Estimate Quantity of Downdrag on Driven H Piles

[lancewatson]

I have a foundation project that I am constructing that requires driven steel H-Piles of an approximate length of 100' - 0" with batters of 1:3 and 1:2 in a 2 to 1 ratio. I am intermittently experiencing soil downdrag around the driven piles installed to date. This void must be backfilled a sand / cement / bentonite slurry mixture and I want to estimate a cost to repair for the overall project. (We have driven just over 400 of over 2000 piles.) The soils report appears fairly consistent to the first 30 feet of depth with a water content of approximately 40%; shear strength of 0.25 tons / sq. ft; wet density of 110 lbs/ cu. ft.; PI of approximately 40 at a LL of 60. Is there a way to calculate an anticipated percentage of down drag based upon the information in the soils boring report?

 

[BigH]

What stratum are the piles being driven to?

 

[ishvaaag]

https://ceprofs.civil.tamu.edu/briaud/NCHRP_Downdrag.pdf

http://upcommons.upc.edu/e-prints/bitstream/2117/2635/1/47.pdf

http://www.straits-engineers.com/publications_pdf/publication_6.pdf

http://www.scribd.com/doc/14045960/Deep-Foundations-using-LRFD-Method

http://www.fhwa.dot.gov/engineering/geotech/pubs/gec8/gec8.pdf

http://books.google.es/books?id=QAr...snum=8&ved=0CCMQ6AEwBzgK#v=onepage&q=&f=false

http://books.google.es/books?id=b7f...Q6AEwBQ#v=onepage&q=downdrag estimate&f=false

This one says downdrag is wanted deduced first-hand by the geotech:

http://www.dot.il.gov/bridges/Design Guides/AGMU 10.2-Geotechnical Pile Design Guide.pdf

Hope some of these helps.

 

[lancewatson]

It's hard to read the copy of the copy of the boring log I have been given; however, the pile at the approximate tip elevation appears to typically be protruding into an "M", "M,SL" strata.