SLOPE STABILIZATION METHODS

The following examples are offered as information only and your specific application should be analyzed and verified by a Professional Engineer prior to construction of any gabion structure. 

Note: Geo-textile filter fabric shall always be placed underneath the gabion or mattress slope protection to prevent loss of soil during drainage or hydraulic impact. 

Slope Protection Applications

There are many different ways that gabions are used for slope protection. Some of these applications include:

• Retention structures - Gabions retain water during heavy rains and snowfall.
• Retention ponds - Gabions are used in ponds to prevent erosion and damage caused to the surrounding area.
• Dams - Gabions are used as dams to store runoff.
• Erosion Control - Gabions are used for erosion control purposes.

Why Is Slope Protection Important?

Landslides occur when slopes weaken and fail, a catastrophe that can cause massive damage to structures and possible deaths. Stabilizing slopes is crucial to protecting those living in landslide-prone areas and to preserving the environment. Slope stabilization also protects transportation systems and prevents harmful sediment from entering rivers, lakes, and other water bodies.   

Causes of Slope Failures

In addition to natural erosion and weathering, causes of slope failures include:

• Seismic activity and rainfall: Natural calamities, such as earthquakes and heavy rainfall, can weaken slopes, which leads to mass wasting or landslides.
• Poor drainage: A poor drainage system can cause flooding during heavy rains, causing soil to move and leading to slope failure. 
• Excavation mistakes: Improper construction practices, such as excessive excavation without temporary slope reinforcement, can also cause landslides. 

Types of Slope Protection 

Leaning poles or trees, unusual water pooling, and cracks in the ground are warning signs of a potential mass wasting. You can protect slopes by using:

• Concrete barriers: Concrete blocks placed on the slope or on the retaining wall help stabilize the soil and prevent soil erosion that causes landslides.
• Vegetation: The root systems provided by trees, grasses, and shrubs bind the soil, providing a protective layer that reduces or prevents erosion. 

Gabion systems: Unlike retaining walls, water flows through the gabion structure, reducing water pressure. Gabions are effective at protecting slopes because they can withstand the weight and pressure of the soil. 

How Do Landslides Occur?

The most common reason for landslides is excessive rainwater. Rainwater tends to collect on slopes, especially on ones that have been eroded due to their steepness. As more and more rainwater collects, the rate at which the soil moves increases. When enough force is exerted on the ground, it breaks apart or slides down the slope. This process may occur several times before the entire slope collapses under its own weight.

What Are Gabions Used For?

Gabions are used for slope stabilization and erosion control. They are constructed by filling the cages with stones. The stones act as a barrier and prevent the soil from moving up and down the slope.

When Should I Use Gabions?

When constructing a new slope, you can use gabions to help stabilize the area instead of using other retaining walls and barriers. You can also use them to stabilize the surface soil to protect from a large amount of rainfall. If your slope already has a lot of vegetation growing in it, you can use them to protect the area from eroding or sliding and by acting as velocity dissipators.

How Gabion Retaining Walls Mitigate Landslides

In addition to protecting slopes, gabions are used to mitigate landslides. In areas where there is a risk of landslides occurring, gabions are placed on the soil to create a check dam. The dams slow and direct the flow of water, thereby preventing landslides. The soil does not get overly saturated and therefore cannot break away by controlling the water flow. The gabions also provide stability to the area around them. They keep the ground in place while allowing water to flow freely, keeping the soils where they belong.

Advantages of Gabion or Reno Mattress Slope Protection

Stabilization of Eroding Areas

The gabions prevent the soil from eroding and sliding into the river.

Prevention of Flooding

Floodwaters do not penetrate far into the gabions, and they can hold back and stabilize slopes and walls to prevent flooding.

Erosion Control

Erosion control is achieved by placing gabion structures on the surface of slopes and channels to reduce water speed and retain soil particles.

Cost-Effectiveness

The cost of installing gabions can be much lower than that of other methods like earthen berms or retaining walls. Gabions can also be built quickly, whereas other methods can require weeks or months.

How Gabion Slope Protection Systems Work

Gabion slope protection systems can help stabilize soil and prevent erosion by promoting vegetation growth and stabilizing the soil. Water simply seeps through gabions, minimizing water erosion. Gabion protection systems are flexible and can adapt to ground settling without compromising their structural integrity. They're highly durable, preventing soil from slipping and eventually causing landslides. If you have questions about gabion protection systems, please don't hesitate to reach out.