A conical bidirectional mixing head for cement mixing pile construction

Abstract

This utility model discloses a conical bidirectional mixing head for cement mixing pile construction, comprising a hollow outer rod, within which a hollow inner rod is nested. A vertical main shaft is fixedly connected to the end of the inner rod, which serves as the mixing shaft and is a hollow shaft with a closed conical end. The inner rod is coaxially fixedly connected to the top of the vertical main shaft, and their inner cavities are interconnected. Straight blades and a grouting pipe communicating with the inner cavity of the vertical main shaft are vertically mounted on the vertical main shaft. The straight blades are the main mixing blades. A positioning sleeve is fitted onto the vertical main shaft. The outer rod and the positioning sleeve are fixedly connected through the free end of a C-shaped mixing blade, which is a secondary mixing blade. This mixing head achieves bidirectional rotation while improving and optimizing its structural form, resulting in stronger mixing capacity and anti-drilling characteristics, which is beneficial to the stability and uniformity of pile formation and can improve construction efficiency to a certain extent.

Description

Technical Field

[0001] This utility model relates to the technical field of cement mixing pile construction equipment, and in particular to a conical bidirectional mixing head for cement mixing pile construction. Background Technology

[0002] Cement mixing pile method is a mature soil reinforcement technology, widely used in soft soil foundation reinforcement and seepage prevention curtain engineering. It relies on a specially designed cement mixing pile machine to complete the construction. Currently, most conventional cement mixing pile machines on the market are unidirectional rotating machines. That is, during construction, the mixing head of the cement mixing pile machine can only rotate in one direction (clockwise or counterclockwise), which in turn drives the mixing blades to rotate in one direction. The mixing blades, rotating in one direction, mechanically cut and turn the cement slurry (or cement powder) with the soil to force it to mix and form a pile. Although unidirectional cement mixing pile machines have a simple structure and low equipment investment, due to the single design of the mixing head (a few bidirectional cement mixing pile machines also have similar problems), they only rotate in one direction during construction, resulting in poor mixing uniformity and easy formation of mixing blind zones. This leads to the presence of unevenly mixed "plain soil interlayers" or "cement lumps" in the cement-soil mixture. The uneven distribution of cement slurry results in poor uniformity and large dispersion in the strength, cement content, and density of the cement-soil mixture at different locations (along depth and radial direction) of the pile body. This can easily lead to the formation of "candied hawthorn string" shaped pile bodies (with large strength fluctuations) or the presence of localized weak interlayers. In addition, in highly plastic clay, silt, and organic soil, blades rotating in one direction can easily tightly wrap and compact the cohesive soil around the drill rod and blades, forming a "soil column". This severely hinders the sinking or lifting of the drill rod, a phenomenon known as "drill clamping". This can lead to irregular pile diameter (local necking or widening), unclear pile outline, and increased verticality deviation of the pile. It can also greatly reduce construction efficiency, increase energy consumption, and may even cause accidents such as drill rod breakage, equipment damage, and pile interruption. Utility Model Content

[0003] To address the aforementioned technical problems, this utility model proposes a conical bidirectional mixing head for cement mixing piles. While achieving bidirectional rotation, the mixing head has stronger mixing capacity and anti-drilling characteristics through improved and optimized structural form, which is beneficial to the stability and uniformity of pile formation and can improve construction efficiency to a certain extent.

[0004] A conical bidirectional mixing head for cement mixing pile construction includes a hollow outer rod, inside which is a hollow inner rod. The end of the inner rod is fixedly connected to a vertical main shaft, which serves as a mixing shaft and is a hollow shaft with a closed conical end. The inner rod is coaxially fixedly connected to the top of the vertical main shaft and its inner cavity is through-connected. The vertical main shaft is vertically provided with straight blades and a grouting pipe communicating with the inner cavity of the vertical main shaft. The straight blades are the main mixing blades. A positioning sleeve is sleeved on the vertical main shaft. The outer rod and the positioning sleeve are fixedly connected through the free end of a C-shaped mixing blade, which is a secondary mixing blade.

[0005] As a preferred embodiment of the above technical solution, the C-shaped stirring blades are provided in two sets, and the longitudinal sections of the two sets of C-shaped stirring blades are located on the same plane and are symmetrically arranged with respect to the vertical main axis.

