In Situ Horizontal Soil Barrier via Bentonite Injection

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Solution Overview

Problem

Current methods lack effective solutions for creating a temporary, continuous horizontal barrier in the subsurface to contain contaminants from migrating vertically, which limits the effectiveness of soil and groundwater remediation efforts, as existing technologies struggle with achieving 98% coverage and are not environmentally friendly or easily removable.

Innovation Solution

A method involving the installation of a low-permeability vertical barrier with a horizontal surface area, combined with the injection and mixing of permeability-reducing reagents in a grid pattern to form a continuous horizontal barrier, using environmentally friendly materials like sodium bentonite clay and enzyme-induced calcite precipitation, allowing for temporary containment and potential reversibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Duration of action of stationary object

If soil freezing is used to create a temporary horizontal barrier, then the barrier provides temporality and containment, but the effectiveness is dependent on soil saturation level which must be near 100%

Engineering Contradiction:

Improvetemporality of barrierVSAvoidapplicability to different soil conditions

Core Design Contradiction:

Duration of action of stationary objectVSAdaptability or versatility

Solution Approach 1:

The patent changes the physical-chemical parameters of the soil by injecting chemical agents (calcium chloride, sodium bentonite, cementitious materials) that alter soil permeability through precipitation, adsorption, and cementation mechanisms, making the barrier formation independent of soil saturation levels

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent replaces the mechanical freezing system with chemical systems that precipitate minerals and bind soil particles, achieving barrier formation through chemical reactions rather than physical phase change, thereby expanding applicability to various soil types and saturation conditions

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Adaptability or versatility

If chemical agents are used to modify clay properties for horizontal barrier formation, then the barrier can be formed in various soil conditions, but the environmental friendliness and reversibility are compromised

Engineering Contradiction:

Improvebarrier formation capabilityVSAvoidenvironmental impact

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent uses naturally occurring minerals (calcite, bentonite) and biodegradable polymers that change soil permeability through reversible chemical mechanisms, allowing barrier formation in various soil conditions while maintaining environmental compatibility and potential reversibility

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The patent employs biodegradable and environmentally benign materials that can naturally degrade or be reversed, replacing persistent synthetic chemicals with short-lived, eco-friendly alternatives that minimize long-term environmental impact

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Reliability

If traditional vertical barriers like sheet pilings or slurry walls are used, then lateral containment is achieved, but vertical containment of contaminants migrating downward is not provided

Engineering Contradiction:

Improvelateral containment effectivenessVSAvoidvertical contaminant migration

Core Design Contradiction:

ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent merges vertical barrier structures with horizontal barrier layers to create a three-dimensional containment system, combining the lateral containment capability of vertical barriers with the vertical migration prevention of horizontal barriers into an integrated solution

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent adds a horizontal dimension to traditional vertical barrier systems by injecting permeability-reducing agents to create subsurface horizontal barriers, transforming a one-dimensional vertical containment approach into a two-dimensional containment system

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

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 solution effectively reduces hydraulic transmissivity, achieving permeability values between 10^-7 to 10^-6 cm/sec, enabling efficient vertical containment of contaminants and allowing for temporary and reversible treatment without long-term impact on groundwater systems.

Implementation Method 1

bentonite admixture to reduce hydraulic transmissivity at depth

Methodology Applied

Scientific EffectBentonite swelling: Absorption (physical)

Implementation Method 2

enzyme-induced calcite precipitation

Methodology Applied

Scientific EffectCalcite precipitation: Precipitation

Data Source

PatentUS10399130B2Methods and systems for in situ temporary containment of shallow contaminated soils

Publication Date: 2019.09.03 CHEVRON USA INC

AI summary

A method for installing an in situ, low-permeability temporary horizontal barrier at depth for vertical containment of a soil mass including installing a low permeability vertical barrier having walls located to contain a predetermined soil volume, the vertical barrier having a horizontal surface area in a plane perpendicular to its walls; and injecting low permeability reagents capable of forming a temporary horizontal barrier in a pattern suitable for creating a horizontal subsurface barrier joined to all of the vertical barrier walls to form an in situ barrier.