We have experience and understanding extending beyond the basis of good geotechnical mapping.
Geotechnical Mapping – Geotechnical mapping, while sometimes included as part of preliminary site investigations where rock exposure permits, is more commonly undertaken once a project is in production and the rock mass is exposed. In both cases, mapping provides a broader view of the rock mass than diamond drilling alone. Persistence and spacing of discontinuities, as well as the relationships between fracture sets, are difficult or impossible to see in drill core, but can usually be relatively easily seen, and mapped, in outcrops. Therefore, incorporating mapping data in the geotechnical rock mass model reduces the uncertainty that exists when only drilling data is available.
As with geotechnical core logging, mapping of geotechnical parameters is a detailed process that requires focused attention by a competent practitioner if reliable, high-confidence data is to be generated.
With specific reference to producing operations, geotechnical mapping can (and should) be expanded beyond geology and rock mass quality information and may also include ground behaviour, support performance, zones of water inflow, etc. Thorough documentation of rock mass conditions and ground reaction allows for the verification of design assumptions. The level of detail required depends on the complexity of the site and the accuracy of the existing geotechnical rock mass model. Site-specific model calibration can allow for further refinement of the site rock mass model, increasing confidence in predictions of expected ground behaviour.
Accurate geotechnical ground models provide excellent opportunities for design optimizations using actual ground conditions and ground responses as observed in situ (for example, “field fitting” of empirical design methods, and calibration of numerical stress models). Greater accuracy and higher confidence based on site-specific observations can justify the utilization of lower factors of safety (as uncertainty is reduced), resulting in reduced operational costs without compromising safety.
At MDEng, we have experience and understanding extending beyond the basis of good geotechnical mapping. Our personnel have knowledge of how different components of the rock mass and support systems interact, as well as understanding of predictive models so that time in the field can be optimized either collecting relevant data ourselves or training site personnel in relevant techniques.