Spiral mixing drum drill for cement mixing pile construction
The innovative design of the spiral mixing drum drill solves the problem of uneven quality in the lower part of the pile caused by the structure of the cement mixing pile drill bit, achieving stable quality throughout the entire length of the pile and improving construction efficiency. It is suitable for large-scale foundation reinforcement in coastal and riverside areas.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 王鹏
- Filing Date
- 2026-03-04
- Publication Date
- 2026-05-15
AI Technical Summary
The existing structure of cement mixing pile drill bits results in better quality at the top of the pile but difficulty in forming the bottom, which can easily lead to necking or pile breakage.
The spiral mixing drum drill, including an outer casing, spiral mixing blades, upper and lower cross mixing teeth, and grouting nozzles, is designed with a hollow structure. The grouting nozzles are evenly arranged around the circumference. The spiral mixing blades rotate in opposite directions to the outer casing. Combined with a three-dimensional mixing system, it ensures that the grouting pressure is matched with the stress gradient of the soil layer.
It achieves uniform and stable mass throughout the entire length of the pile, improves the homogeneity and overall strength of the pile in all directions, simplifies the construction process, reduces construction period and cost, and is suitable for large-scale foundation reinforcement in soft soil areas such as coastal and riverside areas.
Smart Images
Figure CN122039984A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of civil engineering technology, specifically to a spiral mixing drum drill for cement-soil mixing pile construction. Background Technology
[0002] Cement mixing piles are the most common and widely used method for reinforcing weak foundations both domestically and internationally, and are frequently used in railway engineering, highway engineering, municipal engineering, and many other fields. In particular, many large and medium-sized cities in my country are located along the coast and rivers, covering nearly half of the prefecture-level cities nationwide, which are the most densely urbanized areas.
[0003] Cement mixing piles utilize specialized mixing equipment to forcibly mix soft soil with cement-based materials, followed by a series of chemical reactions to form cylindrical piles with a certain strength. This construction process maximizes the use of the original soil, is vibration-free and pollution-free, and has minimal impact on surrounding existing buildings and underground structures. Due to its unique advantages and strong applicability, it has become the most common method for reinforcing silty soft soil.
[0004] Existing cement-soil mixing pile drill bits typically employ cross-shaped mixing teeth. However, as the mixing depth increases, the grouting pressure at the drill bit becomes mismatched with the soil depth, resulting in better quality in the upper part of the cement-soil mixing pile (generally above 6.0m), but poor quality in the lower part. This is the main reason why some piles fail to form their lower sections, leading to pile necking or breakage. Therefore, we propose a spiral mixing drum drill for cement-soil mixing pile construction to address these problems. Summary of the Invention
[0005] To address the shortcomings of existing technologies, this invention provides a spiral mixing drum drill for cement-soil mixing pile construction. This solves the problem that existing mixing pile drill bits only use cross-shaped mixing teeth, and the grouting pressure is not matched with the soil depth as the mixing depth increases. This results in the upper part of the pile being of good quality, but the lower part is difficult to form, and necking or pile breakage is likely to occur.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution: a spiral mixing drum drill for cement-soil mixing pile construction, including an outer casing;
[0007] Spiral stirring blades are disposed inside the outer protective cylinder;
[0008] The upper cross-shaped stirring teeth are fixed to the top of the spiral stirring blades, and their exterior is connected to the outer casing via bearings.
[0009] The lower cross-shaped stirring teeth are fixed to the bottom of the spiral stirring blades, and are connected to the outside of the blades by bearings and an outer protective sleeve.
[0010] The spray nozzle is located between the spiral mixing blades and the lower cross-shaped mixing teeth.
[0011] Preferably, the upper cross-shaped stirring teeth and the lower cross-shaped stirring teeth can be staggered in the circumferential direction.
[0012] Preferably, the spiral stirring blades are designed with a hollow structure, and the spray nozzles are located on the surface of the spiral stirring blades.
[0013] Preferably, multiple spray nozzles are evenly arranged around the circumference of the spiral stirring blades.
