Finite element undrained analysis with a pore pressure tension cut off

Tensile pore pressure could develop in undrained analyses when a frictional soil exhibits plastic dilation. To avoid this effect, two numerical schemes are outlined suited for implementation in standard F.E. codes for non-linear, two-phase analyses. The first one introduces a unilateral constraint on the nodal pore pressures and involves operations on the assembled system matrix. The second approach requires calculations solely at the element level. Some test examples illustrate the effects of the mentioned pore pressure limit on the results of elastic-plastic undrained analyses.