Measurement of Liquefaction Ground Failure Resulting from the 1989 Loma Prieta Earthquake

该项目是美国国家科学基金会/美国地质勘探局在国家减少地震危害方案（NEHRP）下的倡议的一部分，目的是调查1989年10月17日洛马普列塔地震的影响。这次地震在旧金山湾区的许多地方造成了液化。液化是一种非常具有破坏性的土壤破坏形式，在1906年的旧金山地震和1989年的洛马普里塔地震中都造成了相当大的破坏。目前用于确定土壤沉积物的液化阻力的技术采用间接方法，将土壤穿透阻力和剪切波速与液化势相关联。​本研究计划的目的是研究一种替代技术，该技术可以更直接地测量土壤沉积物的液化潜力，即通过直接测量受到剪切应变时土壤孔隙压力的变化。这是通过使用剪切叶片来实现的。这个CSU（科罗拉多州立大学）压电片测量叶片快速旋转过程中孔隙压力的瞬时变化。本研究计划的目的是通过对旧金山湾区在洛马普里塔地震期间液化的地点进行系统的研究调查，应用CSU压电片来识别易液化的材料。预计这些信息将大大增加综合岩土工程调查，以收集自洛马普里塔地震以来进行的类似数据。

This project is part of the NSF/USGS initiative within the National Earthquake Hazard Reduction Program (NEHRP) to investigate the effects of the Loma Prieta earthquake of 17 October 1989. This earthquake caused liquefaction to occur at many sites in the San Francisco Bay area. Liquefaction, a very damaging form of soil failure, caused considerable damage during both the 1906 San Francisco and the 1989 Loma Prieta earthquakes. Current techniques for determining the liquefaction resistance of a soil deposit utilize an indirect method by correlating the soil penetration resistance and shear wave velocity with the liquefaction potential. The purpose of this research program is to study an alternative technique which gives a more direct measure of the potential for a soil deposit to liquefy, namely through a direct in-situ measurement of the change in soil pore pressure when subjected to shear strain. This is achieved by using a shear vane. This CSU (Colorado State University) Piezovane measures instantaneous changes in pore pressure during rapid rotation of the vane. The objective of this research program is to apply the CSU Piezovane to identify the material susceptible to liquefaction, by conducting a systematic research investigation of sites in the San Francisco Bay area that liquefied during the Loma Prieta earthquake. It is expected that this information will add significantly to the comprehensive geotechnical investigations to gather similar data that have been performed since the Loma Prieta earthquake.