QAQC in Construction

Soil types The type of soil determines the strength and stability of trench walls. Identifying soil types requires knowledge, skill, and experience. Even hard soil may contain faults in seams or layers that make it unstable when excavated. The foreman or supervisor must be knowledgeable about soil types found on a project and plan protection accordingly. This knowledge must include an awareness that soil types and conditions can change over very short distances. It is not unusual for soil to change completely within 50 metres or for soil to become saturated with moisture over even smaller distances. The Construction Regulation sets out four soil types. If you are unsure about the soil type, have the soil tested to confirm the type. Type 1 — It is hard to drive a pick into Type 1 soil. Hence, it is often described as “hard ground to dig”. In fact, the material is so hard, it is close to rock. When excavated, the sides of the excavation appear smooth and shiny. The sides will remain...