Traditionally, ineffective & costly methods have been utilized in treating expansive soil. Methods such as removing it completely and replacing it with fill dirt, pre-wetting and pre-swelling the soil and injecting or mixing of lime or other solutions into existing soils.

Which type of foundation will be used on expansive soil?

Strip footing is suitable when the soil, through expansive, little swelling pressure. When the soil swells, the sand grains would yield by moving up, thus reliving the swelling pressure. These type of foundations are mostly used for medium loads.

What are the problems with expansive soils?

Because of this swelling and shrinking behaviour, expansive soils may cause the following problems in structures or construction projects: Structural damage to lightweight structures such as sidewalks and driveways. Lifting of buildings, damage to basements, and building settlement. Cracks in walls and ceilings.

How do you build a house on expansive soil?

There are very effective strategies for building reliable structures in expansive soil zones.

1. Shaft piers and void. Primary among those is the use of drilled shaft piers.
2. Over-excavation. Another system is using spread footers that are sized to create sufficient load to resist movement.
3. Slab construction.

What types of soil are expansive?

There are three basic types of soil naturally occurring in this area: sand, silt and clay. Clay soils are generally classified as “expansive.” This means that a given amount of clay will tend to expand (increase in volume) as it absorbs water and it will shrink (lessen in volume) as water is drawn away.

How can you help avoid Foundation issues due to shrink swell soil?

One of the easiest ways to protect your foundation from shrink swell soil is to make sure that your drainage system is in good working order.

1. Clear your gutters.
2. Point the downspouts away from your home.
3. Extend downspouts – if possible – at least 5 feet away from your home.

What is difficult soil?

‘Difficult’ means those that may be hard to work with or those that, because of their poor structure, are either too wet or too dry for good plant growth, or lacking in essential humus or organic matter. Soils can be divided into four main types: clays, sands, chalk soils and loams.

What is the best foundation for clay soil?

What type of foundation is best for clay soil? Usually clay has a higher moisture content and when the moisture content becomes stable upto certain depth it becomes suitable for the substructure. Raft foundation is best to use when the clayey soil is compact and hard. Even strap foundation can also be used.

What causes expansive soils?

Expansive soils swell when exposed to large amounts of water and shrink when the water evaporates. This continuous cycle of wet to dry soil keeps the soil in perpetual motion causing structures built on this soil to sink or rise unevenly, often requiring foundation repair.

What causes foundation damage?

Insufficient Soil Structure– If the soil beneath your foundation is low density or it isn’t compacted properly, it can lead to foundation damages. Transpiration– If the trees near your house aren’t properly watered they can take all of the water from the ground. This causes the soil to shrink away from the foundation.

Can you build on expansive soils?

It is possible to build a home safely on expansive soil as long as you can maintain stable moisture. In order to provide structural protection to your expansive soil based property, you need to keep the following in mind: Test and classify soil. Design to reduce moisture content and insulate against volume changes.

Why is clay bad for foundations?

Clay absorbs water easily, expanding in volume as it becomes more saturated. So-called “expansive clays” can cause foundations to crack, heave and shift. When clay soils dry out, they shrink and crack, leaving gaps around a house where water from the next storm can penetrate easily and repeat the expansion cycle.

What is expansive soil give an example?

Soils are composed of a variety of materials, most of which do not expand in the presence of moisture. However, a number of clay minerals are expansive. These include: smectite, bentonite, montmorillonite, beidellite, vermiculite, attapulgite, nontronite, and chlorite.

Why are expansive soils dangerous?

These soils swell when they get wet, with increases in volume of 10% or more. That’s enough pressure to crack concrete foundation walls and floor slabs and even cause foundation movement, resulting in damage to the upper floors of a home or building. To make matters worse, expansive soils also shrink when they dry out.

What is the shrink swell soil?

Shrink swell soil is the movement caused by the amount of water in the soil. A lot of rain or a very dry season can change how your soil acts around your foundation. Soil shrinkage occurs when the water is removed from the ground. This can be caused by a drought, heatwave, or just an extended dry period.

How can we prevent soil shrinkage?

These movements are caused by changes in soil moisture. Providing uniform soil moisture next to and under your foundation is the single best thing you can do to reduce the effect that shrink/swell soil movements have on your structure.

What are the 6 types of soil?

There are six main soil types:

• Clay.
• Sandy.
• Silty.
• Peaty.
• Chalky.
• Loamy.

  Is it OK to build a house on clay soil?

  Effects of Clay Soil on Your Home’s Foundation Of all soils, clay has the most damage potential for your foundation. Expansive clay soils expand with moisture and will cause your foundation to heave, crack and shift. When the clay dries out, it shrinks and leaves gaps where water can enter to cause even more damage.

  How do expansive soils work?

  Expansive soils contain minerals such as smectite clays that are capable of absorbing water. When they absorb water, they increase in volume. The more water they absorb, the more their volume increases. This change in volume can exert enough force on a building or other structure to cause damage.

  Why is expansive soil a concern if it underlies a home?

  Structural damage like cracked foundations, basement walls, and floors are some typical signs that you have expansive soil. Once expansive soil dries out, it shrinks. This shrinkage can remove some of the foundational support of the building and causes further structural damage.

  When it comes to clay soil, the best house foundation would be between a drilled pier foundation or a slab-on-grade foundation. Drilled pier foundations will anchor deeper into the clay for more structural stability while slab-on-grade foundations combat clay soil’s tendency to shrink and expand.

  How does expansive soil cause damage to foundations?

  This creates cyclic shrink/swell behavior in the upper portion of the soil column, and cracks can extend to much greater depths than imagined by most engineers. Foundation Damage The most obvious way in which expansive soils can damage foundations is by uplift as they swell with moisture increases.

  What can I do about expansive soil around my house?

  Other home owners may lay out a soaker hose around their foundation and manually turn it on and off. The reason for doing this is to keep the moisture content of the soil around the foundation constant, avoiding very dry and wet cycles that create swelling and shrinkage of the soil.

  How does expansive soil affect concrete floor slabs?

  Surface tension is a contributor to this process. Expansive soils can damage foundations and concrete floor slabs through uplift or lateral expansion. In a typical year in the U.S., expansive soil causes greater financial loss than than hurricanes, floods, earthquakes, and tornados combined.

  What causes the foundation of a house to tilt?

  Secondly the entire foundation doesn’t drop down evenly, but has high and low areas resulting in the foundation sloping or tilting in some areas or cracking due to the stress from uneven soil support. Uneven movement (non-uniform movement) can also be caused by differential swelling due to pockets of moist soil next to areas of dry soil.