A visitor from Southern California

On August 17, 2010, in Discussion, by Ian Brown

We enjoyed a visit today from Professor Man-chu Ronald Yeung.   I first met Ron while he was a graduate student at University of California, Berkeley where he was completing his PhD research with Professor Richard Goodman.   Our paths keep crossing in the United States, and New Zealand where his wife’s family live. Ron has had [...]

When a small rock fall causes traffic chaos

On August 8, 2010, in Discussion, by Ian Brown

Earlier today, a small rock fall occurred on the slope adjacent to State Highway 2 between Wellington and Lower Hutt.  I know about this because shortly after the rocks hit the highway, I was in a serious traffic jam.   Instead of the expected 15 minute drive to the golf course, I endured a three hour [...]

Empirical estimation of rock slope stability

On August 6, 2010, in Discussion, by Ian Brown

A colleague contacted me today to see if I had a copy of a paper published in New Zealand Engineering in 1964.   At the time of publication, I was a high school student, but the paper did come to my attention a few years later when I started my professional career.   The author, Tom Grant-Taylor, [...]

44th US Rock Mechanics Symposium

On June 30, 2010, in Discussion, by Ian Brown

I have been attending the 44th US Rock Mechanics Symposium held in Salt Lake City, Utah (from June 27 to 30th). I am a member of the sponsoring organisation, (ARMA – the American Rock Mechanics Association) and have enjoyed these meetings on an irregular basis since the 19th Symposium (1978), held at Stateline, Nevada. This [...]

Some useful advice …

On June 2, 2010, in Discussion, by Ian Brown

I have recently been reviewing TSLOPE documentation, and came across the TSLOPE/TSTAB Users’ Manual dated 1984.    It is a while since I had opened this manual, and was reminded that it contains some very useful advice. The preface, as written by Robert Pyke, should be required reading for all engineers.  We do need reminding from [...]

The failure of Aznalcollar dam

On May 11, 2010, in Discussion, by Ian Brown

On May 11, 2010, Professor Antonio Gens from the Technical University of Catalonia in Barcelona gave a very interesting presentation to members of the Wellington branch of the New Zealand Geotechnical Society Inc. On April 25, 1998,  the tailings dam at the Los Frailes lead-zinc mine at Aznalcóllar near Seville, Spain, failed and released 4-5 [...]

Limit analysis and stability charts for 3D slope failures

On April 15, 2010, in Discussion, by Ian Brown

We have just received the latest issue of the Journal of Geotechnical and Geoenvironmental Engineering (ASCE).  On page 583 there is an interesting paper titled  “Limit analysis and stability charts for 3D slope failures” authored by Radoslaw Michalowski of University of Michigan. In the introduction to his paper, Professor Michalowski states that no convenient methods [...]

Selection of seismic coefficients for use in pseudo-static slope stability analyses

On March 8, 2010, in Discussion, by Robert Pyke

Analyses of seismic slope stability problems using limit equilibrium methods in which the inertia forces due to earthquake shaking are represented by a constant horizontal force (equal to the weight of the potential sliding mass multiplied by a coefficient) are commonly referred to as pseudo-static analyses. They are relatively simple to perform but involve many [...]

Back analysis of slope failure

On February 12, 2010, in Discussion, by Ian Brown

We are always looking for well documented slope failures that show the three dimensional nature of the failure.   The photograph below is of a slope failure in weathered sandstone that could have provided such an example.

Mangorewa Gorge

On January 5, 2010, in Discussion, by Ian Brown

On a recent road trip between Tauranga and Rotorua, I drove through roadworks on state highway 36 (part of the New Zealand national roading network).   I was most impressed by the rock stabilisation work that has been carried out.  However the construction was not without some challenges, particularly to motorists who were using the [...]