement-soil mixing piles, aiming to solve the technical problem of cement slurry loss due to seawater erosion during construction in near-shore environments, which affects pile quality and pollutes the environment. This utility model uses metal sheet piles to form an effective physical barrier, separating the flowing seawater from the pile foundation construction area, effectively resisting direct seawater erosion, protecting the newly formed pile body, and preventing cement slurry loss and dilution.

Description

Technical Field

[0001] This utility model relates to the field of building construction, and in particular to a device for preventing the loss of cement slurry in cement-soil mixing piles. Background Technology

[0002] In coastal areas, port terminals, and land reclamation projects, cement-soil mixing piles are a commonly used foundation treatment or retaining structure, widely applied due to their economic efficiency and ease of construction. Cement-soil mixing piles are constructed by using specialized deep mixing machinery to forcibly mix cement slurry (or dry cement powder) with soft soil in situ, forming cement-soil piles with a certain strength and water stability.

[0003] However, constructing cement-soil mixing piles in areas near seawater presents a significant technical challenge. In the early stages of pile formation, the cement-soil mixture has not yet solidified, has very low strength, and is in a fluid, plastic state. At this time, the tides, waves, and currents of the sea continuously scour and agitate the construction area. This hydrodynamic action directly washes away and dilutes the newly poured cement slurry, leading to a significant loss of cement slurry and consequently affecting the quality of the pile. Utility Model Content

[0004] The purpose of this invention is to provide a device for preventing the loss of cement slurry in cement-soil mixing piles, in order to solve the problem of cement slurry loss in areas adjacent to seawater.

[0005] To achieve the above objectives, the technical solution adopted by this utility model is as follows: a device for preventing the loss of cement slurry in cement-soil mixing piles is provided. The device includes high-strength metal sheet piles, which are disposed on the side of the cement-soil mixing pile closest to the seawater. The bottom depth of the high-strength metal sheet piles is not less than the depth of the cement-soil mixing piles, and the coverage width of the high-strength metal sheet piles is not less than the width of the cement-soil mixing piles.

[0006] In one embodiment, the high-strength metal sheet pile is made by assembling multiple metal sheets through welding or interlocking.

[0007] In one embodiment, there is a certain angle between the metal plates.

[0008] In one embodiment, the metal plate is a steel plate.

[0009] In one embodiment, the surface of the steel plate is provided with an anti-rust coating.

[0010] The above-described technical solutions in the embodiments of this utility model have at least the following technical effects or advantages:

[0011] The device for preventing cement slurry loss in cement-soil mixing piles provided in this embodiment of the invention forms a robust physical barrier by using high-strength metal sheet piles, completely isolating the flowing seawater from the pile foundation area under construction. This effectively resists the direct scouring and erosion of the newly formed cement-soil pile body by seawater waves and currents, fundamentally preventing the loss and dilution of cement slurry. By ensuring sufficient cement slurry retention within the pile body, the cement-soil mixing pile achieves the designed strength and integrity, significantly improving project quality and reliability. Furthermore, by setting up the metal sheet pile barrier, the diffusion of cement slurry into the seawater is effectively prevented, avoiding localized water alkalization and turbidity caused by cement slurry leakage. This is of great significance for protecting the marine ecological environment surrounding the construction area and meets the requirements of green and environmentally friendly modern engineering construction. Attached Figure Description

[0012] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0013] Figure 1 A front view of the device for preventing cement slurry loss in cement-soil mixing piles provided in an embodiment of this utility model;

[0014] Figure 2 A top view of the device for preventing the loss of cement slurry in cement-soil mixing piles provided in an embodiment of this utility model.

[0015] The labels for the various figures are as follows:

[0016] 1. High-strength metal sheet piles; 2. Cement-soil mixing piles; 3. Foundation pits; 4. Sand; 5. Seawater. Detailed Implementation

[0017] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain this utility model, and should not be construed as limiting this utility model.

[0018] In the description of this utility model, it should be understood that the terms "length", "width", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.

[0019] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0020] In this utility model, unless otherwise explicitly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model according to the specific circumstances.

[0021] Please see Figures 1 to 2 This application provides a device for preventing the loss of cement slurry in cement-soil mixing piles, including a high-strength metal sheet pile 1. The high-strength metal sheet pile 1 is disposed on the side of the cement-soil mixing pile 2 near the seawater 5. The bottom depth of the high-strength metal sheet pile 1 is not less than the depth of the cement-soil mixing pile 2, and the coverage width of the high-strength metal sheet pile 1 is not less than the width of the cement-soil mixing pile 2.

[0022] In one embodiment, the high-strength metal sheet pile 1 is made by assembling multiple metal sheets by welding or locking.

[0023] Commercially available standard sheet piles (such as U-shaped or Z-shaped sheet piles) inherently have interlocking clips on both sides. During construction, after driving the first sheet pile to the predetermined depth using a vibratory hammer or static pressure pile driver, the interlocking clips of the second sheet pile are aligned with those of the first. Pressure or vibration is then applied, causing the second sheet pile to slide into the ground along the interlocking clips of the first. This process is repeated for each sheet pile, forming a tightly interlocked, continuous sheet pile wall with excellent seepage prevention properties. This method offers fast construction speed, reliable connections, and the sheet piles can be extracted and reused after the project is completed.

