Vertical seismic shear wave profiling (VSSP) for engineering assessment of soils
Vertical seismic shear wave profiling (VSSP) for engineering assessment of soils
复制标题
用于土壤工程评估的垂直地震剪切波剖面 (VSSP)
DOI：
10.1071/eg990045
复制
发表时间：
1990
影响因子：
0.9
通讯作者：
J. Macgregor
中科院分区：
文献类型：
--
作者：
R. Whiteley;R. Fell;J. Macgregor
土壤中60 m深度处的S波速度通常在50 - 1200 m/s之间。这些速度可以与其他工程试验的结果相关联，例如标准贯入试验（SPT），以提供对浅层土材料的动态弹性特性的独立评估。通过垂直地震剪切波剖面法（VSSP），可以在套管井中获得可靠的土壤S波速度。垂直地震剪切波剖面法采用地面线性牵引SH波震源、紧贴孔壁的井下多分量地震检波器，以及涉及源极化反转的特殊现场程序，这些程序旨在增强SH波并帮助识别SH波。地震荷载作用下冲积物的液化评价可分别使用标准贯入试验和标准贯入试验进行。当直接S波穿过冲积物和折射S波从陡倾基岩界面在相同时间到达时，可以使用折射解释技术来解决解释问题。从所罗门群岛一个坝址获得的S波速度表明，该坝址的桑迪砾石主要处于中等密度状态，而不是SPT预期的密度状态。VSSP试验表明，在该地区可能发生的典型地震荷载下，这些材料可能会发生液化。
S-wave velocities in soils to depths of 60 m typically range from 50 to 1200 m/s. These velocities may be correlated with the results of other engineering tests, such as the standard penetration test (SPT), in order to provide an independent assessment of the dynamic elastic properties of shallow earth materials. Reliable S-wave velocities in soils may be obtained in cased boreholes by vertical seismic shear-wave profiling (VSSP), which employs a surface linear traction SH-wave seismic source, downhole multi-component geophones pneumatically packed against the hole wall, and special field procedures involving reversal of the source polarization, which are designed to enhance SH waves and assist their identification. Liquefaction assessment of alluvial materials under earthquake loading may be made independently using both SPT and VSSP. The problems of interpretation when both direct S waves travelling through the alluvial material and refracted S waves arising from the steeply dipping bedrock interface arrive at similar times can be resolved using refraction interpretation techniques. The S-wave velocities obtained from a dam site in the Solomon Islands suggested that the sandy gravels at the site were mainly in a medium dense state, not in a dense state as was expected from the SPT. The VSSP tests indicated that these materials may be subject to liquefaction under typical earthquake loadings likely to occur in the region.