APPENDIX A EXAMPLE P-Y CURVES AND PARAMETERS FOR VARIOUS SUBSURFACE CONDITIONS BASED ON AVAILABLE PUBLISHED SOURCES This appendix provides example p-y curves and parameters for various subsurface conditions, and is not intended to present a comprehensive list of all p-y curves available in literature. Instead, this appendix presents the most commonly used p-y curves in geotechnical practice, and discusses the equations that are used to construct such curves. The p-y curves presented in this appendix are also included in the computer programs LPILE, GROUP and FB-Multipier. With this appendix, the user should be able to understand the main parameters affecting the p-y curves construction, and how the p-y curves vary for different site conditions. The following p-y curves are presented • P-y Curve for Soft Clay with Free Water (Matlock 1970) • P-y Curve for Stiff Clay with Free Water (Reese et al. 1975) • P-y Curve for Stiff Clay with No Free Water (Reese and Welch 1975) • P-y Curve for Sand (Reese et al. 1974) • P-y Curve for Weak Rock (Reese 1997) • P-y Curve for Liquefied Sands (Rollins et al. 2005) Sloping Ground A.1 P-Y CURVE FOR SOFT CLAY WITH FREE WATER (MATLOCK 1970) Matlock (1970) proposed a p-y criterion for soft clay underwater based on results of pilot tests. Soft clays are those with undrained shear strength (S u ) ranging from 250 to 500 psf. Figure A-1(a) shows the main characteristics of the static p-y curve for soft clay. In this relationship, the soil resistance (p) is normalized by the ultimate soil resistance (p u ) and is expressed as a function of the lateral deflection (y), which is also normalized by the deflection that occurs at 50 percent of the ultimate resistance (y 50 ). Under static loading conditions, the resistance of soft clay increases monotonically as a function of deflection until the ultimate resistance is reached. To reflect the strength degradation, a correction is applied to the p-y curve for short term, monotonic loading of Figure A-1(a). Under cyclic loading conditions, the resistance achieves a maximum value and then decreases as the normalized deflection increases. The curve for cyclic conditions also depends on the depth that is considered for soils at a depth (z) greater than a critical depth (x r ), it is considered that the clay flows around the pile and that p = 0.72 p u for y/y 50 > 3; for x < x r , p decreases from 0.72 p u at y/y 50 = 3, to a smaller value, 0.72 p u x/x r , at y/y 50 = 15, as indicated in Figure Ab) and presented below.
