5.6
LRFD Slope Stability
5.6.1 Introduction
In my opinion slopes are the most difficult topic in geotechnical engineering. Why? Because slopes are highly statically indeterminate.
You may ask, “What does that mean? Structural professors talk about statically indeterminate structures, in fact, I recall having a college class by that name. But what in the world is a statically indeterminate slope?”
OK, I'm going to have to work a bit to give you a better explanation. Of course I could give you the excuse that the topic of slope stability is extensive and is covered by several thick books! But then I imagine that you will not accept this excuse.
I recall that my friend Ralph Peck used to give his students the assignment of writing a project geotechnical report with analyses and recommendations on a single sheet of 8½ by 11 inch paper. Ralph used to say that concise, clear writing is an indication of clear thinking. But, I'm a story teller and I like to be a bit long winded (some might say more than a bit). How can I argue with Ralph's “clear thinking” philosophy? I guess I can't argue. I give up. Here is my explanation of the complexities of landslides as clear and concise as I can put it. But first, let me illustrate my point by one short story.
Working example
A client of my called one morning and asked me the famous landslide question, “Why is my computed factor of safety for our slope different than yours? We used the same geometry, the same soil parameters, everything was the ...
