Permanent ground movements due to seismic fault rupture, ground subsidence or liquefaction-induced lateral spreading may result to failure of buried pipelines crossing the affected areas, due to the development of excessive bending and axial pipe strains. Verification of pipe integrity against such actions and design of mitigation measures is based on analyses with nonlinear beam-on-non-linear Winkler foundation models, where the soil reaction developing on a pipe as result of differential ground movements is modelled by means of elastoplastic springs. This note presents a new set of guidelines and expressions for determining the parameters of Winkler springs applicable to the analysis of steel pipes backfilled with sand and subjected to differential movement with a lateral, vertical-upwards and/or vertical-downwards component. The guidelines, collectively referred to as UoN recommendations, are accordingly employed in the parametric stress analysis of a buried steel pipe crossing an oblique seismic fault. Results of this parametric analysis demonstrate that adoption of the UoN recommendations in the analysis workflow results in considerably lower pipe axial and bending strains, compared to analyses based on current conservative methods, and thus more realistic and economical design solutions.

由于地震断层破裂，地面沉降或液化引起的横向扩展而引起的永久性地面运动，可能会由于过度弯曲和轴向管道应变的发展而导致穿越受影响区域的地下管线失效。针对此类行为的管道完整性验证和缓解措施的设计是基于非线性非线性梁对非线性Winkler基础模型的分析，该模型通过弹塑性弹簧模拟了由于地面运动差异而在管道上产生的土壤反应。 。本说明提供了一组新的准则和表达式，用于确定Winkler弹簧的参数，这些参数适用于分析回填有沙子并经受横向，垂直向上和/或垂直向下分量的差分运动的钢管。准则，因此，UoN建议用于穿越倾斜地震断层的埋入式钢管的参数应力分析。此参数分析的结果表明，与基于当前保守方法的分析相比，在分析工作流程中采用UoN建议可显着降低管道的轴向和弯曲应变，从而提供更现实，更经济的设计解决方案。