软黏土海床条件下的管道侧向失稳预测模型

Analytical Model for Predicting Lateral Instability of a Submarine Pipeline on the Soft Clayey Seabed

针对软黏土海床条件,基于被动土压力理论建立了海底管道侧向失稳预测模型。利用准静态平衡分析,该模型将极限侧向土阻力分解为被动土压力和滑动土阻力两个分量。验证分析表明,模型预测结果与文献[3]实验结果吻合较好。参量研究发现,在稳态海流作用下,随着软黏土不排水抗剪强度增大,维持管道在位稳定所需的最小埋深呈幂指数减小趋势;同时,极限侧向土阻力中的滑动土阻力分量呈非线性增大,相应的被动土压力分量则逐渐降低。

Based on the passive soil pressure theory,an analytical model for predicting the pipeline lateral instability is developed for the soft clay seabed condition.By using quasi-static equilibrium analysis,the ultimate lateral soil resistance can be decomposed into a passive-pressure component and a sliding-resistance component.The verification shows that the analytical results predicted with the present model are in good agreement with the experimental ones by Wagner et al.（1989）.It is indicated by parametric study that,with increasing the undrained shear strength of soft clay,minimum values of pipeline embedment to keep the pipeline laterally stable under steady currents decrease exponentially.Meanwhile the sliding-resistance component of the total soil resistance increases,but the passive-pressure component is reduced correspondingly.