Methods In Geotechnical Engineering Research Articles

Probabilistic Methods in Geotechnical Engineering

Probabilistic Methods in Geotechnical Engineering

Interview with ITA President Z. Eisenstein

Dr. Zdenek (Dan) Eisenstein has been involved in tunnelling for nearly thirty years. He received his undergraduate and doctoral degrees in civil engineering and geo-technical engineering, respectively, from Czech Technical University, Prague. Since 1969, he has been a professor of civil engineering at the University of Alberta in Edmonton, Canada. His research has been oriented toward design and analysis of undeground structures; deep excavations; soil structure interaction problems; and application of numerical methods in geotechnical engineering. He has develop graduate and professional courses in solid mechanics, foundation engineering, tunnelling, light rail transit, and numerical modelling. Prof. Eisenstein has served as a consultant on several hundred projects throughout the world involving dams, foundations, deep excavations, and tunnels. For the Channel Tunnel project, he was engaged to evaluate the compatibility of the tunnel systems with the ground. A member of the Canadian Geotechnical Society and the advisory board of the International Journal for Numerical Methods in Geomechanics, Prof. Eisenstein served as Editor of Canadian Tunnelling from 1985 to 1989. He has lectured extensively on a wide range of topics related to tunnelling, and has published more than 100 papers in journals and conference proceedings. Prof. Eisenstein has served on the Executive Council of the International Tunnelling Association since 1987; he was elected ITA First Vice-President in 1989 and President in 1991. Midway through his presidency, Prof. Eisenstein talked with Tunnelling and Underground Space Technology about the ITA's accomplishments over the past year-and-a half, and his goals for the remainder of his term of office.

Partial and total factors of safety in anchored sheet pile design: Discussion

Valsangkar and Schriver have contributed to furthering the use of limit state design methods in geotechnical engineering. The title of the paper implies partial safety factors for anchored bulkhead design, but the only limit state that was examined was kickout. Design of the bulkhead requires examination of a number of other limit states including anchor rod capacity, sheet pile yield, wale yield, and anchorage capacity (Navfac 1986), and all of these use soil and water pressures in their formulation. It would be desirable to use, for example, the same resistance factor for the soil friction angle for each limit case. To establish the adequacy of the recommended partial safety factors, the other limit states for an anchored bulkhead should also be compared with conventional design. An interesting outcome of this paper is that with the proposed partial safety factors for limit state design, the sequence of solving of statics problem, i.e., how water pressures are introduced into the moment equation, affects the design. The authors recommend that commentary be included in the Canadian Foundation Engineering Manual (Canadian Geotechnical Society 1985) to clarify this point. The partial safety factors discussed by the authors are applied to the loads and resistances in the design and are used to account for uncertainties in these values. However, implicit in these factors are components that account for uncertainties in the dimensions and method of analyses used. Water has no shear strength and virtually no variability of unit weight. The quantity that causes variability in the water pressures is the water level difference, i.e., a dimension. In some cases, such as this water level difference, should a separate factor be considered that would be applied directly to the dimension before being used in the limit state equation? If applied in this case, the sequence of incorporating water pressures in the moment equation would not change the design. For anchored bulkheads in particular, another dimension that should be considered for a separate factor is the dredge depth in front of the bulkhead. Dredging, which often occurs on a regular basis during the life of a bulkhead, may give a higher variability to the passive pressure than would normally be experienced with passive pressure being used in other types of design. Terzaghi (1954), Tschebotarioff (1973), and Navfac (1986), among others, recommend an increase in the embedment depth to account for this. Since this type of partial safety factor is thus used by many in conventional design, more widespread use of a partial safety factor applied to dimensions in limit state design should perhaps be considered.

Delineating concealed faults and shallow subsurface geology along the Wasatch Front, Utah, USA, by integrating geophysical and trench data

Abstract Planning and development along the Wasatch front must compensate for the geological hazards associated with faulting. Studies show that future ruptures will probably occur along already existing zones of weakness. Although any surface faults can be detected by surficial geological mapping others have no visible expression and can only be located by subsurface investigations. Geophysical methods, such as seismic refraction, gravity, magnetic, and radar can be integrated with geotechnical engineering methods such as drilling and trenching to obtain a better understanding of the subsurface geology at a specific site. Seismic refraction, gravity and magnetic surveys conducted near Provo, Utah along the Wasatch Mountain front have helped delineate shallow, concealed faulting. The reduced, modelled gravity and magnetic data typically correlate well with the refraction depth sections generated using the General Reciprocal Method (GRM). Field observations coupled with the geophysical data facilitated the identification of a number of probable faults along Rock Canyon Road, allowing an estimate to be made of the magnitude and direction of throw on the fault. A normal fault associated with a prominent north–south scarp near Rock Canyon Road was chosen for a case study. This fault scarp was later trenched by the Utah Geological and Mineral Survey (UGMS) and provided a direct comparison with the geophysical data sets. As all the data sets at this site correlate well with the subsurface geology, confidence is increased in interpreting other parts of the line. The characteristics of subsurface deformation can be used to gain a better understanding of the potential for surface rupture at a site and thereby in planning and site development and in devising remedial measures to mitigate the effects of earthquakes in populated areas.

Numerical methods in geotechnical engineering. Edited by C. S. Desai and J. T. Christian. McGraw‐Hill Book Company, 1977. No. of Pages: 783.

Numerical methods in geotechnical engineering. Edited by C. S. Desai and J. T. Christian. McGraw‐Hill Book Company, 1977. No. of Pages: 783.

Numerical methods in geotechnical engineering : Desai, C S; Christian, J T (editors) New York: McGraw-Hill, 1977, 783P

Numerical methods in geotechnical engineering : Desai, C S; Christian, J T (editors) New York: McGraw-Hill, 1977, 783P