The Soil-Rock Boundary: What is it and Where is it?

A major issue in many areas of Civil Engineering practice is the boundary between earth materials that are defined as soil and those that are defined as rock. Designers, contractors, and attorneys are particularly sensitive to this issue. This paper attempts to put major aspects of this problem in perspective. A general framework is presented for describing earth materials in a consistent manner, and examples are given to illustrate the nature of the problem involved.