Geotechnical properties vary in space with statistical parameters (mean, deviation, correlation length) that are characteristic for each sediment and formation history. The effects of spatial variability on the macro-scale mechanical properties of soils are investigated using Monte Carlo non-linear finite element simulations. Boundary conditions include radial loading, zero-lateral strain loading, and drained/undrained deviatoric loading. Numerical results show that internal heterogeneity leads to higher compressibility, lower horizontal load transfer, and lower shear resistance in both undrained and drained loading. Copyright ASCE 2006.