[0014] Preferably, the cross-sectional shape of the lower cross-shaped stirring teeth is one of rhombus, triangle or streamline.
[0015] Preferably, the spiral stirring blades are divided into at least two pitch segments from top to bottom, and the pitch variation rate between adjacent pitch segments is 10% to 30%.
[0016] Beneficial effects
[0017] This invention provides a spiral mixing drum drill for cement-soil mixing pile construction. Compared with the prior art, it has the following advantages:
[0018] The spiral mixing drum drill used in the construction of this cement-soil mixing pile has achieved significant optimization through innovative structural design. The counter-rotating cooperation between the outer casing and the spiral mixing blades effectively reduces the interference of lateral soil stress and the self-weight stress above on the grouting pressure, establishing a stable relationship between grouting pressure and soil stress gradient. This fundamentally solves problems such as difficulty in forming deep piles, necking, and pile breakage, ensuring uniform and stable quality throughout the entire pile length. Simultaneously, the outer casing and spiral mixing blades jointly constrain the grouting range, and the multiple grouting nozzles evenly distributed around the spiral mixing blades ensure precise and consistent grouting volume per meter of pile foundation, further improving the standardization of pile cross-sectional dimensions.
[0019] The three-dimensional mixing system, consisting of spiral mixing blades, upper cross-shaped mixing teeth, and lower cross-shaped nail-shaped mixing teeth, combined with the circumferentially staggered tooth layout and streamlined optimized design of the lower nail-shaped teeth, achieves thorough mixing of soil and cement grout in both the circumferential and radial directions, significantly improving the homogeneity and overall strength of the pile. Furthermore, the efficient synergistic design of mixing and spraying simplifies the traditional "two-mixing-two-spraying" or "two-mixing-four-spraying" process to a single sinking and lifting operation, greatly improving efficiency. While ensuring construction quality, it significantly reduces construction time and costs, making it more suitable for large-scale foundation reinforcement projects in soft soil areas such as coastal and riverside regions. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the overall structure of the present invention;
[0021] Figure 2 This is a cross-sectional view of the overall structure of the present invention.
[0022] In the diagram: 101, outer casing; 102, spiral mixing blades; 103, upper cross-shaped mixing teeth; 104, spray nozzle; 105, lower cross-shaped mixing teeth. Detailed Implementation
[0023] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0024] like Figure 1-2 As shown:
[0025] A spiral mixing drum drill for cement-soil mixing pile construction includes an outer casing 101;
[0026] The spiral stirring blade 102 is disposed inside the outer casing 101;
[0027] The upper cross-shaped stirring teeth 103 are fixed to the top of the spiral stirring blades 102, and their exterior is connected to the outer casing 101 through bearings;
[0028] The lower cross-shaped stirring teeth 105 are fixed to the bottom of the spiral stirring blades 102, and their exterior is connected to the outer casing 101 through bearings;
[0029] The upper cross-shaped stirring teeth 103 and the lower cross-shaped stirring teeth 105 can be staggered in the circumferential direction;
[0030] The spray nozzle 104 is located between the spiral stirring blade 102 and the lower cross-shaped stirring tooth 105. The spiral stirring blade 102 has a hollow structure design, and the spray nozzle 104 is opened on the surface of the spiral stirring blade 102. Multiple spray nozzles 104 are evenly arranged along the circumference of the spiral stirring blade 102.
[0031] The cross-sectional shape of the lower cross-shaped stirring teeth 105 is one of rhombus, triangle or streamline.
[0032] The spiral stirring blade 102 is divided into at least two pitch segments from top to bottom, and the pitch variation rate between adjacent pitch segments is 10% to 30%.
[0033] In this implementation plan: When using the spiral mixing drum drill for cement-soil mixing pile construction, the construction site should be leveled and cleaned to ensure that there are no obstacles in the construction area and that the installation and working space requirements of the drill are met. The integrity and connection reliability of each component of the drill should be checked, including the outer casing 101, spiral mixing blades 102, upper cross mixing teeth 103, grout nozzle 104, and lower cross-shaped mixing teeth 105, etc., to ensure that the bearing connection is smooth and there is no jamming. The gear mechanism at the drill rod connection (not shown in the figure) should be adjusted to ensure that it can accurately realize the reverse rotation function of the spiral mixing blades 102 and the outer casing 101. At the same time, the grouting system should be checked to ensure that the cement slurry supply is stable and the grouting pressure can be accurately adjusted according to the construction requirements.
