2. Suction control and measurement techniques

2.1 Introduction

Suction is a difficult physical quantity to measure, and various approaches are needed to cover the full range of suctions encountered in soils, which can reach several hundred megapascals. This technical difficulty is probably one of the reasons for the lack of experimental data on the behavior of unsaturated soils, both in mechanical terms and in terms of water and air transfer. However, Croney et al. [12] were quick to provide a comprehensive description of most techniques for monitoring and measuring suction in soils. Many techniques rely on the use of porous ceramic stones with very fine porosity, which can only be desaturated under suctions much higher than those applied to soils: these stones therefore...