Diametric Expansion Soil Compaction for Low-Disruption Ground Improvement
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Solution Overview
Problem
Existing methods for supporting structures on soft, loose, or weak soils are costly, disruptive, or ineffective, particularly in urban areas, and deep dynamic compaction can damage structures and is limited to specific soil gradations.
Innovation Solution
A soil compaction apparatus with diametric expansion/restriction elements, such as chains or wire ropes, is used to create a well-compacted column of densified soil by incremental lifting and driving, allowing for efficient compaction and densification of granular materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If deep dynamic compaction is used to compact soil, then compaction efficiency is improved, but harmful waves are generated that may damage structures
Solution Approach 1:
The patent converts the harmful impact energy from free-falling weights into beneficial compaction energy by using controlled falling weights that deliver energy through a mandrel system. The energy is contained and directed vertically into the soil through the mandrel, transforming the potentially harmful lateral wave propagation into useful vertical compaction forces that densify the soil without damaging surrounding structures.
Solution Approach 2:
The mandrel acts as an intermediary element between the falling weight and the soil. Instead of directly impacting the soil surface with free-falling weights, the mandrel transmits the impact energy in a controlled manner, mediating the energy transfer to achieve compaction while minimizing harmful wave propagation to surrounding structures.
2Reliability
If deep foundations are used to support structures on soft soils, then structural stability is improved, but construction cost increases
Solution Approach 1:
The patent changes the physical parameters of the soil by densifying it in-situ through controlled impact compaction. By altering the density and compaction state of the soft soil, the ground gains load-bearing capacity and stability, allowing structures to be supported on the improved ground rather than requiring expensive deep foundations to reach competent strata.
3Reliability
If soil excavation and replacement is performed, then foundation support is improved, but construction complexity and cost increase due to dewatering and shoring requirements
Solution Approach 1:
The patent extracts or removes the problematic soft, loose, or weak soil properties through in-situ densification. Rather than physically excavating and replacing the soil, the method extracts the excess void space and air from the soil matrix through compaction, transforming the soil in place to achieve the desired engineering properties without requiring excavation, dewatering, or shoring systems.
4Productivity
If deep dynamic compaction is used, then compaction capability is improved, but applicability is reduced due to limitation to specific soil gradations
Solution Approach 1:
The patent employs a dynamic compaction system where the mandrel is repeatedly driven into the soil and then extracted, creating a dynamic treatment process. This dynamic action allows the compaction energy to be delivered in controlled increments that can adapt to different soil conditions and gradations, making the method versatile for treating various soil types including those with fine-sized particles that are not suitable for static compaction methods.
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
The apparatus achieves efficient compaction with reduced costs and minimal disruption, enabling faster installation rates and greater load-bearing capacity compared to traditional methods.
Implementation Method 1
As the drive shaft is raised the diametric expansion elements expand radially, loosening and densifying the material below and around the drive shaft.
Implementation Method 2
As the drive shaft is raised the diametric expansion elements expand radially, loosening and densifying the material below and around the drive shaft. The material flows around and through the drive shaft as it is raised and driven back down into the ground.
Implementation Method 3
The drive shaft is then re-driven downwardly to a depth preferably less than the initial driving depth into the underlying materials.
Data Source
Figure 1A~1B
Figure 2
Figure 3A~3B
AI summary
Methods and apparatuses for compacting soil and granular materials are disclosed. In some embodiments, the soil compaction apparatuses include an arrangement of diametric expansion elements that, in their expanded state, form a larger compaction surface. In another embodiment, a compaction chamber can be provided with diametric restriction elements and a flow-through passage in the upper portion of the chamber exterior of a drive shaft. The diametric expansion or restriction elements can be fabricated from, for example, individual chains, cables, or wire rope, or a lattice of vertically and horizontally connected chains, cables, or wire rope. Embodiments of the soil compaction apparatus include, but are not limited to, closed-ended driving shafts, open-ended driving shafts, flow-through passages, no flow-through passages, removable rings for holding the diametric expansion/restriction elements, and any combinations thereof.