Civil and Building Engineering.

1 Introduction: The following discussion is an introduction to the shear strength of soils, a topic requiring a book to discuss thoroughly. Throughout this discussion, shear strength will be discussed in terms of the Mohr-Coulomb failure criteria: cohesion and friction. Different methods of shear testing are introduced in this discussion. The reader should learn when various shear tests may be unsuitable for characterization of shear strength for an engineering design because the particular design methodology was developed originally using a single, specific form of shear testing.


2 Friction Between Two Surfaces in Contact: This discussion of the mechanics involved in the shear strength of soils begins with fundamental concepts based on Amonton’s law of friction...

3 Direct Shear Testing: A method for testing soils that is similar to the sliding block test is the direct
shear test...

 4 Triaxial Shear Testing: Triaxial shear tests are performed on solid cylindrical specimens of soil...

5 Drained Triaxial Tests on Sand: The changes in stress conditions in a sand specimen during shearing may be understood by plotting the states of stress on a Mohr-Coulomb diagram...

6 Triaxial Shear Testing of Saturated Clays: Triaxial Compression Tests on Normally Consolidated Specimens...

7 The SHANSEP Method: Between the 1950s and 1970s, geotechnical engineers recognized that the
undrained shear strength of many soils followed a characteristic pattern...

8 Other Types of Shear Testing for Soils: Several other types of tests for measuring the shearing properties of soils have been developed in addition to the direct shear and triaxial shear tests...

9 Selection of the Appropriate Testing Method: The foundation engineer must tell the testing laboratory how to test the soil so that the necessary soil properties are measured for the problem at hand...