[0024] In certain specific situations, such as when extremely high watertightness is required or when using flat steel sheets without standard locking mechanisms, welding can be used for connection. The procedure involves driving two adjacent sheet piles into the designated positions and then welding them together on-site. Welding can be done on one or both sides, and typically requires cleaning the joint of dirt and rust to ensure weld quality. To enhance connection strength and watertightness, a steel strip can be welded onto the joint. While welding provides extremely strong connection and sealing, it is slower, more expensive, and can damage the sheet pile's protective coating. Removal and reuse are also more difficult, and it is generally used in permanent or semi-permanent structures.

[0025] In one embodiment, there is a certain angle between the metal plates. By setting the metal plates to have a certain angle, the high-strength metal sheet pile 1 has a folded structure, which improves the stability of the high-strength metal sheet pile 1.

[0026] In one embodiment, the metal plate is a steel plate. Steel has excellent mechanical properties, can withstand the huge impact and vibration during the piling process, as well as the lateral pressure from seawater and soil after construction, and is not prone to bending deformation, thus ensuring the stability and safety of the entire isolation wall.

[0027] In one embodiment, a rust-proof coating is applied to the surface of the steel plate. Since the construction environment involves high-salt, high-humidity seawater, which is extremely corrosive to steel, the rust-proof coating ensures the performance and service life of the metal plate. Specific methods include hot-dip galvanizing and applying heavy-duty anti-corrosion coatings.

[0028] The device for preventing cement slurry loss in cement-soil mixing piles provided in this application utilizes high-strength metal sheet piles 1 to form a continuous multi-level seepage prevention system, preventing groundwater from seeping into the foundation pit 3 and ensuring the dryness and safety of the foundation pit 3. By driving high-strength metal sheet piles 1 into the pit before the construction of the triple-axis mixing piles, an effective multi-level seepage prevention system and retaining structure can be formed. Subsequently, the triple-axis mixing piles are constructed. After a three-dimensional ground-penetrating radar scan of the construction area and the removal of underground obstacles, a three-step treatment of "dewatering-dredging-layer backfilling" is implemented on the soft soil layer: vacuum wellpoint dewatering is used until the groundwater level is 2m below the working surface, fluid silt is removed and replaced with graded sand and gravel, with each layer having a loose thickness of ≤30cm, and compacted 6 times with a 16t vibratory roller, achieving a compaction degree of ≥95%. This further reinforces the soil around the foundation pit 3, improves the overall stability of the foundation pit 3, and prevents the loss of cement mortar.

[0029] When selecting high-strength metal sheet piles, Q345B grade weathering steel sheet piles were chosen as the main retaining structure. These sheet piles have a yield strength ≥345MPa and a zinc coating thickness ≥85μm, ensuring a service life exceeding 20 years in seawater environments with a Cl⁻ concentration ≥3.5%. Before construction, all sheet piles were inspected, and piles with defects such as cracks, interlocking deformation, or rust depth exceeding 10% of the wall thickness were removed. Locally corroded areas were sandblasted and then coated with epoxy zinc-rich primer. This ensured sufficient durability and stability in seawater environments. The driving depth and spacing of the sheet piles were determined; then, specialized piling equipment was used to drive each sheet pile into the foundation, forming a continuous retaining wall. Finally, the sheet piles were connected using welding or interlocking methods to enhance overall stability.

[0030] In the cement slurry preparation stage, 3%~5% of a nanocrystalline nucleation early-strength agent (mainly composed of CaO-Al2O3-SiO2 composite cementitious material) is added to the cement slurry. By providing nucleation sites for hydration reactions, the initial setting time is shortened to 45 minutes, and the 3-day compressive strength is increased by 40% to 15MPa, thereby improving the strength and construction period of the cement mixing pile. A dynamic database of slurry performance is established, and the proportions are adjusted for different working conditions: 0.2% calcium lignosulfonate retarder is added for high-temperature environments (>35℃); 2% sodium nitrite antifreeze is added for low-temperature environments (<5℃). Grouting is completed within 2 hours after slurry preparation, and a double-layer insulated slurry storage tank is used to maintain the slurry temperature at 10~30℃.

[0031] The above are merely preferred embodiments of the present utility model and are not intended to limit the present utility model. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A device for preventing loss of cement paste of cement-soil mixing pile, characterized by, The device for preventing cement slurry loss from cement-soil mixing piles includes high-strength metal sheet piles. The high-strength metal sheet piles are installed on the side of the cement-soil mixing pile closest to the seawater. The bottom depth of the high-strength metal sheet piles is not less than the depth of the cement-soil mixing piles, and the coverage width of the high-strength metal sheet piles is not less than the width of the cement-soil mixing piles.

2. The device for preventing cement slurry loss in cement-soil mixing piles according to claim 1, characterized in that: The high-strength metal sheet pile is made by assembling multiple metal sheets through welding or interlocking.

3. The device for preventing cement slurry loss in cement-soil mixing piles according to claim 2, characterized in that: There is a certain angle between the various metal plates.

4. The device for preventing cement slurry loss in cement-soil mixing piles according to claim 2, characterized in that: The metal plate is a steel plate.

5. The device for preventing cement slurry loss in cement-soil mixing piles according to claim 4, characterized in that: The surface of the steel plate is provided with an anti-rust coating.

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