Use of Soil Mixing and Stabilization to Improve the Geotechnical Properties of Poor Ground During Landfill Development Works
There are a variety of reasons that deep soil mixing and stabilization techniques are needed in a particular area. These may include contamination, structural necessities or other enhancement issues.
As technology has developed, it has become easier for problems of this nature to be addressed in an efficient manner. Soil engineers and environmental specialists are usually consulted before any work begins, and more and more this type of activity is being used to help supplement planned projects.
The main idea is that the entire project becomes a whole lot easier to manage by first improving upon the available ground within the landfill development. Substantial cost savings can be achieved by soil stabilzation on landfills where suitable site soils exist, and other benefits can be available in reduced traffic from avoiding the import of soils, and reductions in project program times may also be possible.
The Basics of Soil Mixing
Soil mixing is the use of a binder to achieve a much better compressive strength.
This method can be used with both cohesionless and cohesive soil types, although the former is much easier to work with. Ground in need to treatment is combined with a slurry of a cement-like substance in order to create a better quality of soil. This can also mean greater permeability and the increased capture of contaminants. This can then be excavated and replaced with better quality dirt.
The Machines that Make Deep Soil Mixing Possible
Large machines called augers bore a hole into the earth for delivery of the reagent. Giant paddles then stir up the entire load, creating a more uniform blend of materials. There is no one solution for any area, so the amount of additives will vary in proportion to the desired consistency. The other issue is how deep the treatment needs to be. At this time, depths of approximately 100 feet have been successfully completed.
Many times, the soil has to undergo stabilization techniques in addition to the mixing process. This is intended to improve properties and engineering characteristics of an area. It is most often used to treat a contaminated area. The additive choice here may be, for example, Portland cement as it helps to bind up toxic materials, making the soil less permeable with a greater compressive strength. Lime is another additive used for soil stabilization where appropriate.
By using the best combination of soil binder here, the ground can be taken out and used in a landfill or possibly re-used on site for greater development. As an added bonus, the structural properties of this area are greatly increased as well.
Benefits of Soil Mixing
By combining soil mixing and stabilization techniques are becoming mush more often applied and engineers are now able to reclaim land that was deemed unusable. This allows for conservation of natural resources, which is one of the primary forces driving the current “green” movement and should flourish with proper attention.
Why Soil Mixing Projects Require the Involvement of an Engineering Geologist
The practice of soil mixing involves the interpretation, evaluation, analysis, and application of geological information and data to civil works. Geotechnical soil and rock units need to be designated, characterized, and classified, using standard engineering soil and rock classification systems.
Relationships need to be interpreted between landform development, current and past geologic processes, ground and surface water, and the strength characteristics of soil and rock.
Proposed developmental modifications will need to be evaluated and, where appropriate, analyzed to predict potential or likely changes in types and rates of superficial geologic processes.
Site-specific engineering geologic actions will for the typical soil-mixing improvement project for a landfill development, include soil mixing for cuts, fills, roadways, and utility lines; foundations for structures and other drainage structures, retaining walls and shoring, buildings, slopes, drainage channels and other temporary slope stabilization needs.
All this means that the Engineering Geologist will be an important member of the site project team throughout all such landfill projects.