张宇. 2007: P波、SH波、面波数据分析方法的对比与剪切模量的确定. 工程地质学报, 15(S1): 685-692.
    引用本文: 张宇. 2007: P波、SH波、面波数据分析方法的对比与剪切模量的确定. 工程地质学报, 15(S1): 685-692.
    ZHANG Yu. 2007: A COMPARISON OF METHODS FOR THE ANALYSIS OF COMPRESSIONAL,SHEAR, AND SURFACE WAVE SEISMIC DATA, AND DETERMINATION OF THE SHEAR MODULUS. JOURNAL OF ENGINEERING GEOLOGY, 15(S1): 685-692.
    Citation: ZHANG Yu. 2007: A COMPARISON OF METHODS FOR THE ANALYSIS OF COMPRESSIONAL,SHEAR, AND SURFACE WAVE SEISMIC DATA, AND DETERMINATION OF THE SHEAR MODULUS. JOURNAL OF ENGINEERING GEOLOGY, 15(S1): 685-692.

    P波、SH波、面波数据分析方法的对比与剪切模量的确定

    A COMPARISON OF METHODS FOR THE ANALYSIS OF COMPRESSIONAL,SHEAR, AND SURFACE WAVE SEISMIC DATA, AND DETERMINATION OF THE SHEAR MODULUS

    • 摘要: 地震折射法普遍用来圈定岩石和地层的几何形态。此外,也可用于提取与速度相关的信息,比如:土壤和岩石的力学性质,然而这需要一个地表下速度变化的可靠模型。对折射P 波和SH波的首波以及表面波数据进行分析有3种不同的技术: 追逐时距曲线的延迟时间法, 层析成像法和面波多波分析(MASW)法。从前两种方法的比较结果看,对于高分辨率分层使用传统的追逐时距曲线的延迟时间法是最好的,层析成像法(P波测量)不能发现地下水位面,但是可测量到地下水位面附近速度的逐渐变化;另一方面, 对于介质速度的逐渐增加,传统的SH波的探测无用,但层析成像法却较适合。 此外, 层析成像法或 MASW法适宜用来建立细微的空间速度变化模型,与折射SH波层析成像法相比,MASW法显示略低的速度,而显示的速度梯度也是反向的。 这项研究同样适用于原位剪切模量的比较, 等等。也就是用剪切波速度进行计算, 并采用经验关系确定剪切模量,对于砂的剪切模量,相对于原位测量,经验关系值要更大一些。

       

      Abstract: The seismic refraction method is commonly used to determine the lithology and stratigraphic geometry of geological sites. Beyond this application there is also the potential to extract additional velocity-related information such as mechanical properties of soils and rocks. However, this requires a reliable model of the subsurface velocity variations. Refraction data, P- and SH-wave first arrivals, and surface waves were analyzed using three different techniques: delay-time in combination with ray-tracing, tomography and multichannel analysis of surface waves (MASW). Results from the first two techniques were compared, which showed that sharp high-contrasting layering is best imaged by the traditional method, delay-time followed by ray-tracing. The tomographic method was unable to detect the water table in the P-wave survey but resolved near-surface gradational velocity changes. On the other hand, in the SH-wave survey the traditional method was not useful because of gradually increasing velocities, which were better suited to the tomographic method. Furthermore, to produce spatially detailed velocity-variation models the tomographic or the MASW methods are applicable. The MASW model showed somewhat lower velocities compared to the SH-refraction tomographic model and, in contrast, showed inverted velocity gradients. This study also presents a comparison between the shear moduli measured in situ, i.e. calculated from shear wave velocities, and determined using empirical relationships. The empirical relationship for sand gives higher values for shear moduli than those measured in situ.. 2006 Elsevier B.V. All rights reserved.

       

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