About the Efficiency of Numerical 1-D and 2-D Modelling of Site Effects in Basin Structures
About the Efficiency of Numerical 1-D and 2-D Modelling of Site Effects in Basin Structures
复制标题
关于盆地结构场地效应的一维和二维数值模拟的效率
DOI：
10.1007/s000240050002
复制
发表时间：
2000
影响因子：
2
通讯作者：
P. Bard
中科院分区：
文献类型：
--
作者：
J. Riepl;J. Zahradník;V. Plicka;P. Bard
摘要-在本研究中，我们使用四种不同的技术比较了从局部站点放大效应的实验估计获得的结果和从数值模拟获得的结果。我们受益于对近地表结构的极其精确的了解和对当地放大系数的实验估计，这些估计是由希腊北部一个欧洲试验场的一个跨越沉积盆地的密集阵列记录的地震弱运动数据确定的。对模拟局部放大效应的不同建模技术(一维技术和三种二维技术)的可能性和局限性进行了测试。通过数值技术计算的放大仅在时间域和直接在频域中与实验研究的观测数据进行了定性比较。？因此，我们得出结论，在复杂的地下几何结构的情况下，一维模型低估了绝对放大水平的放大模式，并且无法正确地解释共振频率，至少对于高于基模的模式是如此。如果考虑到比平面波更真实的入射波场，二维模拟可以显示基频，并且不仅在基频，而且在更高的频率上也显示出足够的放大。二维数值模拟很好地确定了最低频率放大的总趋势，因此可以为地震危险性分析提供信息。
Abstract—In the present study we compare results obtained from experimental estimates of local site amplification effects with those from numerical modelling using four different techniques. We benefit from an extremely precise knowledge of the near-surface structure and experimental estimates of the local amplification factors which are determined from seismic weak-motion data recorded by a dense array across a sedimentary basin at a European test-site in Northern Greece. The possibilities and limitations of the different modelling techniques (a 1-D technique, and three 2-D techniques) to model the effects of local amplification effects are tested. Amplifications calculated by the numerical techniques are only qualitatively compared with observed data from experimental studies in the time domain and directly in the frequency domain.¶As a result we conclude that, in the case of a complex subsurface geometry, 1-D modelling underestimates the amplification patterns in terms of absolute amplification level, and cannot correctly account for resonant frequencies, at least for modes higher than the fundamental mode. If a more realistic incident wave field than just a plane wave is taken into account, 2-D modelling reveals the fundamental frequency and shows adequate amplifications not only at the fundamental frequency but also at higher frequencies. The general trend of the amplifications at the lowest frequencies is well determined by the 2-D numerical modelling, and can therefore supply information for seismic risk analysis.