TABLE OF CONTENTS Since there is such a wide variety of soil types, it is necessary to describe and classify soils in terms which convey their characteristics clearly and concisely, and which are generally accepted and understood by geotechnical engineers and researchers. Bjerrum 1973 classify soft clays based on their engineering geological history and emphasising the change in properties which have occurred since their deposition as normally consolidated young clays, normally consolidated aged clays, overconsolidated clays, weathered clays in upper crust, quick clay deposits and cemented clays. In this book, however, the term "soft soil" is defined as clay or silty clay soil which is geologically young, and come to an equilibrium under its own weight but has not undergone significant secondary or delayed consolidation since its formation. It is characterised by the fact that it is just capable of carrying the overburden weight of the soil, and any additional load will result in relatively large deformation. Soils which have not completed the consolidation under their own weight are also included in this group.
The study of soil behaviour may be approached in four main characteristic groups; index properties, compression properties, strength properties and deformation properties under deviatoric loading condition. In the following sections these four main characteristic groups will be discussed.
The determination of soil properties of soft soils requires undisturbed samples of high quality. The quality of the samples depends on the sampling, storage and preparation techniques. All the apparatus so far developed for sampling from the...
