Collaborative Research: Shear Wave Velocity Profiling by SASW Method at Selected Strong-Motion Stations, Liquefaction Sites, and Sites of Building Damage: 1999 Turkey Earthquakes

1999年在土耳其发生的科凯利和杜兹地震在以下地点产生了重要的信息和数据：(L)记录到强烈地面运动的台站，(2)发生显著土壤液化的地点，以及(3)建筑物损坏差异很大的局部地区。研究这三类场地地震反应的一个关键变量是地基土的剪切刚度分布。犹他州立大学(USU)和德克萨斯大学奥斯汀分校(UTA)的研究人员将联合进行一项研究，利用实地进行的地震测量来确定每个类别中选定的地点的特征。总共将对大约20个地点进行调查。地震测量将被用来在场地的临界深度上开发小应变剪切模数剖面，有些是一维的，有些是二维的。剖面深度将从9米到60米不等，液化场地通常需要最浅的剖面，强震记录站需要最深的剖面。为了进行地震测量，将使用一种涉及瑞利型面波的非侵入性地震测试技术。这项技术被称为表面波频谱分析(SASW)测试。这种技术是非侵入性的，因为源和接收器都放置在地面上。在现场进行了面波频散(即以不同速度传播的不同波长的面波)的测量，并在实验室中使用正演模拟来评估场地的横波速度剖面。在过去的18年里，UTA的研究人员已经成功地在陆地上的岩土现场使用了SASW测试。在20世纪90年代的S期间，美国运输协会的研究人员在加利福尼亚州完成了对1989年洛马普里塔和1994年北岭地震所震动的液化场地、固体废物填埋场和强震动站的大量调查。在土耳其，这一经验将用于优化选定地点的概况分析。例如，一台将在强震现场附近当地租用的推土机将被用作深度剖面的来源。一种可在土耳其制造的轻量型震源将被用来描绘较浅的深度。拟议中的项目至关重要，因为它提供了受到科凯利和杜兹塞地震影响的重要地点的广泛剪切波速度表征。声表面波测试是评估横波速度剖面的最经济有效的方法。这项研究获得的剪切波速数据将与地震工程界和地震界共享，并将被证明对未来的研究项目非常有价值。

CMS-0085257BayThe 1999 Kocaeli and Duzce earthquakes in Turkey have generated important information and data at: (l) stations where strong ground motions were recorded, (2) sites where significant soil liquefaction occurred, and (3) localized areas with widely varying building damage. One key variable in investigating the earthquake response at these three types of sites is the shear stiffness profile of the foundation soils. A joint study will be conducted by researchers at Utah State University (USU) and the University of Texas at Austin (UTA) to characterize selected sites in each category using seismic measurements made in the field. A total of about 20 sites will be investigated. The seismic measurements will be used to develop small-strain shear modulus profiles, some one-dimensional and some two-dimensional, over critical depths at the sites. Profiling depths will range from 9 to 60 m, with liquefaction sites generally requiring the shallowest profiles and strong motion recording stations requiring the deepest profiles.To perform the seismic measurements, a non-intrusive seismic testing technique involving Rayleigh-type surface waves will be used. This technique is called spectral-analysis-of-surface-waves (SASW) testing. The technique is non-intrusive because both the source and receivers are placed on the ground surface. Measurement of surface wave dispersion (i.e. surface waves of differing wavelengths travelling at different velocities) is performed in the field and forward modeling is used in the laboratory to evaluate the shear wave velocity profile at the site. Researchers at UTA have been successfully using SASW testing at geotechnical sites on land for the past 18 years. During the 1990's, UTA researchers completed numerous investigations in California at liquefaction sites, solid-waste landfills, and strong motion stations shaken by the 1989 Loma Prieta and 1994 Northridge earthquakes. In Turkey, this previous experience will be used to optimize profiling at the selected sites. For instance, a bulldozer, which will be rented locally near the strong-motion sites, will be used as a source for deep profiling. A drop-weight source, which can be readily fabricated in Turkey, will be used in profiling the shallower depths.The proposed project is critical because it provides extensive shear wave velocity characterization of important sites shaken by the Kocaeli and Duzce earthquakes. SASW testing is the most cost-effective method for evaluating shear wave velocity profiles. The shear wave velocity data obtained from this study will be shared with the earthquake engineering and seismological communities and will prove invaluable to future research projects.