How can you use sustainable materials to improve geotechnical engineering?

Improvement with the natural, recycled and bio-based needs to have sone durability checks. Some reinforced methods are not suitable for high seismicity areas.

As the Earth has a limited supply of naturally occurring materials and the world's population and amount of infrastructure continues to grow, it has become increasingly important to use sustainable materials in their place for as much of our building materials as possible. Our need for landscape modification is likely only to grow in the future as the world becomes more advanced. The need for proper shelter and business structures will grow. We likely will have to rely more on manmade materials in place of naturally occurring materials to meet this demand. In addition to the increased use of manmade, replenishable materials, we also need to focus on an increased efficiency of land use, thus reducing the size of modifications required.

I live in a third world tropical country. Many of our rural roads are made with the naturally occurring soils nearby. Lack of compaction and moisture control means we lose large amounts of the soil to erosion. I am particularly interested in soil stabilizers that are easy to apply and are effective across a range of soil types, particularly silty and clayey tropical soils. So far the Perma-Zyme soil stabilizer is a very interesting product. Political will, inherent corruption, and poor engineering culture will be a huge hurdle to cross in bringing this product to my country.

Here are some ways in which modern technology is used to improve soil improvement: For example, crushed concrete can be used as a sustainable alternative to traditional fill materials. Targeted soil improvement methods, such as dynamic compaction or vibro-compaction, can densify loose soils using sustainable equipment and techniques. However, Modern soil mixing machines can efficiently blend and stabilize soils by injecting binders or cementitious materials. They are equipped with precise control systems to ensure uniform mixing. Also, advanced deep soil mixing methods combine multiple augers and advanced mixing blades to improve soil strength and stiffness. Real-time monitoring systems are used to assess the quality of soil mixing.

An example of slope stabilization project that I involved was the use of fragmented limestone that we utilize to support a slope excavated through an old Pyrite Concetrate tailings dam of 40m high. The use of limestone was preferred applicable to manage environmental risk of Acid Rock Drainage (ARD) as a neutralising agent due to the high contration of Pyrite (FeS2). Also the the competent limestone was used as a buttress support for the slope increasing it's stiffness and also allow free drain thus improve it's stability. Now the slope is very stable with negligible ARD concerns.

Sustainable soil nails and anchors made from recycled materials can reinforce slopes by transferring loads to stable ground. They are a cost-effective and environmentally friendly alternative to traditional retaining walls. Also, sustainable drainage systems (SuDS) can be integrated into slope stabilization projects. These systems manage water effectively, reducing the risk of erosion and landslides while promoting groundwater recharge. Moreover, combining biology and engineering, bioengineering involves using native vegetation, seeds, cuttings, or mulch to provide root reinforcement, surface protection, and erosion control. It enhances ecological value and reduces reliance on synthetic materials.

Will the acidic water dissolve the limestone ? I remember a case of a UK earth dam where crushed limestone was used in some trench filter drains. Sulphuric acid generated from breakdown of pyrites in the mudstone earth fill attacked the limestone and rendered it ineffective as a filter.

Another prospective of foundation design is what design approach you are following, the ASD approach or the LRFD approach. Recently, the LRFD is the way to do for design as the eurocode and the AASHTO are following this approach.

Sustainable foundation design can start with the use of recycled concrete or other construction waste as aggregates in the foundation mix. This reduces the demand for virgin materials and minimizes waste. Also, consider using sustainable reinforcement options such as recycled steel or non-metallic reinforcements like fiberglass or basalt rebar. These materials can be as strong as traditional steel reinforcement and have a lower environmental impact. On the hand, proper foundation insulation can reduce energy consumption and improve the thermal performance of a building, contributing to sustainability.

Sustainable waste management involves the responsible handling, disposal, and recycling of waste materials to minimize environmental impact and promote resource conservation. Sustainable packaging materials, such as biodegradable plastics, recycled cardboard, or reusable containers, can be used to minimize waste generation in construction and other industries. Moreover, organic waste generated during construction, landscaping, or demolition can be composted to create nutrient-rich soil amendments. Also, Sustainable materials like biodegradable erosion control matting can facilitate this process. Establish programs that encourage the reuse and salvage of materials from one project to another.

In selection of suitable sites for waste disposal consider sites that are already deteriorated by human activities, for example quarries or aggregate excavation sites. To protect underground waters consider use of geomembranes created from recycled materials like recycled PE and PEHD. Usual protection from landfill leachate waters entering (mixing with) underground waters is creation of protection layer consisting of clay layers with thickness of up to 1 meter and one layer of PEHD membrane. This should be sustainable for hundreds of years. If someone tells you that this is not enough consider adding additional layers despite rise of costs. This costs are incomparable to value of revitalization of degraded nature,

Redeveloping former landfills & impacted industrial sites reduces urban sprawl, & forces you to think outside the box, rather than relying on typical greenfield methods such as undercutting, deep foundations, & conventional pavements because the cost or practicality of conventional improvements is economically unfeasible. We utilize dynamic compaction, rigid inclusions & aggregate piers. We use flexible pavement sections & crushed concrete agg to bridge the subgrade, & we use bentonite plugs to prevent offsite migration. We manufacture agg on-site at industrial sites, & use crushed concrete & milled asphalt instead of imported natural agg. Our goal is to retain everything on-site, which reduces trucking & fuel use.