P-Y Curves for Reese Sand

The implementation of p-y curve for Reese Sand in PileLAT is based on Reese et al. (1974) for both static and cyclic loading conditions. The p-y curves are shown in the figure below.

The values of Ks are determined for submerged sand and sand above the water table based on the table below.

The ultimate resistances of sand at shallow depths (Pst) and deep depths (Psd) are calculated based on the equations below. The depth of transition (Zt) can be determined by comparing the value of each equation at the specified depths.

The ultimate resistance of sand at the shallow depths is determined according to:

The ultimate resistance of sand at deep depths is determined according to:

where Z is depth below ground surface, Ko is coefficient of earth pressure at rest, φ' is angle of internal friction of sand, β=45°+φ'/2, α=φ'/2, Ka=[tan(45°-φ'/2)]^2 and D is pile diameter.

Ps is then determined by using the smaller values of Pst and Psd as below:

Pu is determined at Yu of 3D/80 based on the equations below:

Pm is determined at Ym of D/60 based on the equations below:

The empirical parameters As, Ac, Bs and Bc can be determined through the following figures.

Variation of As and Ac with the depth for Reese sand model (Reese and Van Impe 2011)

Variation of Bs and Bc with the depth for Reese sand model (Reese and Van Impe 2011)

The straight-line portion of the p-y curve is based on the following relationship:

The parabolic section of the p-y curve between points K and M is based on the following relationship:

yk at point K is determined based on the equation below:

References:

• Reese, L.C., W.R. Cox & F.D. Koop. (1974). Field testing and analysis of laterally loaded piles in sand. Proceedings of the VI Annual Offshore Technology Conference, Houston, Texas, 2(OTC 2080): 473-485.

• Reese, L.C. & W.F. Van Impe. (2011). Single Piles and Pile Groups Under Lateral Loading, 2nd Edition. London: Taylor & Francis Group.