跨断层埋地管道基于性态的抗震设计参数研究

Study on Performance-based Seismic Design Parameters of Buried Pipelines Crossing Fault

为了解决跨断层埋地管道基于性态的抗震设计方法,以埋地钢质管道抗震设防标准为出发点,以管道失效概率为衡量指标进行管道性态水平划分,提出了不同类别管道在不同设防地震下的性态目标.针对单体管道,采用Newmark-Hall理论计算法,建立了基于容许长度变化的功能函数,以提高一个性态水平为原则,进行重要性系数的计算.考虑到Newmark-Hall模型过于简化,非线性分析方面存在欠缺,故采用非线性有限元分析法,分析了埋深、管道直径、壁厚、管土摩擦系数和管材钢级这5项参数对管道轴向拉应变、压应变的影响,并根据拟合的管道最大应变回归公式建立了基于容许应变的功能函数,进行重要性系数的比较验证.结果表明两者计算结果一致,为跨断层埋地管道的抗震性态设计提供了基础参数.

In order to solve the problem of backward seismic design of buried pipeline crossing fault, a seismic design method based on performance is proposed.Taking the seismic fortification standard of buried steel pipelines as the starting point, and the pipeline failure probability as the measurement index to divide the pipeline performance level, the performance targets of different function classes of pipelines under different fortification earthquakes are proposed.For the single pipeline, the Newmark-Hall theory calculation method is used to establish a performance function based on the allowable length change, and the importance coefficient is calculated based on the principle of improving a behavior level.Considering the simplification of Newmark-Hall model and the lack of nonlinear analysis, the influence of five parameters, such as buried depth, pipe diameter, wall thickness, pipe-soil friction coefficient and grade of pipe, on the axial tensile strain and compressive strain of pipe is analyzed by using nonlinear finite element method, and a performance function based on allowable strain is established according to the fitted pipeline maximum strain regression formula, and the importance coefficient is compared and verified.The results show that the two calculation results are consistent, which provide accurate parameters for the design of buried pipelines across faults, and provide a preliminary idea for the realization of performance-based seismic design.