Understanding the Subsurface with GEOCIVIL’s SCPT

At GEOCIVIL, we are committed to delivering precise geotechnical insights to help engineers, developers, and decision-makers better understand site conditions. Our latest addition to our suite of geotechnical services, Seismic Cone Penetration Testing (SCPT), enhances subsurface investigations by providing critical seismic data alongside traditional CPT results.

What is SCPT?

Seismic Cone Penetration Testing (SCPT) is an advanced geotechnical investigation method that integrates seismic testing with a standard Cone Penetration Test (CPT). In addition to measuring typical CPT parameters such as soil resistance and friction, SCPT directly measures shear wave velocity (Vs) at set depths below the surface.

Why Measure Shear Wave Velocity?

Shear wave velocity plays a crucial role in understanding how a site will respond to seismic activity. The velocity of seismic waves depends on the type and density of subsurface materials: denser materials exhibit higher velocities, while softer materials show lower velocities.

With the introduction of TS1170.5, site-specific Vs measurements to a depth of 30 metres are now a key component of site classification. This means that measuring Vs is no longer just a valuable option—it is an essential requirement for seismic site assessments.

How Does SCPT Work?

GEOCIVIL’s specialist Geomil cone is inserted into the ground to assess soil resistance and friction. At set intervals, typically every metre, seismic waves are generated at the surface using a sledgehammer strike on a horizontal beam. Sensors in the SCPT cone detect the wave signals and calculate the shear wave velocity of the soil.

Unlike conventional SCPT cones that require separate tests for CPT and seismic wave velocity, GEOCIVIL’s innovative SCPT system integrates both tests into a single efficient process. This approach significantly reduces testing time and costs while delivering comprehensive data for site assessments.

Key Benefits of SCPT with GEOCIVIL

  • Liquefaction Analysis: Identifies the presence, thickness, and seismic characteristics of liquefiable layers.
  • Seismic Site Classification (Vs30): Accurately determines Vs values to comply with the new TS 1170.5 classification requirements.
  • Efficiency: Combines CPT and seismic testing in one streamlined process, reducing overall project costs and timelines.
  • Comprehensive Subsurface Data: Provides both mechanical and dynamic soil properties for a detailed understanding of site conditions.
  • Tailored Solutions: SCPT services are adapted to meet the specific needs of each project, ensuring high-quality, reliable data.

What to Expect from an SCPT Report

Our expert geotechnical team processes and analyses SCPT data to provide clear, accessible insights. Even for those without a technical background, our reports clearly present the following:

  • Detailed subsurface layering and material properties
  • Shear wave velocity values for each layer
  • Subsurface variations across the site
  • Integrated seismic and CPT results for a holistic understanding of site conditions

SCPT is a game-changer in modern geotechnical investigations, offering precise, efficient, and cost-effective solutions for seismic site classification and ground behaviour analysis. Contact GEOCIVIL today to learn how our SCPT services can support your next project!

Figure 1: Field set-up used for SCPT data acquisition with a double receiver shown. S1 and S2 represent the straight-line travel path from the source to the receivers at the different depths Z1 and Z2. Figure 2: SCPT and CPT data comparison highlighting the relationship between the seismic velocity to change in subsurface material.