Volume three of this text covers soil testing in terms of effective stress, for which the measurement of pore water pressure is the essential feature. The principle and theory of effective stress are explained, practical applications are outlined, and the apparatus used, including its calibration and checking, is described. Most of the test procedures described are those covered by BS 1377, 1990, Parts 6 and 8. Reference is also made to relevant ASTM methods. Routine consolidated-undrained and consolidated-drained triaxal test procedures for determination of effective shear strength parameters are given in detail. Some other related procedures, and tests in the triaxal cell for isotropic consolidation and permeability measurements, are included. The advantages of using the hydraulic consolidation cell (Rowe cell) for one dimensional consolidation is explained, and tests with several arrangements for loading and drainage are described. Measurement of vertical and horizontal permeabilities is also described. The procedures as described make use of manual methods of observation and recording, but reference is made throughout to electronic instrumentation and automatic data-logging facilities. This second edition has been written using the new British Standards. The book gives the procedures commonly used in the geotechnical industry; includes background theory; apparatus; test methods; and applications; and also step-by-step description and explanations, including examples.