Side Friction Mobilization Rates for Laterally Loaded Piles from the Pressuremeter

Pile foundations in the offshore environment are frequently called upon to resist high horizontal load. Many pressuremeter methods have recently been developed to design piles, including techniques to formulate soil spring P-y curves directly from pressuremeter test results. Lateral soil resistance is now recognized to arise from two components: side shear and front resistance. The field measurement of mobilization rates and prediction of lateral side shear has never been made. This paper reports the attempts to measure lateral friction rates in sand and clay by employing torsion testing as a “yardstick” method. Pure lateral shears are mobilized and the effects of depth and installation method can be studied qualatively. It is suggested that since the soil shear modulus, G, is the controlling variable, the pressuremeter is a suitable insitu tool to duplicate pile installation disturbance and predict side shear mobilization rates.