This week we’ll look at the first chapter of the book. The whole business of “problem soils” is not straightforward because it’s a matter of degree. Given the nature of soils vs. other engineering materials, all soils are problem soils; it’s just that some soils pose a greater problem to those of us who choose to build on, under or next to them than others, greatly so in some cases.
Most of the problem soils identified in the chapter are clays: loess, expansive soils, residual silts and clays, etc. Organic soils are included in this list, although the best way to deal with most of these is to avoid them altogether. Most of the descriptions of these soils is qualitative rather than quantitative, and that’s the weakness of the whole discussion. While general awareness of these soils and the challenges they create is useful, some quantitative description would have been useful.
An example of this is the determination of the growth of expansive soils with changing water content. Many of the studies of the volume change in these soils produce results that are either too specific or too difficult to readily implement either in an academic setting (where qualitative discussions of these soils abound) or in practice. Some of this is addressed in DM 7.1, but a more thorough approach would have been appreciated. I tackled this issue by presenting van der Merwe’s method in a more detailed fashion than usual; some more of this here would have been helpful.
The last part of the chapter deals with specialty construction methods in a page diagram reminiscent of the old driven pile diagrams from the previous edition. These are helpful because many proprietary methods don’t get the coverage in undergraduate texts that would be useful in the field. Fortunately in these cases specific references to more detailed descriptions–including design information–are given. The documents referred to are available on this site.
And a word of thanks…
I want to thank all of you who ordered the new DM 7.2 after its introduction last month. And that was quite a few of you: this has been the most successful publication launch of any book I have offered since I started doing this in 2006. Thank you so much for your support of our publications; it means a great deal for the continuation of this site.
And then there was another surprise last week in the video launching of the book from the Geo-Institute:
Notice the book cover on the splash screen? I had no idea they would do that. The first volume noted that it had been on the bookshelves of engineers for many years, and at this point the only way to acquire these books in print (AFAIK) is here.
vulcanhammer.net 