地震断层对管道压溃压力的影响

利用有限元软件ABAQUS,结合用户自定义Python程序,开展地震断层作用下深海管道局部变形和压溃过程的数值模拟。分析均质土体和随机分布土体模型的地震断层位移大小对管道局部变形的影响,并分析断层诱发的局部挤压变形对管道压溃压力的影响。研究表明:相比于断层走向与管道轴线方向垂直的走滑断层,断层走向与管道轴线方向夹角为45°的走滑断层作用下管道的压溃压力较小,且当断层走向为管道轴线方向逆时针旋转45°时,左旋走滑断层作用下管道的压溃压力低于右旋走滑断层作用下的管道压溃压力。断层位移相同时,管道径厚比越大,压溃压力越小。考虑土壤随机性时,由于APIX65钢制管道刚性较大,且管道两侧土体内聚力和摩擦角分散于均质土壤土体参数均值两侧,因此断层作用过程中管道受到的土压力在均质土壤模型中的土压力数值处上下波动。

Effect of earthquake fault on the collapse pressure of pipeline

Numerical simulation on the local deformation and collapse process of the deep-sea pipelines under the action of earthquake faults was carried out by using the finite element software ABAQUS and the user-defined Python program. The influence of the fault displacement of the homogeneous soil and randomly distributed soil model on the local deformation of pipeline was analyzed, and the influence of local compression deformation induced by the fault on the pressure of pipeline collapse was studied.The results show that compared with the strike-slip fault whose strike is perpendicular to the pipeline axis, that with an angle of 45° between the fault strike and the pipeline axis induces smaller collapse pressure of the pipeline. And when the strike of the strike-slip fault rotates counterclockwise 45° from the direction of the pipeline axis, the collapse pressure of the pipeline under the action of the left-lateral strike-slip fault is lower than that under the action of the right-lateral strike-slip fault. With the same fault displacement, the larger the diameter-thickness ratio is, the smaller the collapse pressure is. When the soil randomness is taken into account, since the rigidity of the APIX65 steel pipe is high and the cohesion and friction angle of the soil on both sides of the pipe are dispersed on both sides of the mean value of the soil parameters in homogeneous soil, the soil pressure to the pipe during fault action fluctuates up and down in homogeneous soil model.