Model tests on free-standing passive pile groups in sand

A number of tests have been conducted to investigate response of vertically loaded capped pile groups in sand undergoing uniform lateral soil movement. The development of shear force, bending moment and deflection along the piles was measured. Presented in this paper are 4 tests on 2-pile free-standing groups, with a view to establish solutions for predicting the pile response. It was concluded that (1) maximum bending moment Mmax is largely linearly related to the sliding force Tmax in stable and moving layers; (2) The combined impact of pile-cap fixity, soil movement profiles, and axial load may be quantified by a single moment (Mo); (3) Each pile in a group behaves as free-head in stable layer or semi-fixed head in sliding layer, with a floating base; and (4) The previous solutions for single piles were extended to simulate Mmax and Tmax for piles in groups.