It is of great necessity to achieve the efficient and accurate representation of ground motion fields considering the spatial variation of which possess paramount importance to the seismic safety and reliability evaluation of lifeline systems. To circumvent the difficulties caused by the decomposition of cross power spectral density (PSD) matrix and the interpolation between discretized spatial points in the spectral representation method (SRM) for uni-dimensional multi-variate (1D-nV) stochastic vector process (regarded as discrete stochastic field), a wavenumber-frequency SRM (WSRM) for simulating multi-dimensional uni-variate (mD-1V) spatial-temporal stochastic field (regarded as continuous stochastic field) has been developed for years. In this paper, an updated WSRM (UWSRM), which can reduce the number of elementary random variables, is proposed for simulating the 2D-1V stochastic ground motion fields. Compared with the conventional WSRM (CWSRM) which belongs to the Monte Carlo simulation schemes, merely two elementary random variables are required to realize the precise modeling of ground motion fields. For the sake of facilitating the calculation, the UWSRM embedded in the Fast Fourier Transform (FFT) technique is applied to simulate the stochastic ground motion fields. Numerical results including the comparison of the accuracy and efficiency with the CWSRM verify the effectiveness of the UWSRM. Moreover, to illustrate the application prospect of the UWSRM, the refined random seismic response analysis of a buried pipeline network is implemented by combining with the probability density evolution method (PDEM). The analysis results preliminarily demonstrate the applicability of the UWSRM in lifeline systems.

考虑到地面运动场的空间变化对生命线系统的地震安全性和可靠性评估至关重要，因此，有必要实现对地面运动场的高效，准确的表示。为了规避一维多元（1D- n V）随机矢量过程的频谱表示方法（SRM）中的交叉功率谱密度（PSD）矩阵分解和离散空间点之间的插值所造成的困难（考虑作为离散随机场），用于模拟多维单变量（m的波数频率SRM（WSRM）D-1V）时空随机场（被认为是连续随机场）已经发展了多年。本文提出了一种更新的WSRM（UWSRM），它可以减少基本随机变量的数量，用于模拟2D-1V随机地面运动场。与属于蒙特卡罗模拟方案的常规WSRM（CWSRM）相比，仅需要两个基本随机变量即可实现地面运动场的精确建模。为了便于计算，将嵌入快速傅里叶变换（FFT）技术中的UWSRM用于模拟随机地震动场。数值结果包括与CWSRM的准确性和效率的比较，证明了UWSRM的有效性。此外，为了说明UWSRM的应用前景，结合概率密度演化法（PDEM），对地下管道网络进行了精细的随机地震反应分析。分析结果初步证明了UWSRM在生命线系统中的适用性。