Rise of Tomography: How CHUM 2D/3D Imaging Improves CSL Tests

In today’s advanced infrastructure landscape, deep foundations are non-negotiable. From high-rise buildings to massive bridges, the integrity of bored and cast-in-place concrete piles has a direct impact on the safety and longevity of a structure. That’s why Crosshole Sonic Logging (CSL) tests have become an essential quality control tool for foundation engineers.

But CSL technology has evolved. No longer limited to basic waveform readings or signal loss graphs, it now includes 2D and 3D tomography, giving engineers a detailed internal "scan" of pile defects. And at the forefront of this evolution is Piletest’s CHUM system.

What is Pile Tomography in CSL Testing?

Pile tomography refers to the creation of visual cross-sectional or volumetric images of the inside of a concrete pile, using ultrasonic signal data gathered during CSL testing. Instead of interpreting vague signal drops, engineers now have access to:

• 2D vertical slices showing changes in concrete quality

• 3D full-body models that highlight the location, size, and severity of defects (see below)

This helps engineers make faster and more accurate decisions about pile acceptability or necessary remediation.

CHUM System: A Technical Overview

Piletest’s CHUM (Crosshole Ultrasonic Monitor) is designed specifically for CSL testing using ultrasonic pulse transmission between access tubes installed in piles. Here’s what sets it apart:

• Supports both 2D as standard and 3D tomography (optional)

• Compatible with plastic and steel (recommended) tubes

• Modular system (can start small and scale)

• Automated data collection & waveform analysis

• Real-time visualizations

With its advanced software and portable design, CHUM simplifies data collection even on complex job sites. Discover more about their innovative solutions here.

How CHUM’s 2D & 3D Tomography Improves Testing

Enhanced Defect Mapping

Traditional CSL outputs show travel time (FAT) and signal energy (RE) across tube pairs. CHUM’s tomography processes these readings into clear color maps, helping identify:

• Voids and the ability to assess their volume and location

• Honeycombing

• Inclusions

• Cracks

In 2D, these show up as horizontal or vertical “slices” of the pile. In 3D, you can rotate, zoom, and isolate areas of concern, making it easier to communicate findings to clients, contractors, and regulatory bodies. (as can be seen above)

Reliable Visual Interpretation

Tomography minimizes human error in interpreting raw data. Instead of deciphering graphs, engineers can view intuitive visuals. This is especially useful for:

• Teams with varying experience levels

• Government reports or audit submissions

• Stakeholder presentations

The result? Greater clarity, fewer disputes, and stronger documentation for pile quality.

Real-Time Feedback

With CHUM’s software, imaging happens on the spot. Engineers no longer have to wait hours or days for post-processing. If a defect appears during scanning, the testing team can:

• Retest the area with the flaw immediately in 2D

• Transfer the raw data to the 3D Tomography engine to create 3D Tomography

• Watch on site with the complementary 3D viewer of the CHUM standard software

• Add more profiles to the assessment if needed

• Alert project managers right away

This speed prevents costly rework and helps maintain timelines.

Project Adaptability

CHUM’s tomography is especially valuable on projects with:

• Large-diameter piles

• Critical load-bearing requirements

• Unique site conditions (e.g., marine, seismic)

• Whenever the CHUM CSL system detects a flaw in the pile

In regulated infrastructure projects where detailed QA documentation is mandatory, 3D tomography can become a project requirement for compliance.

Because 3D tomography can assess the volume of a defect in a large pile, engineers can evaluate if the defect is dangerous for the pile. Then, they can decide if a fix is needed and how to implement it to address the defect. For large piles, this can mean saving the pile and saving a significant amount of money.

How It Works: The CHUM Tomography Process

Here's a simplified version of the tomography workflow using CHUM:

1. Install Access Tubes: Minimum of 2 tubes for CSL, more for tomography (typically 4+).

2. Data Collection: A transmitter and receiver probe are lowered into pairs of tubes.

3. Pulse Generation: An ultrasonic signal is sent and received across the pile.

4. Data Logging: First Arrival Time (FAT) and Relative Energy (RE) for each profile (i.e, between any two access tubes). Readings are recorded across multiple depths and angles if tomography is required.

5. Software Analysis: CHUM’s proprietary software compiles the readings into 2D and 3D maps.

6. Output Generation: Reports and images are generated in 2D and 3D formats using the CHUM complementary 3D viewer, and delivered as suitable for clients or regulatory submission

   
   

Key Features of CHUM Software

• Live Imaging: View data and tomography in real-time

• Automated Pairing: For quick data collection across multiple tube pairs

• User Feedback Tools: Built-in case analysis, past test libraries

• Multi-Language Interface: Useful for international teams

• Built-in data share functionality

• Customizable Reports: Easily exported in various formats

  
  

Real-World Feedback from Field Engineers

Structural engineers and QA professionals using CHUM consistently highlight its:

• Accuracy: Pinpoints even subtle changes in concrete quality

• Ease of use: Minimal training required, clear visuals

• Time savings: Faster and efficient testing and reporting, and fewer retests

• Client trust: Visual evidence builds confidence

CHUM vs Other CSL Systems

Compared to conventional CSL tools, CHUM with tomography offers:

• Higher resolution defect detection (Highest sensitivity on the market)

• Visual clarity instead of waveform guesswork (Supports DFI flaw criteria with a color-coded bar per profile, in real time)

• Better documentation for third-party verification

• Reduced risk of false positives/negatives

• Full support for True 3D visual output

These enhancements make CHUM ideal for projects with tight QA requirements, such as government buildings, hospitals, airports, and critical load-bearing foundations.

What About Equipment Investment?

While tomography-capable systems like CHUM involve a slightly higher upfront cost, the return on investment is fast:

• Avoiding one major pile rework can pay for the system

• Reduced engineer interpretation time lowers labor costs

• Project delays and disputes are minimized

• Piletest Second Opinion Support (SOS) service helps mitigate marginal cases

CHUM also includes a 3-year Warranty and free software updates for 10 years, ensuring your investment stays current.

Where the Future Is Headed

The next generation of CSL and tomography tools will likely focus on:

• AI-enhanced interpretation

• Remote diagnostics and cloud integration

• Smaller, lighter hardware

• AR overlays for in-field augmented visualization

CHUM already leads in this direction by offering a field-ready, touchscreen-based workflow and a track record of continuous product development.

Final Thoughts

For structural engineers and QA specialists involved in deep foundation projects, the CHUM system’s pile tomography is more than just an enhancement—it’s a leap forward to a more precise, efficient, and professional standard in CSL testing.

With cutting-edge 2D and 3D imaging capabilities, it uncovers imperfections that standard tests might overlook, streamlines the interpretation of complex waveforms, and enables you to deliver your findings with clarity and assurance.

In high-pressure construction scenarios, this level of detail can be crucial in preventing costly errors and ensuring project success. Explore how the CHUM system is setting new benchmarks in imaging technology by visiting this page.

Frequently asked questions

What is pile tomography in CSL testing?

It’s the use of ultrasonic data to generate 2D or 3D images of a pile’s internal flaws and defects.

What advantages does CHUM tomography offer?

It provides real-time visuals, improved defect detection, location and volume, and easier interpretation.

Can CHUM work with plastic tubes?

Yes, CHUM supports both steel (recommended) and plastic access tubes.

Is training required to use CHUM software?

Minimal training is needed. The software is intuitive and offers real-time guidance.

How many tubes are needed for 3D tomography?

At least 4 access tubes are recommended for effective 3D reconstruction.