Extensible Shell Pier for Granular Infill and Drainage
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Solution Overview
Problem
Existing ground improvement techniques, such as metal shells for forming concrete piles, are not extensible, corrode easily, and are not suitable for containing granular infill materials or draining cohesive soils, limiting their load-bearing capacity and durability.
Innovation Solution
An extensible shell made of non-corrosive, non-degradable material, such as plastic, that expands laterally to contain compacted granular construction material, allowing for increased load carrying capacity and drainage through apertures, enabling the construction of support piers in soft soils.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If metal shells are used for forming concrete piles, then the shells provide temporary form for cementitious material insertion, but the shells are subject to corrosion and their function is complete once concrete hardens
Solution Approach 1:
The patent changes the material parameter from ferrous metal to non-ferrous metal (such as aluminum or stainless steel), which fundamentally alters the corrosion resistance properties. This material substitution transforms the shell from a temporary, corrosion-prone formwork into a durable, long-lasting structural element that can remain in service indefinitely.
Solution Approach 2:
The patent creates a composite structure by combining non-ferrous metal shell with granular infill material (such as sand or gravel). This composite system leverages the corrosion resistance of the non-ferrous metal and the load-bearing capacity of the granular material, achieving both durability and structural performance.
2Strength
If prior art metal shells are used, then they provide form for concrete insertion, but they cannot laterally contain inserted granular materials during the life of the pier
Solution Approach 1:
The patent changes the mechanical property parameter of the shell from rigid to extensible by using non-ferrous metal with appropriate ductility. This allows the shell to expand laterally when granular material is compacted inside, creating a tight fit that provides lateral containment while accommodating the infill material's volume changes.
Solution Approach 2:
The shell transitions from a static, rigid formwork to a dynamic, extensible containment structure. During installation, the shell is inserted in its initial state, then expands dynamically as granular material is compacted inside, adapting its shape to provide optimal lateral support throughout the pier's service life.
3Reliability
If prior art shells are used, then they are made of ferrous materials, but they are not permeable and are thus ill-suited to drain cohesive soils
Solution Approach 1:
The patent applies porous or perforated metal shell material that allows water to pass through while retaining the granular infill. This porous structure provides drainage pathways for cohesive soils, preventing water accumulation and improving the overall performance of the pier in saturated ground conditions.
4Strength
If cement-based systems such as grouting or mixing methods are used, then they can carry heavy loads, but they remain relatively costly
Solution Approach 1:
The patent replaces expensive cement-based infill materials with cheaper granular materials such as sand or gravel. The non-ferrous metal shell provides the necessary structural integrity and containment, allowing the use of low-cost infill materials while achieving comparable or superior load-bearing capacity.
Solution Approach 2:
The patent creates a composite system combining non-ferrous metal shell with granular infill, replacing the traditional cement-based composite (metal shell with concrete). This substitution maintains structural performance while significantly reducing material costs and simplifying the construction process.
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 extensible shell significantly enhances the load carrying capacity of support piers by containing granular material and allowing drainage, providing a 3.5 to 5.3 fold improvement in load carrying capacity compared to traditional aggregate piers.
Implementation Method 1
The shell may be flexible such that the shell expands laterally outward when granular construction material is compacted in the interior of the shell
Implementation Method 2
The prior art shells are not permeable and are thus ill-suited to drain cohesive soils
Data Source
AI summary
Extensible shells and related methods for constructing a support pier are disclosed. An extensible shell can define an interior for holding granular construction material and define a first opening at a first end for receiving the granular construction material into the interior and a second opening at a second end. The extensible shell can be flexible such that the shell expands when granular construction material is compacted in the interior of the shell. A method may include positioning the extensible shell in the ground and filling at least a portion of the interior of the shell with the granular construction material. The granular construction material may be compacted in the interior of the extensible shell to form a support pier.