How should soil and rock deposits be classified?

Soil and rock deposits should be classified by a competent person using visual and manual analysis because this approach ensures a comprehensive understanding of the material's characteristics. A competent person possesses the necessary training and experience to assess various aspects of the soil and rock, including texture, color, composition, and moisture content, which are critical for determining engineering properties and potential behaviors of the material.

Visual and manual analysis allows for the identification of features such as grain size, layering, and compaction that could significantly influence excavation and construction processes. This method also allows for the assessment of consistency and strength, which are vital for ensuring the safety and integrity of excavations and structures.

Relying solely on visual inspection lacks the depth of analysis needed, as it may overlook important nuances in the material properties. Similarly, classification by unskilled individuals can lead to misinterpretations and unsafe decisions. Automated testing, while useful, cannot always provide the nuanced insights that a trained professional can gather through tactile and visual methods. Thus, the combination of skilled observation and manual assessment repeatedly proves to be the most reliable method for classifying soil and rock deposits.