DCP testing Archives

Dynamic Cone Penetration (DCP) testing is used to measure the strength of in-situ soil and the thickness and location of subsurface soil layers.

Smart DCP Hammer — Smart DCP disc with built-in level.

It is similar to CPT (cone penetration testing) in that a metal cone is advanced into the ground to continuously characterize soil behavior.

In DCP, however, the cone is driven by a standard amount of force from a hammer, and how far the cone moves with each blow is used to determine the soil density and properties at that level.

In DCP testing, the pushing force is applied by manually dropping a single or dual mass weight (called the hammer) from a fixed height onto the push cone unit.

The resulting downward movement is then measured. Unlike CPT systems, basic DCP equipment is hand-portable and may be limited to test depths of 3-4 feet: this makes it a good choice for shallow testing applications such as roadbed construction and maintenance.

Since DCP is essentially hand-powered, it is cheaper and more portable than CPT equipment, but the possibility of human error makes it trickier to obtain consistent and accurate data.

Historically, one of the largest difficulties associated with DCP has been obtaining accurate depth difference measurements with a hand rule after each blow of the hammer.

As you can imagine, taking these measurements by sight and recording them by hand can be slow, finicky work.

Plus, to measure the total depth, the sum of these measurements is calculated, so it is easy to accumulate a troublesome amount of error if each measurement is even slightly off.

Fortunately, handheld electronics technology has alleviated these issues to a great extent. Vertek’s Smart DCP Kit uses a smartphone app and a laser rangefinder to automatically count blows and measure, record, and plot depth.

From the smartphone, this data can be easily graphed in the field and transferred to a computer or client for reporting and analysis.

Automatic data collection saves time, increases accuracy, and means that the test can be efficiently completed by one person. Check out our video below to see how much more efficient the Vertek Smart DCP Kit makes DCP testing.

To further increase the repeatability and efficiency of DCP testing, Vertek offers automatic DCP (ADCP) testing systems. ADCP rigs can be mounted on lightweight trailers, commercially available trucks, or ATVs.

Automated tests are both faster and more consistent than their manual counterparts, and also decrease physical labor for the operator.

DCP and ADCP testing and data analysis is a broad subject, so we’ll return to it in another blog.

In the meantime, be sure to check out the DCP testing information and video demonstrations YouTube channel! You can also download our catalog to see the full specifications and capabilities of Vertek’s Smart DCP and ADCP equipment.

Have questions about whether DCP is right for you?

Click here or give us a call at 1-800-639-6315 to discuss your needs and our solutions.

DCP FAQs

What is a dynamic cone penetrometer?

The Dynamic Cone Penetrometer (DCP) is used to determine underlying soil strength by measuring the device’s penetration into the soil after each hammer blow.

How does a cone penetrometer work?

A cone penetration test rig pushes steel cone into the ground, generally up to 20m below the surface or until the cone reaches a hard layer. The steel cone contains an electronic measuring system that records tip resistance and sleeve friction.

What is DCP testing?

Dynamic Cone Penetration (DCP) testing is used to measure in-situ soil’s strength and the thickness and location of subsurface soil layers. It is similar to CPT in that a metal cone is advanced into the ground to characterize soil behavior continuously.

What is DCP in the construction industry?

Dynamic Cone Penetrometer, or DCP, is a tool used for evaluating the strength of soils on site. It also helps with monitoring the condition of granular layers and subgrade soils in pavement sections over time.

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Assessing the level of compaction of sub-surface soils can be essential to designing and validating compaction, particularly those subject to transient or cycling loads. A perfect example is roadways.

If the soil beneath a roadway is not compacted sufficiently, then over time the cycling loads of passing traffic will compact the soil further, leading to surface failures such as large cracks, potholes, and displaced pavement. Assessing the compaction of non-cohesive soils such as fine sands is a particularly difficult challenge.

As we’ve noted in other blog posts, removing a sample from the ground and sending it to a lab is not only time consuming and expensive, but can be highly inaccurate in non-cohesive soils because the samples by necessity are disturbed from their sub-surface condition.

One alternative to soil extraction is Nuclear Density testing. Nuclear Density testing requires a radiation source such as Cesium or Radium. The instrument emits a beam of particles that either are reflected back or pass through sediments being tested for density. Using a calibrated density gauge can provide results through a variety of different materials, including varied deposition soils or road sub-base.

While Nuclear Density testing is relatively efficient because it uses radioactive materials, operators must be specially trained and licensed. It is also riskier to manage at a worksite.

This is where dynamic cone penetration (DCP) testing comes in. The DCP test gathers simple in-situ soil characteristics that are designed to assess soil density, load bearing capacity and shear strength. Common applications for DCP testing include residential and commercial concrete and foundation leveling, airfield and highway construction, and embankment stabilization.

A manual or automated DCP uses a 60-degree conical tip cone or drive point as the resistive surface. Dual mass DCPs utilize a known weight which is dropped from a consistent height transferring energy through the instrument. The number of blows to penetrate the soil and progressing depth measurements can provide an in-situ density during field testing.

Vertek’s Smart DCP Kit gives users the ability to conduct three times the number of tests compared to standard DCP testing. Dynamic cone penetration can provide a density stratigraphy to beyond 3 feet and is safer and less complicated to administer than Nuclear Density testing.

The adaptive Smart DCP Kit components and free mobile app can display continuous measurement data with each blow (>or<4mm) depth increments as the DCP is driven into the subsurface. Each test’s recorded data is easily saved and shared after each penetration location is completed. Users report that the Smart DCP Kit provides the advantage of identifying a subsurface weakness and the results of the stabilization effort.

While DCP results will be consistent for most soil conditions, it is recommended that the field tests be reviewed in soft sediments to ensure that data interpretation is accurate.

To learn more about DCP testing and Vertek’s DCP products, give us a call at 1-800-639-6315 or contact us today.

What is DCP testing and how does it compare to CPT?