A scanning electron microscopy study of natural engineering soil

Rights statement
Awarding institution
  • University of Strathclyde
Date of award
  • 1978
Thesis identifier
  • T3352
Qualification Level
Qualification Name
Department, School or Faculty
  • This thesis forms part of an overall investigation of natural soil fabric being undertaken at Strathclyde University, and is directed towards those fabric features which can only be observed with the aid of a microscope, the soil microfabric. The investigation is split into two main parts. The first is directed towards reviewing previous concepts of the nature of soil microfabric, appraising the available techniques for microfabric study and cataloguing the microfabric observations made on a wide variety of naturally occurring engineering soils. The mode of viewing used is the Scanning Electron Microscope, chosen because of its versatility in terms of its magnification range and ability to accept a wide range of soil textures. The sample preparation method used is the air-drying, fracture, peel and vacuum coat technique but a small comparitive study of the critical point drying technique is also undertaken to investigate the validity of the methods used. The soils investigated represent particular examples of geological groupings and engineering behaviours. In fact, thirty four naturally occurring engineering soils with a wide geographical distribution are studied and a scheme of microfabric characterisation is developed which it is suggested, can suitably describe all the aspects of fabric observed, both solid and pore space, and allow some semi-quantitative assessment to be made. The second part deals with the geological and geotechnical significance of the microfabric observations. By relating these to the known geological histories the genesis of microfabric is investigated and compared to the findings of previous studies. Similarly, by relating the microscopic observations to the known geotechnical properties of the soils, the mechanisms of structural instability in sensitive, collapsing and expansive soils are considered. The investigations, (1) show that many of the previous concepts of the nature of soil microfabric are unrealistic, (2) identify certain factors which play a significant role in microfabric genesis, and (3) place the role played by microfabric in the mechanisms of structural instability into a clearer perspective.
Resource Type
Date Created
  • 1978
Former identifier
  • 490764