[0006] As a preferred embodiment of the above technical solution, the straight blades are provided in multiple sets, and the cross-section of the straight blades is set at a certain angle to the cross-section of the vertical main shaft.

[0007] As a preferred embodiment of the above technical solution, the straight blades are provided in multiple groups, and each group of straight blades includes two straight blades arranged opposite to each other, and the two straight blades in the same group have the same angle with the cross section of the vertical main shaft and opposite inclination.

[0008] As a preferred embodiment of the above technical solution, the vertical main shaft is provided with multiple sets of straight blades in the rod section between the C-shaped stirring blades and the rod section on the vertical main shaft below the positioning sleeve.

[0009] As a preferred embodiment of the above technical solution, the two adjacent sets of straight blades are arranged in a cross shape.

[0010] As a preferred embodiment of the above technical solution, the grouting pipe is disposed close to the upper surface of the last straight blade on the vertical main shaft, and the length of the grouting pipe is less than the length of the straight blade.

[0011] The beneficial effects of this utility model are as follows:

[0012] This mixing head, while achieving bidirectional rotation, features an improved and optimized structure, resulting in enhanced mixing capacity and anti-drilling properties. The bidirectional shearing motion effectively replaces and compacts the soil, leading to regular pile formation, minimal pile diameter fluctuation, and better pile verticality. This reduces irregularities such as "string of candied hawthorns" or localized necking and widening. It offers significant advantages, particularly when dealing with complex strata such as high-water-content silt, high-plasticity clay, thin sand interlayers, or organic soils, promoting pile stability and uniformity and improving construction efficiency to a certain extent. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the structure of this utility model.

[0014] Figure 2 This is a top view of the present invention.

[0015] The attached diagram is labeled as follows: 1-outer rod, 2-inner rod, 3-vertical main shaft, 4-straight blade, 5-grouting pipe, 6-positioning sleeve, 7-C-type mixing blade. Detailed Implementation

[0016] The technical solution of this utility model will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0017] like Figure 1 The cone-shaped bidirectional mixing head for cement mixing pile construction shown includes a hollow outer rod 1, inside which a hollow inner rod 2 is nested. The end of the inner rod 2 is fixedly connected to a vertical main shaft 3, which serves as a mixing shaft and is a hollow shaft with a closed cone-shaped end. The inner rod 2 is coaxially fixedly connected to the top of the vertical main shaft 3 and the inner cavity is through it. The vertical main shaft 3 is vertically provided with straight blades 4 and a grouting pipe 5 communicating with the inner cavity of the vertical main shaft 3. The straight blades 4 are the main mixing blades. A positioning sleeve 6 is sleeved on the vertical main shaft 3. The outer rod 1 and the positioning sleeve 6 are fixedly connected through the free end of a C-shaped mixing blade 7, which is a secondary mixing blade.

[0018] In this embodiment, the C-shaped stirring blades 7 are provided in two sets, and the longitudinal sections of the two sets of C-shaped stirring blades 7 are located on the same plane and are symmetrically arranged with respect to the vertical main axis 3.

[0019] In this embodiment, the straight blade 4 is provided in multiple sets, and the straight blade 4 is set at a certain angle to the cross section of the vertical main shaft 3.

[0020] In this embodiment, the straight blades 4 are provided in multiple groups. Each group of straight blades 4 includes two straight blades 4 arranged opposite each other, and the two straight blades 4 in the same group have the same angle with the cross section of the vertical main shaft 3 and are inclined in opposite directions.

[0021] In this embodiment, the vertical main shaft 3 is provided with multiple sets of straight blades 4 in the rod section between the C-shaped stirring blades 7 and the rod section of the vertical main shaft 3 below the positioning sleeve 6.

[0022] In this embodiment, adjacent sets of straight blades 4 are arranged in a cross shape, such as... Figure 2 As shown.

[0023] In this embodiment, the grouting pipe 5 is disposed close to the upper surface of the last straight blade 4 on the vertical main shaft 3, and the length of the grouting pipe 5 is less than the length of the straight blade 4.

[0024] The working principle of this embodiment is as follows.

