Drilling Device Pre-mixing Arms for Soil Mixing
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Solution Overview
Problem
Existing drilling devices for in situ soil mixing with a binder struggle to achieve optimal mixing while maintaining the ability to overcut adjacent piles effectively.
Innovation Solution
The drilling device incorporates pre-mixing means with arms having teeth, a bore-crown with cutting teeth, and adjustable features such as arm length, number of teeth, and angle to ensure effective soil-binder mixing, allowing for overcutting and continuous mixing from the shaft to the bore-crown, with optional spray openings for improved binder injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If pre-mixing means with arms and teeth are added to the bottom end of the shaft, then soil-binder mixing quality is improved, but the device complexity increases
Solution Approach 1:
The pre-mixing means are divided into multiple arms (at least two) positioned at regular intervals around the bottom end of the shaft, with each arm having teeth. This segmentation allows the mixing function to be distributed across multiple elements, improving mixing quality while keeping each individual arm relatively simple in structure.
Solution Approach 2:
The pre-mixing means perform preliminary mixing of the soil with the binder before the main mixing operation. The arms with teeth are positioned at the bottom end of the shaft to pre-mix the soil-binder mixture in advance, ensuring thorough mixing from the start and improving overall mixing quality without requiring complex continuous mixing mechanisms throughout the entire shaft length.
2Adaptability or versatility
If the bore-crown is provided with cutting means on its periphery, then the ability to overcut adjacent piles is improved, but the device complexity increases
Solution Approach 1:
The cutting means are integrated directly into the bore-crown structure, merging the overcutting function with the existing bore-crown component. This combination allows the bore-crown to simultaneously serve as the top opening of the shaft and as the cutting tool for adjacent piles, improving versatility without requiring a separate, complex overcutting mechanism.
Solution Approach 2:
The cutting means are provided on at least a part of the periphery of the bore-crown, concentrating the overcutting capability at the specific location where it is needed. This localized approach allows effective overcutting of adjacent piles while keeping the rest of the bore-crown structure simple and maintaining its primary function as the shaft opening.
3Productivity
If multiple teeth are provided on each arm of the pre-mixing means, then soil loosening and mixing effectiveness is improved, but the device complexity increases
Solution Approach 1:
Each arm is provided with multiple teeth, using excessive action to ensure thorough soil loosening and mixing. The multiple teeth on each arm create sufficient cutting and mixing action to effectively handle various soil types and conditions, ensuring productive mixing while the modular arm structure keeps the overall device complexity manageable.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration enhances soil-binder mixing quality and enables efficient overcutting of adjacent piles, ensuring a stable and thorough mixing process across the pile volume, adaptable to various soil types and conditions.
Implementation Method 1
pre-mixing means with arms having teeth... the teeth of an arm point downwardly substantially in the same direction making a sharp angle with the axis of the shaft
Implementation Method 2
injection means for injecting the binder into the loosened soil... at least one spray opening of the binder for each arm of the pre-mixing means
Data Source
Figure 1
Figure 2A~2D
Figure 3
AI summary
Drilling device for in situ mixing of soil with a binder to form a pile in the ground, comprising a drivable shaft with a bottom end, pre-mixing means mounted at the bottom end of the shaft for loosening the soil, injection means for injecting the binder into the loosened soil, a bore-crown mounted on the shaft above the bottom end, which bore-crown is provided on at least a part of its periphery with cutting means, wherein the pre-mixing means for loosening the soil comprise at least one arm having a first and a second end, said first end being connected at one end to the bottom end, said second end lying at a distance of the bore-crown, the distance between the second end and the shaft being smaller than the radius of the bore-crown, wherein said at least one arm is provided with teeth.