Introduction

Prior to the advent of computer slope stability analyses, it was desirable to express the porewater pressure conditions using a simple single parameter. The development of slope stability charts in particular, such as the ones created by Bishop and Morgenstern (1960), necessitated a pore-water pressure definition. One such approach is to define the pore-water pressure as a function of the overburden stress, which became known as a ratio called R_u.

The purpose of this example is to highlight the use R_u and to offer ways of using R_u so that it better represents the actual field pore-water pressure conditions.