Expanded Multilayer Integral Geogrids for Stiffness and Compressibility

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Solution Overview

Problem

Current integral geogrids face limitations in achieving enhanced stiffness, compatibility with a variety of aggregates, and compressibility under load, while also being cost-effective, due to constraints in material type and structure within the geogrid cross-section.

Innovation Solution

The development of expanded multilayer integral geogrids with at least one expanded inner layer, featuring a distribution of voids or particulate filler, which allows for increased layer compressibility and compatibility with aggregates, while maintaining or reducing overall polymer content.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a conventional monolayer integral geogrid structure is used, then the manufacturing process is simple and cost is lower, but the geogrid lacks enhanced compressibility and stiffness characteristics

Engineering Contradiction:

ImprovestiffnessVSAvoidstructure

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The geogrid is divided into multiple layers with different properties: outer layers provide structural strength and stiffness, while an inner expanded layer provides compressibility. This segmentation allows each layer to perform its specific function optimally, resolving the contradiction between stiffness and compressibility.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention uses a composite structure combining dense polymer layers with an expanded foam layer. This composite construction integrates materials with different density and compliance characteristics, enabling simultaneous achievement of high stiffness and high compressibility that cannot be obtained with a single material.

Inventive Principle:

Principle #40Composite materials

2Strength

If the geogrid uses more polymer material to increase stiffness, then strength improves, but cost increases and compressibility decreases

Engineering Contradiction:

ImprovestiffnessVSAvoidpolymer content

Core Design Contradiction:

StrengthVSQuantity of substance

Solution Approach 1:

Different regions of the geogrid have different polymer densities and properties. The outer layers use dense polymer for stiffness and strength, while the inner layer uses expanded foam for compressibility. This local differentiation allows the geogrid to achieve desired mechanical properties without uniformly increasing polymer content throughout.

Inventive Principle:

Principle #3Local quality

3Adaptability or versatility

If the geogrid structure is simplified to reduce manufacturing complexity, then production cost decreases, but the ability to engage with various aggregates is reduced

Engineering Contradiction:

Improveaggregate compatibilityVSAvoidstructure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The inner expanded layer provides a porous structure that can adapt to various aggregate sizes and densities. This porous configuration allows the geogrid to engage with different aggregate types while maintaining a relatively simple overall manufacturing process, as the expansion can be achieved through foaming agents during extrusion.

Inventive Principle:

Principle #31Porous materials

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 expanded multilayer integral geogrids provide improved structural performance, including higher aspect ratios, better aggregate stabilization, and economic benefits by using the same or less polymer, while maintaining or enhancing stiffness and compressibility.

Implementation Method 1

at least one inner layer having a structure that is expanded relative to at least one other layer of the multiple layers, so as to provide an integral geogrid having increased layer compressibility under load

Methodology Applied

Scientific EffectCompressibility:

Implementation Method 2

The voids may be associated with a foamed construction of the layer, or may be associated with a particulate filler that is distributed throughout the layer in order to create the expansion of the layer

Methodology Applied

Scientific EffectStress distribution:

Data Source

PatentUS20250230620A1Expanded multilayer integral geogrids and methods of making and using same

Publication Date: 2025.07.17 TENSAR INTERNATIONAL CORP

AI summary

An expanded multilayer integral geogrid includes a plurality of oriented strands interconnected by partially oriented junctions having an array of openings therein that is produced from a coextruded or laminated multilayer polymer starting sheet. The integral geogrid has a multilayer construction, with at least one inner layer thereof having a structure that is expanded relative to at least one other layer of the multiple layers. By virtue of the expanded inner layer structure, the expanded multilayer integral geogrid provides for increased layer compressibility under load, resulting in enhanced material properties that provide performance benefits to use of the expanded multilayer integral geogrid in soil geosynthetic reinforcement, and economic benefits compared to a like integral geogrid without an expanded inner layer structure.