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Green's functions for uniformly distributed loads acting on an inclined line in a poroelastic layered site 总被引:2,自引:1,他引:1
Based on one type of practical Biot's equation and the dynamic-stiffness matrices ofa poroelastic soil layer and half-space, Green's functions were derived for unitformly distributed loads acting on an inclined line in a poroelastie layered site. This analysis overcomes significant problems in wave scattering due to local soil conditions and dynamic soil-structure interaction. The Green's functions can be reduced to the case of an elastic layered site developed by Wolf in 1985. Parametric studies are then carried out through two example problems. 相似文献
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以基岩上单-土层场地为例,计算分析了在斜入射平面SH波作用下弹性层状半空间中无限长洞室附近的地表位移.研究表明,层状半空间中地下洞室对波的散射与均匀半空间情况存在显著差别.层状场地由于考虑了场地自身的动力特性,使得洞室附近地表位移幅值的空间变化更为复杂,基岩与土层刚度比、土层厚度对散射效应均有着重要影响.随着基岩与土层刚度比的增大,地表位移幅值整体上逐渐增大;随着土层厚度的增大,土层对地表位移幅值的影响逐渐减小.在频域解答的基础上,给出了层状半空间中洞室对斜入射SH波散射的时域解答,并以Ricker波为例进行了数值计算. 相似文献
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The indirect boundary element method (IBEM) is used to study three-dimensional scattering of obliquely incident plane SH waves by an alluvial valley embedded in a layered half-space. The free-field response of the layered half-space is calculated by the direct stiffness method, and dynamic Green's functions of moving distributed loads acting on inclined lines in a layered half-space are calculated to simulate the scattering wave field. The presented method yields very accurate results since the three-dimensional dynamic stiffness matrix is exact and the moving distributed loads can act directly on the valley boundary without singularity. Numerical results and analyses are performed for amplification of obliquely incident plane SH waves around an alluvial valley in a uniform half-space and in single layer over half-space. The results show that the three-dimensional responses are distinctly different from the two-dimensional responses, and the displacement amplitudes around alluvial valleys in a uniform haft-space are obviously different from those in a layered half-space. 相似文献
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供水管网压力监测点的优化布置可以提高供水管网健康监测的效率,为此在回顾了以供水管网优化调度为目的的压力监测点优化布置研究基础上,提出了一种以城市供水管网健康监测为目的的压力监测点优化布置的实用方法。该方法通过假设在管网的不同位置存在不同程度的局部漏损,并逐节点假设压力监测点,再以局部漏损对监测点压力的影响度大小为目标来实现压力监测点的优化布置。文中通过算例分析对方法的有效性进行了验证。研究表明,压力监测点多应布置在对压力比较敏感的管网末端,与实际工程经验一致;漏损大小对压力影响度的局部排序有一定影响,但影响非常小;本方法可用于小的局部漏损的监测,也可用于大的爆管事故的监测。 相似文献
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弹性层状半空间中凸起地形对入射平面SH波的放大作用 总被引:7,自引:0,他引:7
对Wolf理论进行拓展,使之可解决凸起地形对波的散射问题,进而利用间接边界元法,求解了弹性层状半空间中凸起地形对入射平面SH波的放大作用问题。本文模型的显著特点之一是考虑了层状半空间的动力特性以及层状半空间和凸起地形的阻尼;特点之二是计算精度高。文中以基岩上单一土层中半圆凸起地形对入射平面SH波的放大作用为例进行了数值计算分析。研究表明,基岩上单一土层中凸起地形对入射平面SH波放大作用和均匀半空间中凸起地形有着本质的差别;土层动力特性不仅影响凸起地形地表位移的幅值,还会影响地表位移的频谱;阻尼会显著降低凸起地形对高频波的放大作用。 相似文献
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依托于某大直径盾构隧道工程项目,建立了基于黏弹性边界的地层-结构时程分析有限元模型。首先,基于振动台试验结果,验证了有限元数值模拟方法的有效性;进而,从软硬土层剪切波速比、软硬土层与隧道的相对位置、隧道埋深等三个方面,系统开展了上软下硬场地对大直径盾构隧道地震响应的影响研究。研究表明:上软下硬场地中的大直径盾构隧道弯矩最大值始终出现在软硬土层分界线附近。随着软硬土层剪切波速差异的增大,隧道的弯矩、剪力和接头张开量都有明显的增大,而隧道轴力和直径变形率的增大幅度较小。软硬土层与隧道的相对位置对隧道内力的影响具有不确定性。随着隧道埋深的增大,隧道弯矩、轴力和直径变形率逐渐增大。 相似文献