THE PREPARATION OF CLAY SOILS FOR DETERMINATION OF STRUCTURE

Abstract

Summary Most methods for the determination of structure require the soil to be freed of water and yet to retain its original character. The methods of freeze‐drying and critical point‐drying are examined and it is concluded that they are not generally satisfactory. It is possible to preserve the soil fabric whilst water is slowly exchanged with an organic solvent (e.g. methanol or dioxan). The fabric is hardened and the degree of hardening is increased by subsequent exchange with certain water‐immiscible solvents (e.g. diethyl ether). Some shrinkage must be tolerated when it is desired to remove the liquid from the fabric. The best method was found to be infiltration by liquid carbon dioxide and its removal above its critical temperature. Despite some shrinkage the fabric seems unchanged.