Professor and Head, University of Manitoba, Winnipeg, Manitoba
Geotechnical engineer, West Vancouver, British Columbia
Pages: 9 Published: Jan 1981
Geotechnical engineers are familiar with the role that time plays in the stability of the sides of an excavation. The sides of trenches dug through silts and fine sands are often observed to stand vertically for perhaps 10 or 15 min, then start to fail; railroad cuts through London clay started to fail after 60 years. The time to failure is a function of both the permeability and the volume change characteristics of the soil or rock which is involved.
In open pit mining, the time to failure is of utmost importance, yet it is only now that theoretical tools are available which enable the engineer to design slopes for both economy and safety. This recent theoretical work points out the need for the pore pressure response of the soil or rock to be measured during strength testing. The need and the test requirements are the subject of this article.
mining, pit slopes, shear strength, pore pressure, dilatancy, consolidation
Paper ID: STP28774S