[0025] The conical bidirectional mixing head is installed on a bidirectional cement mixing pile machine. The bidirectional cement mixing pile machine has two concentrically nested drill rods: an outer drill rod and an inner drill rod. The outer drill rod is a larger diameter round pipe, connected at its end to the outer rod of the conical bidirectional mixing head. The inner drill rod is a relatively smaller diameter round pipe, concentrically nested inside the outer drill rod. The inner cavity of the inner drill rod contains a grouting main pipe, which is connected to the inner rod 2 of the bidirectional mixing head. The grouting main pipe communicates with the cavity of the inner rod 2, and further communicates with the grouting pipe 5 fixed on the vertical main shaft 3, forming a channel for injecting cement slurry (or cement powder) into the soil. The outer and inner drill rods can rotate simultaneously in both directions, thereby driving the conical bidirectional mixing head installed at the end of the drill rods to rotate in both directions. Simultaneously, the grouting pipe 5 injects cement slurry (or cement powder), and the straight blades 4 and C-shaped mixing blades 7 on the conical bidirectional mixing head rotate in both directions to cut and mix the soil.

[0026] The counter-rotating blades create a "kneading," "tearing," and "turning" effect on the soil, more effectively breaking down the soil's granular structure and stratification. This allows the cement slurry (or cement powder) to be mixed more thoroughly and evenly with the soil in both horizontal and vertical directions, resulting in a more complete hydration reaction. This significantly reduces the occurrence of mixing blind zones and inhomogeneous materials (such as soil clumps and cement blocks), reduces local enrichment of cement slurry (or cement powder) or insufficient contact with the soil, improves cement utilization, and ensures that the cement-soil pile body is more uniform in material composition and physical and mechanical properties (strength, modulus) along the pile length and diameter. It also reduces weak points and defects, making the pile body a more integrated composite foundation reinforcement or seepage prevention curtain.

[0027] Compared to unidirectional mixing, bidirectional mixing offers stronger mixing capabilities and better anti-drill-clamping properties, resulting in smoother drill rod sinking and lifting, and higher construction efficiency. The bidirectional shearing motion effectively replaces and compacts the soil, leading to more regular piles with less diameter fluctuation and better verticality, reducing irregularities such as "string of candied hawthorns" or localized necking and widening. It is particularly advantageous when dealing with complex strata such as high-water-content silt, high-plasticity clay, thin sand interlayers, or organic soils, ensuring higher pile quality.

[0028] The above are merely preferred embodiments of this utility model and are 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 conical bidirectional mixing head for cement mixing pile construction, characterized in that: The device includes a hollow outer rod, within which a hollow inner rod is nested. The end of the inner rod is fixedly connected to a vertical main shaft, which serves as a stirring shaft and is a hollow shaft with a closed conical end. The inner rod is coaxially fixedly connected to the top of the vertical main shaft and its inner cavity is open. The vertical main shaft is vertically provided with straight blades and a grouting pipe communicating with the inner cavity of the vertical main shaft. The straight blades are the main stirring blades. A positioning sleeve is fitted on the vertical main shaft. The outer rod and the positioning sleeve are fixedly connected through the free end of a C-shaped stirring blade, which is a secondary stirring blade.

2. The conical bidirectional mixing head for cement mixing pile construction according to claim 1, characterized in that: The C-shaped stirring blades are provided in two sets, and the longitudinal sections of the two sets of C-shaped stirring blades are located on the same plane and are symmetrically arranged with respect to the vertical main axis.

3. The conical bidirectional mixing head for cement mixing pile construction according to claim 2, characterized in that: The straight blades are provided in multiple sets, and the straight blades are set at a certain angle to the cross-section of the vertical main shaft.

4. A conical bidirectional mixing head for cement mixing pile construction according to claim 3, characterized in that: The straight blades are provided in multiple groups. Each group of straight blades includes two straight blades arranged opposite each other. The two straight blades in the same group have the same angle with the cross section of the vertical main shaft and are inclined in opposite directions.

5. A conical bidirectional mixing head for cement mixing pile construction according to claim 3, characterized in that: The vertical main shaft is provided with multiple sets of straight blades in the section between the C-shaped stirring blades and in the section of the vertical main shaft below the positioning sleeve.

6. The conical bidirectional mixing head for cement mixing pile construction according to claim 4, characterized in that: The adjacent groups of straight blades are arranged in a cross shape.

7. The conical bidirectional mixing head for cement mixing pile construction according to claim 1, characterized in that: The grouting pipe is positioned close to the upper surface of the last straight blade on the vertical main shaft, and the length of the grouting pipe is less than the length of the straight blade.

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