[0034] The drilling power system is activated, and the outer casing 101 and the spiral mixing blade 102 are driven to rotate in opposite directions via the gear transmission structure at the drill rod connection. The reverse rotation of the outer casing 101 effectively breaks through the soil resistance, providing guidance and protection for the drilling tool's descent, and preventing soil collapse from affecting the pile formation.
[0035] Under its own weight and the power system, the drill bit begins to sink, with the lower cross-shaped stirring teeth 105 making contact with the soil and cutting and breaking it. Due to its rhomboid, triangular, or streamlined cross-section design, it can effectively reduce sinking resistance, improve cutting efficiency, and quickly break through the surface and deep soil layers.
[0036] During the sinking process, the shotcrete system is started simultaneously, and the cement slurry is transported to the shotcrete nozzle 104 through the hollow structure of the spiral mixing blade 102. The shotcrete nozzles 104 are evenly arranged around the spiral mixing blade 102 to ensure that the slurry can be sprayed evenly in all directions;
[0037] The outer casing 101 remains wrapped around the outside of the drill bit throughout the descent process, reducing the interference of lateral soil stress on the grouting pressure. Simultaneously, the reverse rotation of the spiral mixing blades 102 prevents the transfer of the soil's own weight stress to the grouting area, thus avoiding any impact on the grouting pressure. Based on the preset matching relationship between the grouting pressure and the soil stress gradient, the grouting pressure remains stable, ensuring the uniformity of the grouting volume per meter at different depths.
[0038] During the sinking process, the spiral mixing blades 102 continuously mix the soil. The upper cross-shaped mixing teeth 103 and the lower cross-shaped mixing teeth 105 are arranged in a circumferentially staggered manner, forming a three-dimensional mixing system with the spiral mixing blades 102. The soil broken up by the lower cross-shaped mixing teeth 105 is transported to the upper part by the spiral mixing blades 102, and then further mixed by the upper cross-shaped mixing teeth 103 to ensure that the cement slurry and the soil are fully mixed in the circumferential and radial directions, achieving homogeneity in all directions.
[0039] When the drill bit descends to the designed pile length depth, the outer casing 101 and the spiral mixing blade 102 maintain their opposite rotation. The lifting system is then activated, and the drill bit is slowly lifted. During the lifting process, the grouting system continues to operate, with the grout nozzle 104 continuously and evenly spraying cement grout. Due to the constraint of the outer casing 101 and the spiral mixing blade 102, the grouting range is limited to the designed cross-section of the pile body, preventing grout loss and ensuring that the grouting volume per meter remains consistent with the descending stage. During the lifting process, the spiral mixing blade 102, the upper cross-shaped mixing teeth 103, and the lower cross-shaped mixing teeth 105 perform secondary mixing of the soil and cement grout mixture. At this point, the soil and grout have been initially mixed. The opposite rotation of the mixing structure further breaks down agglomerates in the mixture, allowing the cement grout to fully penetrate and fuse with the soil, improving the density and uniformity of the pile body. As the drill bit is gradually lifted, the mixed cement-soil mixture forms a pile with a certain strength and cross-sectional dimensions at the pile location, until the drill bit is completely lifted to the ground, completing the construction of a single pile.
[0040] This solution achieves significant optimization through innovative structural design. The counter-rotating cooperation between the outer casing 101 and the spiral mixing blades 102 effectively reduces the interference of lateral soil stress and the self-weight stress above on the grouting pressure, establishing a stable relationship between grouting pressure and soil stress gradient. This fundamentally solves problems such as difficulty in forming deep piles, necking, and pile breakage, ensuring uniform and stable quality throughout the entire pile length. Simultaneously, the outer casing 101 and the spiral mixing blades 102 jointly constrain the grouting range. Combined with the multiple grouting nozzles 104 evenly arranged circumferentially on the spiral mixing blades 102, this ensures precise and consistent grouting volume per meter of pile foundation, further improving the standardization of pile cross-sectional dimensions.
