Sinking Caisson/Shaft

[rebentle]

I am looking for informative sinking shaft/caisson publications to aid in design considerations. We are seeing more of this work in our area, and need to be more educated. Can anyone point me in the right direction?

 

[Zambo]

I don't have a book that covers this subject well. But out of interest are you sinking small (say 5m diameter down) circular shafts as access chambers etc or are you talkng about larger heavy civil engineering projects such as boxes or cofferdams.

What sort of soils do you expect to be working in?

 

[rebentle]

I work for a geotechnical consultant and we are getting design request from heavy civil firms. So far, we are seeing shafts up to 20 meters to up to 100 foot depths through wet silty clays and clayey sands.

This type of contruction is new in our area (Metro Detroit, Michigan), so we are trying to become more familiar to help with design services for contractors.

 

[Zambo]

Well that's a big heavy civils job. I was wondering if you were sinking smaller shafts, in which case there are some excellent precast options which mean you can easily sink a 3-5m diameter shaft to a depth of 10m in a shift.

The shafts you are considering are large and although segments similar to tunnel segments could be considered cast insitu lifts would probably be the method of choice.

 

[BigH]

I would suggest that you search in the Indian literature. Caisson foundations of that size - called Well Foundations in India - are very very common for big bridges - and even for some smaller ones. We had some 20 of them on our job in India - but didn't see too many of them done; financial probs of contractor. The publications of the Indian Roads Congress is a very good place to start. They have a monthly journal that is published. Dr. N. Som has a book on Foundation design that has a chapter on it. In sinking, it is very important that it is sank 'vertically' - and that monitoring be done religiously. You may need kentledge placed "off balance" in order to return your well to the vertical. I have a number of articles on this. bohicafries "at the rate of"
g mail dot com if you want. You can figure it out, I am sure.

 

[Zambo]

BigH, I have a book entitled "Deep Excavations a practical manual": Malcolm Puller: ISBN 0 7277 1987 4 which has a chapter on shaft sinking.

But I think there is a lot of experinece to be gained and the Indian literature may be of interest. I still think it would be better to define what the job is.

 

[BigH]

Zambo - true, but I think that the original post was just for getting his feet wet in the issue - to gain an appreciation of what is involved, etc. There is a nice chapter in Foundation Engineering by P.C. Varghese (Prentice-Hall India. Tomlinson's original Foundation book had good discussion too. The Indians use well foundations as a matter of course, not something that is from time to time - so their experience is definitely something to check out.