Transported and Residual Soil: Formation, Classification, and Engineering Implications

What Is Transported Soil?

Soil is formed through the process of weathering of the rocks, and it’s essential to understand how are soils transported. Soil is a natural resource which is present on our earth.

Weathering of the soil is the physical breakdown and chemical alteration of the earth materials at the surface level. In the process of weathering the rocks get breakdown into the smaller particles when they come in contact with the air-water or any other agent.

It is very important for Civil Engineers to study the different types of soil and their mode of transportation from one place to another place. Because Civil engineer has to deal with Foundation Engineering while constructing the structures. In this article, you will get to know all about the residual and transported soil and the Difference between the Residual soil and transported soil.

On the basis of the method of forming the soil get classified into the following types

1. Residual soil
2. Transported soil

Transported Soil Definition

Transported soils are those materials that have been moved from their place of origin, by gravity, wind, water, glaciers, or human activity either singularly or in combination. The method of transportation and deposition has a great effect on the properties of the resulting soil mass.

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Transported soil is a type of soil which is formed by the deposition of the weathered soil which is transported from one place to another place with the help of natural agents like water, wind and glaciers  Transported soil is formed at one place but transported and deposited at another place. Transported soil is developed by weathering of the sediment.

Classification of Transported Soil

The transported Soil is classified depending on the mode of transportation of the soil which is listed are as follows

1. Water transported soil
2. Wind transported soil
3. Glacial deposits
4. Gravity Deposits

1. Water Transported Soil

1. The water formed transported soil is transported by the flowing water through the river, valleys, and streams.
2. Soil may be transported in the form of suspended particles through stream and rivers.
3. When the velocity of the flowing water is more, then the large size of particles move from one place to another.
4. The soil which is Transported and deposited by the rivers are known as alluvial soil. The soil which is transported by the lake is known as Lacustrine soil.

2. Wind Transported soil

1. The soil particles which is transported with the help of wind from one place to another is known as wind transported soil.
2. In arid regions, fine-grained soils such as silt and clay are Transported by the wind.
3. In the desert regions, there is the formation of dunes due to deposition of soil like coarse sand.

3. Glacial Deposits

1. Glacial deposits from a very large group of Transported soil. Due to the melting of the glacier which causes deposition of all materials.
2. The Glacial soil has good shear strength and it can be compacted as required density. The Glaciers are the huge mass of ice which moves towards land due to melting.
3. This glaciers also Transported soil with them from one place to another place due to the melting of ice.
4. This type of soil which is transported by the Glaciers is known as Glacial soil.

4. Gravity Deposits

1. The soil, including types like talus is the soil transported by, can also be transported by means of gravity. Gravity can transport the soil only at a short distance.
2. The soil which is Transported with the help of gravity is known as Talus. This includes the deposits by the landslides.
3. It is also known as Colluvial soil which is deposited by the gravitational force. It generally consists of the coarse grained particles.
4. The Soil transported by the gravity contains different size and shape of grain particles. The movement in the case of gravity Deposits soil is less due to no external forces to move soil at a long distance.

What Is Residual Soil?

When we define residual soil, it is the material resulting from the in situ weathering of the parent rock. Residual soils are distributed throughout many regions of the world, such as Africa, South Asia, Australia, Southeastern North America, Central and South America, and considerable regions of Europe

How Is Transported Soil Is Different from Residual Soil?

The characteristics of the residual soil depend on the type of parent rock. Residual soil stays at its parent rock whereas the transported soil moved away from its parent rock. Residual soil has better engineering properties as compared to the transported soil. The soil which is deposited in its original parent rock is known as the residual soil.

Residual Soil and Transported Soil

1. Soil is formed by the weathering action and get transported from one place to another by the various transportation agencies by wind, water, glacier and gravity. This soil gets deposited at one place and known as transported soil.
2. Residual soil mostly found at the location where it formed. Generally, the residual soil depth varies from 5 m to 20 m. residual soils comprise of the wide range of the particles, shapes and composition.
3. Residual soil is the weathering product of the rocks which are found under unsaturated conditions.
4. The residual soil is formed from the weathering action of the Bedrock present below. The texture and the composition of the residual soil reflect in their parent rock.
5. The ‘transported soil’ the name itself suggests it’s meaning that it is a soil which is transported from one place to another place.
6. The method of transportation and deposition of the transported soil greatly affects its properties. Wind transported soil also formed Dunes. The sand which is deposited by the wind in the desert on the beach areas known as dunes.

What Is the Difference Between Residual Soil and Transported Soil?

 

To distinguish between transported and residual soil, the differences are as follows

FAQs: Transported and Residual Soil

What Is Transported Soil?

Transported soil refers to soil that has been moved from its original location by natural agents like water, wind, glaciers, or gravity. This movement alters its properties depending on the method of transportation and deposition.

How Is Transported Soil Classified?

Transported soil is classified based on the mode of transportation:

1. Water transported soil (e.g., alluvial soil from rivers)
2. Wind transported soil (e.g., dunes formed in desert regions)
3. Glacial deposits (e.g., materials deposited by melting glaciers)
4. Gravity deposits (e.g., talus deposits from landslides)

What Are the Characteristics of Residual Soil?

Residual soil results from the in situ weathering of the parent rock. It remains at or near its original location and retains properties influenced by its parent material. Residual soil generally has better engineering properties compared to transported soil.

How Do the Properties of Transported Soil Differ from Residual Soil?

Transported soil differs from residual soil in several ways:

1. It has undergone transportation and deposition, leading to varied grain sizes and compositions.
2. Its mineral composition can vary significantly depending on the source materials transported.
3. Unlike residual soil, it moves away from its parent rock and can be found in new locations due to natural forces.

What Are the Engineering Implications of Transported and Residual Soil?

Engineers must consider the different properties of transported and residual soil when planning construction projects:

1. Residual soil, being closer to its parent material, often has more predictable properties for foundation engineering.
2. Transported soil may exhibit variable characteristics depending on its transportation history, influencing foundation design and stability assessments.

Where Are Residual and Transported Soils Commonly Found?

Residual soils are typically found in regions where weathering processes have acted on the underlying bedrock over time. Transported soils can be found in areas influenced by natural agents like rivers, wind patterns, glaciers, and gravity-driven movements such as landslides.

How Can Soil Classification Aid in Construction Planning?

Understanding whether soil is residual or transported helps engineers anticipate its behavior under different loading conditions:

1. Residual soils may require less stabilization due to their cohesive properties.
2. Transported soils may need additional reinforcement or treatment to achieve desired stability and load-bearing capacity.

What Are Some Examples of Engineering Projects Influenced by Soil Type?

Examples include:

1. Bridge construction over rivers with alluvial soil beds.
2. Building foundations in coastal areas with wind-blown sand dunes.
3. Road construction in mountainous regions with talus deposits.

How Can Soil Testing Help in Identifying Soil Type and Properties?

Soil testing methods such as borehole logging, particle size analysis, and shear strength tests are used to determine soil type (residual or transported) and its engineering properties. This data informs decisions on foundation design, slope stability, and construction techniques.

Why Is It Important to Differentiate Between Residual and Transported Soil?

Differentiating between these soil types helps engineers assess the potential risks and challenges associated with construction projects:

1. Residual soil may offer more stable ground conditions, while transported soil may require mitigation measures to ensure structural integrity.
2. Understanding soil origins and properties supports informed decision-making in geotechnical engineering and construction planning.