[0041] The three-dimensional mixing system, consisting of spiral mixing blades 102, upper cross-shaped mixing teeth 103, and lower cross-shaped nail-shaped mixing teeth 105, combined with the circumferentially staggered tooth layout and streamlined optimized design of the lower nail-shaped teeth, achieves thorough mixing of soil and cement grout in both the circumferential and radial directions, significantly improving the homogeneity and overall strength of the pile. Furthermore, the efficient synergistic design of mixing and spraying simplifies the traditional "two-mixing-two-spraying" or "two-mixing-four-spraying" process to a single sinking and lifting operation, greatly improving efficiency. While ensuring construction quality, it significantly reduces construction time and costs, making it more suitable for large-scale foundation reinforcement projects in soft soil areas such as coastal and riverside regions.
[0042] It should be noted that: the lower end of the drill rod (not shown in the figure) is rigidly fixed to the central shaft of the spiral mixing blade 102, and the internal hollow channel is connected to the hollow structure of the blade for conveying slurry. The gear mechanism (not shown in the figure) is located at the junction of the lower end of the drill rod and the top of the outer casing 101. The driving gear is fixed to the drill rod, and the driven gear is fixed to the inner side of the top of the casing and meshes with the driving gear. The gearbox provides protection and positioning. The outer casing 101 is externally connected to the upper cross-shaped mixing teeth 103 and the lower cross-shaped nail-shaped mixing teeth 105 through bearings to achieve positioning and relative rotation. The drive system drives the drill rod to rotate, which synchronously drives the driving gear and the spiral mixing blade 102 to rotate. Through gear meshing transmission, the driven gear drives the outer casing 101 to rotate in the opposite direction, forming a reverse shearing motion. The multi-pitch section design of the blade is adapted to the mixing intensity of different soil layers. The slurry nozzle 104 sprays slurry evenly as the blade rotates, and the cross-shaped mixing teeth rotate synchronously with the blade, cooperating with the counter-rotating casing to achieve thorough mixing of soil and slurry in all directions, ensuring construction quality and efficiency.
[0043] Finally, it should be noted that the above descriptions are merely preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.
Claims
1. A spiral mixing drum drill for cement-soil mixing pile construction, characterized in that: Including the outer casing (101); Spiral stirring blades (102) are disposed inside the outer casing (101); The upper cross-shaped stirring teeth (103) are fixed to the top of the spiral stirring blades (102), and are connected to the outside of the blades by bearings and the outer casing (101); The lower cross-shaped stirring teeth (105) are fixed to the bottom of the spiral stirring blade (102), and are connected to the outside of the blade by bearings and the outer casing (101); The spray nozzle (104) is located between the spiral stirring blade (102) and the lower cross-shaped stirring teeth (105).
2. The spiral mixing drum drill for cement-soil mixing pile construction according to claim 1, characterized in that: The upper cross-shaped stirring teeth (103) and the lower cross-shaped stirring teeth (105) can be staggered in the circumferential direction.
3. The spiral mixing drum drill for cement-soil mixing pile construction according to claim 1, characterized in that: The spiral stirring blade (102) has a hollow structure design, and the spray nozzle (104) is opened on the surface of the spiral stirring blade (102).
4. The spiral mixing drum drill for cement-soil mixing pile construction according to claim 3, characterized in that: The spray nozzles (104) are evenly arranged in multiple directions along the circumference of the spiral stirring blades (102).
5. The spiral mixing drum drill for cement-soil mixing pile construction according to claim 1, characterized in that: The cross-sectional shape of the lower cross-shaped stirring teeth (105) is one of rhombus, triangle or streamline.
6. The spiral mixing drum drill for cement-soil mixing pile construction according to claim 1, characterized in that: The spiral stirring blade (102) is divided into at least two pitch segments from top to bottom, and the pitch variation rate between adjacent pitch segments is 10% to 30%.