Determination of characteristic values for marine clay
Recently, limit state design (LSD) in geotechnical engineering has been developed through LRFD in North America and Eurocode 7 in Europe. LRFD is an approach that estimates resistance by design model and that multiplies resistance factor by calculated resistance to reflect the uncertainty of materials and design models. Whereas, Eurocode 7 employs the partial resistance factor applied directly to each variable in resistance equation that individual soil properties such as cohesion and angle of internal friction are applied. Current methods of estimating characteristic value were discussed with the marine clay of Korea within the framework of characteristic value which has globally argued during the processing of development of Eurocode 7 for geotechnical design. Estimation of characteristic value, an issue of this dispute, affects not only determination of design value applied directly to design of geotechnical structures, but also economic feasibility and stability following results of design. In this paper, the characteristic values for main marine clay were calculated and compared with using some methods proposed. As a result, it was appeared that most of the computed values were close to mean value and less conservative in the order of Student/Ovesen, Schneider and EN 1990. In case of EN 1990 approach, however, it was inappropriate to assess geotechnical design value being calculated less than zero with statistical variability. Also, it was found that current methods have trend of estimating more conservative characteristic values when larger in ground variability.
Geotechnical design to Eurocode 7
The purpose of the Eurocodes is to achieve harmonisation between structural and geotechnical design in Europe. This book demonstrates how the philosophy and principles presented in Eurocode (EC) 7 are applied in practice. The clauses in EC7 are explained with detailed examples and how Cases A, B and C are used in geotechnical designs is described. The most recent developments are outlined, such as the introducation of additional design cases, as EC7 moves towards publication as a full standard. Types of design covered include shallow strip and pad foundations, cantilever and embedded sheet pile retaining walls, slope stability problems, and fills.
Inversion of self-potential anomalies caused by 2D inclined sheets using neural networks
The modular neural network (MNN) inversion method has been used for inversion of self-potential (SP) data anomalies caused by 2D inclined sheets of infinite horizontal extent. The analysed parameters are the depth (h), the half-width (a), the inclination (α), the zero distance from the origin (xo) and the polarization amplitude (k). The MNN inversion has been first tested on a synthetic example and then applied to two field examples from the Surda area of Rakha mines, India, and Kalava fault zone, India. The effect of random noise has been studied, and the technique showed satisfactory results. The inversion results show good agreement with the measured field data compared with other inversion techniques in use.