Split Spoon Sampler: How it Works in Soil Sampling

A split-spoon sampler lets you extract undisturbed soil samples from the subsurface to measure the load-bearing capability of the soil of your potential construction site so you can design stable and safe structures.

Soil sampling is the process of extracting a small volume of soil for analysis. Such tests reveal specific characteristics of the soil to help you design stable and durable structures.

Interlocking split-spoon sampling is one of these important soil sampling and testing procedures. What is split spoon soil sampling, and how does split spoon work?

This article will answer these questions. At the end of the article, you’ll be one step closer to determining that the ground can support the intensity and length of your structure’s load, ensuring stable and durable structures.

What is a Split Spoon Sampler for Interlocking Soil Sampling?

Interlocking split spoon sampling measures the load-bearing ability of the subsurface. This ensures it can support the load placed on it.

We currently build on the ground, not in the air. Every type of soil has a specific load-bearing capacity per unit area. If your structure’s load exceeds this capacity, the soil will fail, causing the structure to sink or collapse.

Therefore, ensure the soil can support the load without settling or failing. Split spoon sampling technology helps with this.

In sandy or loose soils, hollow stem augers collect samples and prevent contamination. They come in various diameters and internal dimensions.

It involves extracting a volume of soil from the sub-surface and testing the soil to determine its load-bearing capacity.

Also read: Sand Equivalent Test: What Can You Learn.

Components of Split Spoon Sampler

A split-spoon sampler lets soil scientists and geotechnical engineers collect soil samples from below the surface. This device preserves the sample’s integrity for analysis, helping determine the ground’s bearing capacity.

• Interlocking split spoon barrel/ tube. Serves as the main body of the sampler. It is driven into the ground to extract samples. This steel tube is split into two equal halves. When locked together, they form a hollow space for the sample during drilling. After drilling, you slit them open to retrieve the soil.
• Drive shoe. The drive shoe threads onto the lower end of the split barrel. It holds the two tube halves tightly together. The drive shoe cuts into the ground and directs the sample into the tube.
• Interlocking split spoon head. The interlocking split spoon head threads onto the upper end of the split barrel. It also holds the two tube halves together. Unscrewing the head splits open the barrel to access the soil sample after retrieval.
• Lifting head. The lifting head attaches to the top of the split spoon head. It allows the attachment of lifting equipment to hoist the sampler out of the ground.
• Liner tubes. Fit into the split tube to protect the soil sample from contamination during retrieval. The sample enters the liner tubes directly when the interlocking split spoon sampler penetrates the soil. So, when you split the tube to retrieve the collected soil, it remains undisturbed in the liner tube.

How Interlocking Split Spoon Sampling Works

A standard interlocking it has a steel tube body that splits into tube halves tightly engaged, a split spoon head threaded onto the upper end of the body and a drive threaded onto the lower end of the body. The main components of the interlocking split spoon sampler are:

An interlocking split spoon sampling operation is easy to understand. It involves using a falling weight or hammer to drive a split spoon tooling into a hole in the ground and noting how many blows it takes to drive the tooling to a specific depth.

In some cases, hollow stem augers are used to drill the hole and collect samples, especially in sandy or loose soils, to prevent contamination.

The number of blows indicates how compacted the soil is, helping you calculate the load-bearing capability of the sandy subsurface so you can design a safe structure.

Specific Steps for Interlocking:

• Drill a hole to the desired depth using a soil auger.
• Place a tripod above the borehole.
  Attach the interlocking split spoon sampler to the bottom of a guide rod (drill rod).
• Add a 63.5kg (140 lbs) hammer and an anvil to the guide rod.
• Mark a point 75cm (30 inches) above the anvil. Release the hammer from this height for a consistent drop.
• Position a centric guide over the borehole and place the guide rod setup through it.
• Put a pulley at the top of the tripod and suspend a rope over it. Attach the hammer to one end of the rope with a hook.
• Make four markings along the guide rod at intervals of 15 cm (6 inches) from the ground surface.
• Drop the hammer from the marked point above the anvil, letting it fall freely and strike the anvil to drive the tooling into the soil.
• Continue dropping the hammer until the tooling penetrates the first 15cm (6 inches). This is the seating drive, so you don’t need to count the blows.
• Count the blows needed to penetrate the second and third 15cm. Record how many blows drive the tooling from 15 to 30 cm and from 30 to 45 cm.

The standard penetration test (SPT) N-Value is the number of blows required for 30cm penetration after the seating drive is removed. You can then use this to determine the bearing capacity of the soil.

Are Interlocking Split Spoon Soil Samples Disturbed?

The standard interlocking is the most commonly used sampler for obtaining undisturbed soil core samples from the subsurface.

As the interlocking split spoon sampler penetrates the soil, the drive shoe cuts the soil and pushes it into the tube, ensuring the split spoon sample is undisturbed.

Where Interlocking Split Spoon Sampler Can Be Used

An interlocking split spoon sampler is used when a construction or major structural modification project is being considered.

You test the undisturbed soil removed from the two interlocking split spoon samplers, to know the bearing capacity of the soil, then use the information to design a stable and safe structure.

An interlocking it is the industry standard for extracting undisturbed soil samples from various depths of the subsurface for testing for geotechnical and construction projects. It is also used in environmental projects for collecting samples.

In fact, before sonic technology became popular, split spoon sampling was how core samples were collected. It’s still in use for this purpose when drill rigs can reach the depths required.

Who Can Perform Interlocking  Split Spoon Sampling?

The interlocking split spoon sampling operation is relatively easy, so you may be able to do it on your own. However, getting a professional drilling tooling company to do split spoon sampling for you is advisable.

Professionals can perform your split spoon sampling better, faster, and safer than you can.

Advantages

The advantages of split spoon sampling are as follows:

• Reliable. Interlocking split spoon sampling is a standardized procedure, meaning it is a reliable method of assessing soil properties.
• Versatility. It can be used to collect samples from different soil types, including gravel, sand, silt, and clay. This makes it applicable in several geotechnical investigations.
• Depth profiling. It can be used to collect samples at various depths. This helps you understand variations in soil properties at different depths.
• Comparative analysis. You can use the information obtained from the split spoon sampler (SPT N-value) to compare soil properties and geotechnical conditions at different sites. This helps in site selection.
• Safe. Unlike other invasive drilling methods, It minimizes disturbance to the soil, making it a relatively safer option in some situations.
• Cost-effective. Because of the simplicity of split spoon sampling, it is relatively economical when compared to other geotechnical tests.
• Why should you choose split spoon sampling?

Split spoon sampler is the industry standard for measuring the load-bearing capability of samples of the soil of a potential construction site.

Before any geotechnical or infrastructure project, you need to measure the bearing capacity of the soil of your potential construction site to help you design stable and safe structures. However, there is no alternative to a split spoon sampler to do this.

You may also choose interlocking split spoon tooling or interlocking split sheath if you need core samples for environmental sampling purposes but do not want to use sonic drilling technology.

Takeaway: Know the Bearing Capacity of the Soil of your Potential Sign and Design Table and Safe Structures

Choose split spoon sampling, split spoon tooling, or interlocking split sheath to measure the load-bearing capacity of the soil.

Every soil has its own load-bearing capability. If the load of the structure you’ll place on the ground is more than the bearing capacity of the soil, the soil will give way, and your structure will sink or collapse.

So, interlocking soil samplers are perfect for measuring the bearing capacity of soil to help you design stable and safe structures.

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