Change in soil strength adjacent to closed end metal shell pile

[16adams]

I have been asked by a client to determine the change in soil strength along a metal shell pile. All the books that I have tell me that in a cohesive soil the strength is reduced during driving and will be regained and increased in some cases say a month after driving. I am being asked to qualify and quantify this. Does anyone know of a text book or other resource I could get my hands on to get more information on this?

Thanks

 

[oldestguy]

There may be texts abut this regain of strength, but my recommendation is to call any large pile driving contractor and ask the question. They probably would be very helpful to find someone is asking a question they can readily answer.
It has been my experience significant strength gain can be experienced in one hour. When it is necessary to stop driving to weld on a new section, it usually is noted even in that short time.

There are some of those persons in this group also so stick around.

 

[Ron]

In some materials, particularly as you've mentioned cohesive soils, the remolded strength goes up. In my experience with coastal plains marls, it doesn't take that long to regain and increase strength.

As OG noted, ask a few pile driving contractors...in particular ask them for "retap" strength changes. You'll probably get more data from mandrel driven shell piles than closed-end steel pipe.

 

[16adams]

Thank you for your comments. I ended up discussing this issue with Dr. James Long, University of Illinois. He and some graduate students wrote a paper regarding the topic.

Thanks again,