This guideline provides a standardised and consistent framework for the field classification and description of soil and rock for engineering purposes. It has been used extensively in New Zealand since its publication. It provides a method of soil and rock description that reduces the subjective nature and variability of descriptions of materials encountered during the investigation, design, and construction of an engineering project. As such, the method is designed principally for use in the field where materials are described, and descriptions are recorded on logs. It provides a methodology for the description of materials such that:

•All significant observable properties of soil and rock are described;

•Descriptions of a material consistently use the same terms; and

•Particular properties or groups of properties appear in the same relative position within any description, so that the user may rapidly locate them.