This paper presents a numerical study on passive earth pressure under undrained conditions. First, a simplified problem is investigated in order to evaluate the resulting earth pressure for a parallel movement of a rigid wall. It is shown that for undrained conditions the type of constitutive model employed has an influence on the limiting passive earth pressure. Comparison with limit analysis is provided whenever possible, giving confidence that the finite element results are reliable. In a second study, a simplified deep excavation problem is analysed where the positive effect of negative excess pore water pressures developed during undrained excavation increases the factor of safety against global failure. However, this effect is only temporarily and it is shown that standard strength reduction procedures to calculate factors of safety, as applied frequently in practice, are not well suited for this type of problems. An alternative way is therefore suggested. Again, the influence of the constitutive model is addressed, and it is shown that simple elastic-perfectly plastic models may not be conservative. In addition the influence of geometric effects is highlighted.

本文介绍了不排水条件下被动土压力的数值研究。首先，研究了一个简化的问题，以评估刚性墙平行运动所产生的土压力。结果表明，对于不排水条件，所采用的本构模型类型对限制被动土压力有影响。尽可能提供与极限分析的比较，以确保有限元结果是可靠的。在第二项研究中，分析了一个简化的深基坑开挖问题，其中在不排水开挖过程中产生的负超孔隙水压力的积极影响增加了防止整体故障的安全系数。然而，这种影响只是暂时的，并且表明计算安全系数的标准强度降低程序，在实践中经常应用，不太适合这类问题。因此建议采用另一种方式。同样，本构模型的影响得到解决，并表明简单的弹性-完美塑性模型可能不是保守的。此外，突出了几何效果的影响。