CSL principle and configuration
Cross-Hole Sonic Logging uses ultrasonic paths between access tubes embedded in the pile. One probe transmits and another receives; depth and tube-pair identifiers locate each measurement.
Measurements across different pairs allow comparisons between paths. Unlike PIT reflections from the pile head, CSL examines transmission through material between probes rather than an echo returning from the toe.
Before acquisition
Consider tube provision during construction planning. Establish their arrangement, identifiers, continuity and access, checking the coupling conditions required by the chosen configuration.
Obstructions, inadequate coupling or tube problems may compromise signals. Preparation is therefore more than having an instrument available and must be recorded with test conditions.
Information and anomalies
Compare first-arrival times and signal characteristics by depth and tube pair. A delay or loss of signal can identify an interval for review but cannot determine its cause alone.
Check anomalies against path geometry, tube conditions and casting records. CSL can be appropriate when the question concerns concrete quality along accessible, pre-installed paths.
Limitations and reporting
Coverage concerns the concrete crossed by the paths; material outside the tube network is not automatically assessed. Overall length and load-bearing capacity are not universal CSL outputs.
Associate records with tube pairs and depths, distinguish consistent intervals, anomalies and unassessable acquisitions, and justify further investigations. No unverified acceptance thresholds or standards are prescribed.
Related guides
Frequently asked questions
- Do integrity tests measure load-bearing capacity?
- No. They assess aspects of integrity or pile response within method limitations; they do not replace a load-capacity assessment.
- Which method is always best?
- None: the objective, access and pile conditions determine what information can be obtained.
- Is estimated length certain?
- No: it depends on velocity assumptions, identifying the response and boundary conditions.
References and documentary scope
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