Abstract
The short term stability condition of cuts in clay and embankments on clay is generally assessed on the basis of measurements of undrained shear strength. The strength which can be mobilised in the field is often significantly different from that which is determined by standard testing procedures. Three factors which are known to have considerable influence on undrained shear strength measurements are: (a) rate of loading (b) orientation of the failure surface (c) type of shear test employed. An investigation has been made into the influence of these three factors on the undrained shear strength of a soft silty clay from King's Lynn, Norfolk, and the results are presented in this thesis. It has been found that the undrained shear strength (a) decreases with increasing time to failure by about 4% for each log cycle of time. (b) is relatively insensitive to orientation of the failure surface. (c) is a function of the type of shear test employed. For example, strengths in triaxial extension are about 60% of strengths in triaxial compression, which, in turn, are about 60% of strengths obtained from direct shear box tests.