These are esoteric terms indeed, but that said, fundamental to geotechnical engineering. ‘Burn the shear strength equation into your brains’ we were told by our soil mechanics lecturer. And indeed we did. For those not in the know, the basic shear strength equation is:
However we are going to keep things simple here, so I won’t involve us in any more equations. Suffice it to say, ‘c’ is the cohesion of a soil, Sigma the normal load, and Phi the friction angle of the soil. Foundation design and slope stability assessments hinge on the shear strength parameters of the materials. Question is, how does one arrive at these parameters? By carrying out some testing. Triaxial tests are arguably the best way of doing this, but they can be incredibly complex, time consuming and expensive. We don’t do much of them here in South Africa. We do have an alternative – the less complex and cheaper shear box test. Again we don’t do too many of them here. What we do occasionally do are some DPL or DCP tests, and armed with our magic numbers plug them into our fantastic shear strength equation and hey presto, we have an answer. Or do we?
I shall digress somewhat now and talk about a book I keep beside my bed – “The Little Big Things” by Tom Peters. Now Tom is an American, and Americans can be prone to lapses into Pollyanna niceties and the ‘feel good’ syndrome, but Tom is another creature altogether. He tells it as it is. He is also an engineer which says a great deal. The book is about the pursuit of excellence, a subject to which he brings his own particular brand of passion. Mostly the book is about paying attention to the small things, which are actually the big things. He talks of integrity and sacred trust, which may be old fashioned concepts in this day and age, but he is perhaps of an earlier generation. And talking of telling things as they are, on his blog he got on his high horse about the oil spill in the Gulf of Mexico last year, and had this to say:
I also find myself beset with newfound anger-outrage at numerous engineers employed by BP, et al. (Many an “al.” it would appear.) Outrage not at “BP engineers,” but outrage at Arthur N. Smith [fictitious name], certified and licensed engineer. And doubtless dozens and dozens, probably hundreds, of his cohorts.
BP seems to have gotten it wrong on a dozen dozen dozen engineering dimensions. In the name of cost control or whatever. I don’t give a shit about the cost control issues, real as I know they are. I give a hundred shits about the fact that Arthur Engineer and Ralph Engineer and Mary Engineer, cross-pressures notwithstanding (that’s life), abrogated their professional responsibilities as … individuals. Arthur and Ralph and Mary are probably good parents—but professionally they screwed their fellow citizens to a fare-thee-well.
And I’m pissed off.
Very pissed off.
Arthur and Ralph and Mary have bills to pay. And the economy is tough. And their bosses, responding to their bosses, doubtless did put merciless pressure on them.
Hence my empathy is high.
But in the end I am appalled. They have cost us lives and economic and environmental damage of epic proportion. Because they lacked the will and integrity to blow their professional whistles and stand up for the discipline to which they have sworn allegiance.
They are (individually) a disgrace to the great tradition of engineering of which I am the smallest part. So I’m taking this personally.
Strong words perhaps, but I admire his passion. Which now brings me back to geotechnics. I seem to spend much of my time writing proposals and filling in BoQ’s. Some of these BoQ’s are for large dam contracts which I get to see only because we are pricing the instrumentation side of things. What I find appalling is that in so many of these projects, ranging from the smallest house investigation to a large dam, the geotechnical aspects are not given the attention they deserve. In fact on the last dam job we priced there was no provision for any geotechnical staff in the BoQ. Perhaps worse, the geotechnical scope of works has been written by someone who doesn’t understand the subject, and we, the geotechnical consultants, have to price a job which we believe does not adequately address the geotechnical issues. Putting in money for some extra testing for example makes my bid uncompetitive, but then there are salaries to pay, mouths to feed and the landlord wants his money by the 1st of the month, so let us just do the minimum to get the job. Excellence indeed!
Which brings me back to those shear strength parameters we were discussing earlier. I want to know what the behaviour of a soil is. I don’t want to suck my thumb, or whatever else we are meant to do to arrive at those numbers. I have a duty of care, a sacred trust, a professional responsibility to make sure it is done right. We do not want to find ourselves in the same position of our erstwhile BP engineers discussed above. And so I must take a leaf out of Tom’s book and bring some passion to this issue. And so we need to run that race of excellence, all of us, from the foundations to the top structure. Please.
“I believe that the Mother of … all Innovation is fury. Abiding anger at the way things are….. coupled with “irrational” determination to beat back the innumerable protectors of the status quo and find and implement a better way.”
Tom Peters 2010