Ground Improvement Tool: Vibro Stone Columns
Vibro stone columns are an array of pillars made of crushed stone placed into the soil with a vibrating tool below a proposed structure. Helitech uses vibro stone columns in a variety of projects for cost-effective and durable solutions.
Vibratory stone columns (or vibro stone columns, vibro replacement stone columns, vibro-piers, or aggregate piers) are compacted columns of aggregate that are installed through existing soils to improve the geotechnical properties of the soil matrix.
The stone columns consist of a series of vertical lifts of compacted aggregate from a pre-determined depth up to the ground surface. They are installed utilizing a specialized vibratory probe called a “vibroflot.”
This vibroflot is utilized to create a borehole down to a specific depth, the aggregate is then introduced, and the vibroflot compacts the rock. The aggregate compaction process repeats until the dense column of rock is built up to the ground surface.
Vibro-piers are currently one of the most commonly used ground improvement systems in the world today. They are designed to improve the load-bearing capacity of the surrounding soil and reduce excessive settlement.
Why Should You Use Vibro Stone Columns?
Vibro stone columns are one of the most widely used forms of ground improvement and reinforcement in modern construction and engineering.
- Can meet a wide variety of needs without compromising quality
VSCs can be applied to a variety of projects, and as an added benefit, they are a financially savvy, economical alternative to more expensive deep foundation systems.
- Ideal for mixed fills and granular soils
VSCs can usually be constructed to depths of up to 50 feet. In most cases, settlement can be improved by a factor of 1.5 to 3.0 – with bearing pressures between 3,000 – 8,000 psf achievable.
- Quick and efficient installation
In contrast to deep foundation systems, aggregate piers can be installed in a fraction of the time. This is particularly advantageous for construction projects under strict deadlines.
- Reduced spoils
In many soil conditions, the stone columns can be installed by driving the flot into the ground without bringing up spoils. Reducing the cost of handling and hauling off spoils. This can be especially beneficial on site with contaminated soils.
- Time rate of settlement
Where large loads will be applied, such as embankment construction, stone columns will reduce total settlements and accelerate the time rate of settlement, reducing construction delays.
Uses and Benefits of Vibro Stone Columns
Since their inception, vibro-piers have found a number of different uses. Some of the most common include:
- Increasing bearing capacity
Vibro stone columns are used often to increase the load-bearing capacity of a particular area, which, by nature, isn’t strong enough to bear the load of a proposed structure. Vibro stone columns provide improved bearing capacity by increasing the strength of the soil through the insertion of compacted granular material or stone.
- Reducing settlement
For many structures, settlement controls foundation design. Vibratory stone columns stiffen up the soil matrix and reinforce the existing soils to reduce the compressibility of the soils reducing total settlements. Additionally, by installing stone columns, the soil matrix becomes more uniform and reduces differential settlements.
- Mitigating liquefaction
In earthquake-prone areas and regions where the soil is susceptible to seismic induced settlements and liquefaction of granular soils, vibratory stone columns provide a good solution to mitigate these soils. By installing vibro aggregate piers in a grid pattern, engineers can reduce the potential for liquefaction through soil densification.
Applications for Vibratory Stone Columns
In addition to these practical purposes, vibro stone columns are an ideal solution for your projects in the following structures:
- Multi-story buildings
Multi-story structures, office buildings, and skyscrapers place enormous amounts of pressure on the soil. Most surfaces cannot provide enough stability on their own and require additional fortification. Vibro stone columns are often used to increase the bearing capacity and mitigate settlement reduction.
- Commercial centers
For large construction projects covering a significant geographical area, vibro stone columns are used at regular intervals to reinforce the soil and provide additional stability.
- Industrial facilities
When working with previously undeveloped land, vibro stone columns are used to increase the load-bearing capacity for industrial facilities. This is one of the quickest and most efficient ways to increase soil density without using deep foundation systems.
- Liquid storage tanks
By their very nature, liquid storage tanks place a large amount of weight on the surface below. By installing vibro stone columns in the area about these tanks, the soil can remain stable under extreme conditions.
- Grain bins and grain silos
Farmland can be tricky to assess because of its undeveloped nature. When installing grain bins and silos, it’s important to ensure the surrounding soil is properly stabilized. Vibro stone columns are often used to reinforce and strengthen poor soil conditions.
- Grain elevators
Grain elevators play a major role in agricultural farming and economic production in rural areas. When constructing these important facilities, Vibro stone columns are frequently used to increase load-bearing capacity to an adequate level.
- Farm buildings for agricultural machinery
When installing a deep foundation is too expensive or impractical, vibro stone columns allow farm buildings to be constructed over shallow footings, soft soils, and other otherwise unpredictable conditions.
- Wind towers and wind farms
While wind towers themselves aren’t extremely heavy, they are subject to high amounts of lateral force well above the base. As a result, large overturning movement can occur. Vibro stone columns can reinforce the foundation to ensure the increased presence of lateral force doesn’t cause soil displacement or settlement.
Vibro Replacement Process
The installation process for vibro stone columns is simple and streamlined.
First, a vibroflot is driven down into the ground with a device to create a hole. Granular material is then inserted into the device and compacted to create a column in the ground. The compactive device then slowly lifts, and the column continues to be built in lifts as the flot is extracted.
To schedule an installation or to find out more about the installation process as it relates to your specific needs, please contact our team of highly trained engineers and project managers.
Why Helitech Civil Construction Division?
At Helitech Civil Construction, we have provided technical and constructional support to a wide variety of markets and industries since 1987. Using a unique and strategic combination of engineering and construction knowledge, we have effectively positioned ourselves as a leader in geotechnical construction in the Midwest.
While our focus is on quality construction and installation, we pride ourselves on unmatched customer service and engineering support. We believe in helping our clients achieve their goals and find peace of mind.
We find customer service so easy because we truly believe in the quality of our products. Our superior products have proven successful for a number of unique and specialized applications, and we are fully confident in their ability to perform.