Soil types such as man-moved, backfill, and native layers have various properties that make them suitable for different construction work. Let’s look at three soil types and what you can expect from them.
Your foundation is the backbone of the house and what holds the entire structure. This means you must be careful about your choice of materials, the building process, and the blocks that go into it. But one important thing that some people overlook is the soil supporting the foundation.
Your foundation has to be built on strong and stable soils to support the load above. Soils differ in strength, and not all can support a building. Building your foundation on unstable soils may cause your building to sink, develop cracks, and, even worse, collapse. To avoid all these, you must understand the different soil types and their physical properties.
This refers to any soil that’s dug up and moved to different locations for various human activities, including construction. With the population increase in urban areas, some places are not easy to develop because they lack good soil. They need massive excavation, disposal, and replacement before any construction can be done. This is where man-moved or fill soils come in.
There are three types of man-moved soils.
Engineered Fill Soil: These types of man-moved soil are used to replace non-engineered soils in construction sites. The main purpose here is to get good soil that can support structures. They consist of subgrade soils or granular materials lifted for minimal compaction levels. When done correctly, engineered fills make perfect soil for foundation support.
Dumped Fills: Loamy and silty soils make the best cover for landfills as they have less gravel and stones. These soils are highly variable by nature and can be re-engineered and used in foundations.
Hydraulic Fills: Any soil that’s used to raise the level of low-lying land or to build new land is regarded as hydraulic fills. They’re mostly dredged from water bodies during land reclamation and characterized by size or heterogeneous soils. Hydraulic fills can be multilayered soils with organics and deleterious materials. Soils from hydraulic deposits are sometimes used as native soil.
Backfilling entails putting soil back around the foundation after excavation work is complete. In other words, builders replace or reuse excavated soils after construction to strengthen the foundation. Backfilling is done to strengthen the soil and restore its stability. Here are different types of materials used for backfilling.
Coarse-Grained Soil: This type of soil is commonly used in backfilling and has low plasticity. It comes in the form of a soil mixture of sand and gravel and some fine materials. Since this soil is compact, it’s suitable for creating a backfill and supporting the foundation.
Fine Graded Soil: Any soil with particles smaller than 0.075 mm falls into this category. Silt, sand, and various clay soils are good examples. Both have low-to-medium plasticity and are useful materials for backfills. They also include inorganic clays that are fairly compacted with heavy equipment to create a stable backfill.
Commercial By-Products: Lightweight by-products like furnace slag or fly ash are usually sold as backfilling material. They are sometimes used as additives for highly plastic clay and when constructing 25-foot-high walls. Their suitability for backfilling may depend on the engineering characteristics of the products and the desirable characteristics of the backfill.
Native Soil Layers
These are soils from a true native field or soil modified from the native field. With true native or undisturbed soil, the constructors only use the soil available on the site. Modifying native soil entails infusing available soil with peat, sand, compost, or porous ceramic soils. This modification creates a better and stable base for construction.
The decision to use native soil depends on several factors such as the condition of the on-site soil, the weather, and how often the site is in use. Native soil is less expensive.
Other Soil Sub-Categories
Here are other types of soil you’ll find.
This is a common type of soil found. It’s quite troublesome as it tends to shrink when dry and swell when wet. Because of this, clay on its own doesn’t make good construction soil.
This type of soil is suitable for construction thanks to its wonderful properties. It doesn’t react in any way with moisture.
Sand doesn’t shrink or swell. However, it can erode over time. Proper drainage is required to stop the erosion.
This soil has an almost equal amount of sand and silt. While it holds moisture and drains pretty well, it’s prone to erosion and doesn’t offer adequate support to your home.
It’s a flaky type of sedimentary rock that contains quartz, clay, and other minerals that compact together over time. This composition puts shale in the category of rocks known as mudstones, which are fissile and laminated. Shale tends to shrink and swell if it has too much clay in it.
Is your home built on stable soil? If not, it can show signs of failure and settlement such as cracks and uneven floors. For help addressing these issues, contact JES Foundation Repair for a free foundation inspection and repair estimate on recommended solutions.