Geosynthetic Element for Uniform Microbe Cement Distribution

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing methods for soil reinforcement in geotechnical engineering, such as direct introduction of calcifying bacteria, face limitations in achieving uniform calcium carbonate precipitation and bacterial distribution, leading to inefficient soil stabilization and increased costs due to the need for extensive drilling and repetitive injections.

Innovation Solution

A geosynthetic element comprising bacteria carriers and a flow network, allowing for controlled implementation of microbiologically induced calcium carbonate precipitation (MICP) with predetermined bacterial placement and circulation, reducing the need for extensive drilling and enabling homogeneous distribution of calcifying bacteria and microbe cement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Quantity of substance

If calcifying bacteria are directly introduced into the soil via single injection well, then bacteria can be applied to the soil, but calcium carbonate precipitation is limited to vicinity of injection source and bacterial propagation is poor

Engineering Contradiction:
Improvecalcium carbonate precipitationVSAvoidbacterial distribution uniformity
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The geosynthetic element is segmented into multiple bacteria carriers distributed throughout the soil matrix, each capable of releasing calcifying bacteria locally. This segmentation transforms the single-point injection into a distributed multi-point release system, enabling uniform bacterial distribution and calcium carbonate precipitation throughout the treated soil volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The geosynthetic element acts as an intermediary carrier system between the injection well and the soil. It includes a flow network that distributes reactant solutions and a bacteria carrier network that releases calcifying bacteria at predetermined locations, mediating the delivery process to achieve homogeneous bacterial distribution and controlled calcium carbonate precipitation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Quantity of substance

If heavy feeding equipment and repetitive injections are used to improve larger soil volumes, then calcium carbonate precipitation can be enhanced, but installation costs and time consumption increase

Engineering Contradiction:
Improvecalcium carbonate precipitation volumeVSAvoidinjection repetition time
Core Design Contradiction:
Quantity of substanceVSLoss of time

Solution Approach 1:

The geosynthetic element is installed in advance as a permanent infrastructure containing pre-positioned bacteria carriers and flow network channels. This preliminary action eliminates the need for repetitive injections, as the element continuously releases bacteria and distributes reactants over an extended period, significantly reducing installation time and operational repetitions.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The geosynthetic element enables continuous calcium carbonate precipitation through its integrated flow network that continuously distributes reactant solutions and bacteria carriers that continuously release calcifying bacteria. This continuous action replaces discrete repetitive injections, maintaining useful action over extended periods without requiring repeated equipment operations.

Inventive Principle:
Principle #20Continuity of useful action

3Ease of manufacture

If bacteria are directly fed into soil at installation site, then application can be performed, but quality control tests and process monitoring become difficult

Engineering Contradiction:
Improveapplication simplicityVSAvoidquality control capability
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The geosynthetic element is manufactured as a standardized replica system with predetermined bacteria carrier locations and flow network configuration. This factory-produced copy allows quality control tests to be performed on the element itself before installation, ensuring consistent bacterial distribution and reactant flow characteristics without requiring complex field monitoring of the actual soil treatment process.

Inventive Principle:
Principle #26Copying

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

This approach enhances soil stability and mechanical properties by ensuring uniform microbe cement distribution, reducing costs through factory-based quality control and flexible application strategies, and improving load-bearing capacity and erosion resistance with reduced site monitoring.

Implementation Method 1

MICP is a natural process based on microbial-induced urea hydrolysis (Equation 1). This natural reaction mechanism is catalysed by the enzyme urease found in several bacterial strains.

Methodology Applied
Scientific EffectUrea hydrolysis: Hydrolysis

Implementation Method 2

A catalysed urea hydrolysis completes 10 14 produced by the urea hydrolysis precipitates into solid calcium carbonate crystals (Equation 2) under the presence of a calcium source, such as calcium chloride.

Methodology Applied
Scientific EffectEnzyme catalysis: Enzyme

Implementation Method 3

A catalysed urea hydrolysis completes 10 14 produced by the urea hydrolysis precipitates into solid calcium carbonate crystals (Equation 2)

Methodology Applied
Scientific EffectPrecipitation: Precipitation

Implementation Method 4

A catalysed urea hydrolysis completes 10 14 produced by the urea hydrolysis precipitates into solid calcium carbonate crystals (Equation 2)

Methodology Applied
Scientific EffectCrystallisation: Crystallisation

Data Source

PatentEP3631094B1geotextile
Publication Date: 2021.09.29 ECOLE POLYTECHNIQUE FEDERALE DE LAUSANNE (EPFL)
  • EP3631094B1 patent drawingFigure 1~3
  • EP3631094B1 patent drawingFigure 4~5b
  • EP3631094B1 patent drawingFigure 6a~6d

AI summary

The present invention concerns a geosynthetic element (1) for a geotechnical engineering application. The geosynthetic element (1) comprises: bacteria carriers (3) for carrying bacteria arranged to be propagated from the geosynthetic element (1) to a surrounding geomaterial; and a flow network comprising openings on its surface to allow a reactant to escape the flow network to the surrounding geomaterial along the flow network to produce solid calcium carbonate when in contact with the bacteria. The reactant flow network further comprises a set of inlets for feeding the reactant into the flow network, and a set of outlets for recovering at least a part of the reactant from the reactant flow network.