No description available.

Compressional and shear wave velocity and attenuation measurements were obtained in the laboratory from 50 mm diameter, cylindrical, limestone core samples over a confining pressure range of 5 – 60 MPa. Normal and tangential fracture compliance values, as a function of confining pressure, were calculated for a single fracture cut perpendicular to the long axis of the core. The ratio of the normal to tangential compliance was approximately 0.4 and was independent of the applied stress. Values of normal and tangential fracture compliance calculated were of the order 10^-14 m/Pa, and decreased with an increase in confining pressure. Both Q^-1</sup>_P and Q^-1</sup>_S1/Qs were shown to be small for these samples. A borehole test site was constructed in a Carboniferous limestone quarry, at Tytherington, situated north of Bristol, UK. This quarry was chosen because the rock type was fairly homogeneous and the fractures could be mapped in the quarry walls as well as down three, 40 m vertical boreholes drilled in-line in the quarry floor. Wireline logs were obtained in all the holes and a seismic crosshole survey was carried out between the two outermost boreholes. An estimate of in-situ normal fracture compliance, Z_N, was obtained from the log and crosshole data, in 4 different ways, using effective medium theories as well as the displacement discontinuity theory. An additional estimate of Z_N was obtained from a separate borehole test site constructed in fractured Devonian meta-sediments at Reskajeage, Cornwall, UK. These fractures were much larger in size than those observed at Tytherington quarry. From the above field and laboratory measurements, fracture compliance was shown to increase approximately linearly with the size of the fractures. In addition, a study of crosshole seismic attenuation was performed at Tytherington quarry. Q was found to be frequency dependent. This frequency dependence was interpreted as being due to scattering rather than intrinsic attenuation.

Bibliography: leaves 385-395 / xxv, 395 leaves : ill ; 30 cm. / Title page, contents and abstract only. The complete thesis in print form is available from the University Library. / Thesis (Ph.D.)--University of Adelaide, Dept. of Civil Engineering, 1993

The objective of this thesis was to identify the mechanisms associated with the recurrence of rock-slope instability along the R518 and R523 roads in Limpopo. Advanced geotechnical methods and ASTER imagery were used for the purpose while a predictive rockfall hazard rating matrix chart and rock slope stability charts for unsaturated sensitive clay soil and rock slopes were to be developed. The influence of extreme rainfall on the slope stability of the sensitive clay soil was also evaluated. To achieve the above, field observations, geological mapping, kinematic analysis, and limit equilibrium were performed. The latter involved toppling, transitional and rotational analyses. Numerical simulation was finally resorted to. The following software packages were employed: SWEDGE, SLIDE, RocData, RocFall, DIPS, RocPlane, and Phase 2. The simulation outputs were analyzed in conjunction with ASTER images. The advanced remote sensing data paved the way for landslide susceptibility analysis. From all the above, rockfall hazard prediction charts and slope stability prediction charts were developed. Several factors were also shown by numerical simulation to influence slope instability in the area of study, i.e. sites along the R518 and R523 roads in the Thulamela Municipality. The most important factors are extreme rainfall, steep slopes, geological features and water streams in the region, and improper road construction. Owing to the complexity of the failure mechanisms in the study area, it was concluded that both slope stability prediction charts and rock hazard matrix charts are very useful. They indeed enable one to characterize slope instability in sensitive clay soils as well as rockfall hazards in the study area. It is however recommended that future work is undertaken to explore the use of sophisticated and scientific methods. This is instrumental in the development of predictive tools for rock deformation and displacement in landslide events. / Electrical and Mining Engineering / D. Phil. (Mining Engineering)