Multi-Diameter Cast In-Situ Pile Drilling With Nested Auger Tools
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing methods for constructing cast in-situ piles with varying diameters along their depth are time-consuming and resource-intensive, often requiring multiple drilling stages and additional support mechanisms, which can lead to environmental impacts and inefficiencies.
Innovation Solution
A continuous flight auger drilling method using a coupling-decoupling device allows a single drilling rig to insert and operate multiple tools with different diameters sequentially, enabling a single-phase construction process that reduces material consumption and drilling time, while efficiently transferring loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If multiple drilling stages with tool replacement are used to construct piles with varying diameters, then manufacturing precision is improved, but productivity deteriorates due to repeated extraction and replacement of drilling tools
Solution Approach 1:
The patent implements nesting by placing a smaller diameter drilling tool inside the hollow stem of a larger diameter drilling tool. The smaller tool is inserted through the hollow stem and can be coupled to the larger tool, allowing both tools to be operated simultaneously as a single assembly. This eliminates the need to extract and replace tools between drilling stages, thereby maintaining manufacturing precision for variable diameter piles while significantly improving productivity by avoiding repeated tool extraction and replacement operations.
2Reliability
If temporary steel casing or drilling slurry is used to support borehole walls, then reliability is improved, but device complexity worsens due to additional support mechanisms
Solution Approach 1:
The nested drilling tool configuration allows the smaller diameter tool to be operated within the hollow stem of the larger tool, enabling continuous drilling through variable soil conditions without requiring external support mechanisms. The hollow stem provides structural integrity while the nested arrangement allows for seamless transition between drilling stages, maintaining borehole stability through the drilling process itself rather than requiring additional steel casing or slurry systems.
Solution Approach 2:
The patent enables continuous drilling action by coupling the smaller and larger diameter tools together, allowing the drilling operation to proceed without interruption through multiple soil layers. The coupled tools can be extracted as a single assembly and replaced with another coupled assembly for the next depth range, maintaining continuous useful action without the need for intermediate support mechanisms that would interrupt the drilling process.
3Reliability
If drilling slurry is used to support borehole walls, then reliability is improved, but loss of substance worsens due to consumption of water and bentonite
Solution Approach 1:
The nested drilling tool system eliminates the need for drilling slurry by providing structural support through the hollow stem configuration itself. The larger diameter tool's hollow stem encloses the smaller diameter tool, creating a self-supporting structure that maintains borehole integrity without requiring external slurry. This significantly reduces or eliminates consumption of water and bentonite that would otherwise be needed to prepare and maintain drilling slurry.
4Manufacturing precision
If conventional methods with multiple drilling stages are used, then manufacturing precision is improved, but loss of time worsens due to repeated tool extraction and replacement
Solution Approach 1:
The nested configuration allows smaller and larger diameter drilling tools to be coupled together and operated as a single integrated assembly. This eliminates the time-consuming operations of extracting, replacing, and re-positioning tools between drilling stages. The coupled assembly can be drilled to the required depth for each diameter segment, then extracted as one unit and replaced with the next appropriate coupled assembly, dramatically reducing the drilling cycle time while maintaining precise control over pile diameter variations.
Solution Approach 2:
The patent applies preliminary action by pre-coupling the smaller and larger diameter drilling tools together before insertion into the ground. This preparation is done in advance at the surface, allowing the coupled assembly to be inserted and drilled without interruption. The next coupled assembly is also prepared in advance, enabling seamless transition between depth ranges and eliminating idle time during tool changes.
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
This invention is detailing a construction method for a cast in-situ pile having an upper section with a larger diameter and at least one subsequent section with a smaller diameter, and a drilling device equipped with continuous flights which allows the construction of one pile having multiple diameters using the innovative construction method in a single continuous drilling phase while each drilling tool is penetrating through the soil in one pass. The drilling tool according to the invention has a central hollow space that allows accommodation through it of at least one another smaller diameter drilling tool that can drill continuously and can be coupled by means of a coupling-decoupling device in a specific manner to the other drilling tool in order to act as a fixed assembly, at any given position in relation to the smaller drilling tool length and rotating position.