Site Characterization for Soil Liquefaction Susceptibility Using Geotomography

液化引起的地面破坏是地震中造成破坏的主要原因。减少这种损害的一个重要步骤是通过对与超孔隙压力发展相关的土壤特性进行现场测量来确定易受液化影响的地点。现有的场址调查方法无法完全描述一个场址的特征，因为测量只在离散的地点进行；土壤性质的空间变异性必须通过其他方法来推断。该项目的第一阶段的目标是开发和实施地震地质层析成像，以获得易液化地点的更完整特征。在地震地质层析成像中，用大量地震波穿过一块土体，测量初始切线剪切模量（用于液化敏感性评价的参数）的垂直和横向变化。第二阶段的目标是在南卡罗来纳州查尔斯顿的一个地点应用地震地质层析成像，以便与传统的场地表征技术，如标准贯入试验（SPT）和锥贯入试验（CPT）进行比较。已知这个地区存在易液化的土壤。

Liquefaction-induced ground failures are a major cause of damage during earthquakes. An important step in minimizing this damage is to identify sites that are susceptible to liquefaction by making in situ measurements of soil properties related to excess pore pressure development. Existing methods of site investigation are unable to characterize a site completely because measurements are made at discrete locations only; the spatial variability of soil properties has to be inferred by other methods. The objective of the first phase of this project is to develop and implement seismic geotomography to obtain a more complete characterization of sites susceptible to liquefaction. In seismic geotomography, a mass of soil is traversed by a large number of seismic waves to measure the vertical and lateral variability of the initial tangent shear modulus (a parameter used for liquefaction susceptibility evaluation). The objective of the second phase is to apply seismic geotomography at a site in the Charleston, South Carolina, seismic zone so as to compare geotomography with conventional site characterization techniques, such as the standard penetration test (SPT) and the cone penetration test (CPT). Soils susceptible to liquefaction are known to exist in this area.