Estimating the allowable spacing of soldier pile wall

[MelCao]

Hello Everyone:
I design many soldier pile retention walls for some excavations. there is one thing I am not sure how to estimate the allowable spacing of the piles allowing for the arhing effect between the piles.
I am wondering if anyone can reccommend some good references to explain how we estimate the spacing based on geotechnical conditions, surcharge loads and excavation depth etc.
Many thanks to anyone who replies.
I also would be happy to share many of my books or standards to you guys.

 

[tsek]

Try CALTrans trenching and shoring manual.

http://dot.ca.gov/hq/esc/construction/manuals/OSCCompleteManuals/TrenchingandShoringManual2011.pdf