Recom-Tiended Skir: FricLicn Values for Sand 





Installation 





6 

 (deg) 



K 



^'.' 



max 



Soil 



psi 



j kPa 



Sand 



driven or drilled and 



grouted 



(!i-5 



1 

 :0.5 



13.9 



96 



Silty sand 



driven or drilled and 



grouted 



(f-S 



i ^-^ 



11.8 



81 



Sandy silt 



driven or drilled and 



grouted 



0-5 



|0.5 



9.7 



67 



Silt 



driven or drilled and 



grouted 



0,-5 



iO.5 



6.9 



48 



Calcareous sand 



drilled and grouted 

 driven 



$-5 

 $-5 



j 0.5 

 i 0.5 



11. 8-' 

 1.7 



81^> 

 12 



"Depends on installation technique; may be as low as 3 kPa (0.5 psi). 



Anchor Pile Loading 



- Effects of combined axial and lateral loading are poorly understood, 

 currently treated separately. 



- Repetitive loading can cause large increase in la^teral pile deflec- 

 tion. Methods to dampen/ avoid repetitive loading should be consid- 

 ered for piles in loose sand/soft silt seafloors. 



- Chellis (1969), suggests "a rough assumption" coefficient of 

 horizontal subgrade reaction for soils of high relative density 

 might be reduced by 1/2, for soils of low relative density - 

 reduced to 1/4 initial value (data provided for plate anchors 

 may be useful as a guide in evaluating effects of repetitive 

 loading) . 



- Effects of repetitive loading on vertical piles are speculative, 

 (research projects underway in United Kingdom and Norway). 



39 



