Viscosity Regulator for Jet Grouting Binder Stability

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Solution Overview

Problem

The formation of solidified binder-soil mixture bodies, such as those used in jet grouting for construction pit enclosures, is hindered in areas with high water content or water-bearing soils, as the binder can be washed out before solidification, preventing the creation of continuous, elongated bodies.

Innovation Solution

A method and injection arrangement that incorporate a viscosity regulator, which increases the viscosity of the binder without accelerating hardening, are used. This is achieved by adding the viscosity regulator to the binder and/or binder-soil mixture, often through a separate line conveying it with compressed air, to prevent washing out during the formation of elongated binder-soil mixture bodies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If binder is introduced into water-rich soil areas, then soil stabilization is achieved, but binder is washed out before solidification

Engineering Contradiction:
Improvestability of binder-soil mixture bodyVSAvoidloss of binder due to washing out
Core Design Contradiction:
ReliabilityVSLoss of substance

Solution Approach 1:

The patent changes the viscosity parameter of the binder by adding viscosity-regulating agents (such as cellulose ethers, starch derivatives, or synthetic polymers). This increases the binder's resistance to water flow, preventing washout while maintaining pumpability within certain viscosity ranges (typically 10-1000 mPa·s). The viscosity is adjusted to balance between erosion resistance and injectability.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent introduces viscosity-regulating agents as intermediary substances that modify the binder's physical properties. These agents act as mediators between the binder and water-rich soil environment, creating a rheological barrier that reduces water-binder interaction and prevents premature washout before solidification occurs.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Loss of substance

If viscosity regulator is added to increase binder viscosity, then washout is prevented, but hardening process may be affected

Engineering Contradiction:
Improvereduction of binder washoutVSAvoidhardening time of binder
Core Design Contradiction:
Loss of substanceVSDuration of action of stationary object

Solution Approach 1:

The patent applies local quality by selecting viscosity regulators with specific chemical structures and molecular weights that provide the desired viscosity enhancement without interfering with the binder's hardening chemistry. Different viscosity regulators are chosen based on their compatibility with specific binder types (cement-based, chemical, or organic binders) to ensure localized optimization of both viscosity and hardening properties.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent carefully controls the dosage and concentration of viscosity regulators to achieve the desired viscosity increase while maintaining acceptable hardening times. By adjusting the amount of viscosity regulator added and selecting agents with appropriate molecular characteristics, the patent optimizes the balance between erosion resistance and setting time to ensure construction feasibility.

Inventive Principle:
Principle #35Parameter changes

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 increased viscosity of the binder-soil mixture enhances stability and prevents washing out, allowing for the formation of stable, continuous elongated bodies even in water-rich environments, thereby improving the construction of excavation pit enclosures.

Implementation Method 1

a viscosity regulator that increases viscosity but does not accelerate hardening, i.e. does not accelerate hardening of the base mass, is added to the binder and/or the binder-soil mixture

Methodology Applied
Scientific EffectViscosity regulation:

Data Source

PatentEP3880890B1Method and device for injecting soils
Publication Date: 2023.08.02 PORR BAU
  • EP3880890B1 patent drawingFigure 1~3
  • EP3880890B1 patent drawingFigure 2

AI summary

The invention relates to a method for forming consolidated combined binder-soil bodies, in particular elongated bodies, in particular for forming excavation pit enclosures by jet grouting, comprising the steps of inserting, in particular drilling, an injection lance into the soil, and subsequently withdrawing the injection lance from the soil while simultaneously introducing a binder, in particular a binder suspension, into the surrounding soil material along the withdrawal path, thereby forming, in the soil, an elongated section of a combination of binder and soil material, a viscosity-increasing, non-curing-accelerating viscosity regulator, i.e. which does not accelerate the curing of the matrix, being added to the binder and/or binder-soil combination. The invention also relates to an injection assembly for forming consolidated combined binder-soil bodies, in particular elongated bodies.