CAJ | 학술논문

目前我国建筑工程抗震设计规范中对于工程场地条件的判断依据主要是地表以下20 m 深度范围内土层的等效剪切波速,简称V S20。相比之下,国外应用较广的是地表以下30 m 深度范围内的等效剪切波速,简称V S30。这种差别导致国内科研工作者在应用国外的地震工程、工程抗震模型时经常遇到对场地条件描述不准确的困难。为了解决这个问题,本文根据147个四川、甘肃地区国家强震动台站20 m 左右深度的钻孔剪切波速数据,利用延拓方法、场地分类统计方法以及基于地形特征的V S30估计方法研究各台站V S30与 V S20的经验关系,对比发现基于速度梯度延拓的结果最为可取。参考国际上通用的 Geomatrix Classification 场地分类标准,最终得到四川、甘肃地区各类场地的平均V S30,此结果可以为缺乏钻孔数据的工程场地的V S30估计提供参考。
목전아국건축공정항진설계규범중대우공정장지조건적판단의거주요시지표이하20 m 심도범위내토층적등효전절파속,간칭V S20。상비지하,국외응용교엄적시지표이하30 m 심도범위내적등효전절파속,간칭V S30。저충차별도치국내과연공작자재응용국외적지진공정、공정항진모형시경상우도대장지조건묘술불준학적곤난。위료해결저개문제,본문근거147개사천、감숙지구국가강진동태참20 m 좌우심도적찬공전절파속수거,이용연탁방법、장지분류통계방법이급기우지형특정적V S30고계방법연구각태참V S30여 V S20적경험관계,대비발현기우속도제도연탁적결과최위가취。삼고국제상통용적 Geomatrix Classification 장지분류표준,최종득도사천、감숙지구각류장지적평균V S30,차결과가이위결핍찬공수거적공정장지적V S30고계제공삼고。
At present,Chinese seismic design codes for engineering projects classify site conditions primarily by their equivalent shear wave velocity at a depth of 20 m below the surface,which is referred to as V S20 .However,the parameter widely used abroad in seismic design codes is the e-quivalent shear wave velocity at a depth of 30 m below the surface,VS30 .This non-standardized parameter has led to inaccurate site condition descriptions when foreign models for earthquake en-gineering or seismic resistance are applied to Chinese engineering projects.Several methods have been used in an attempt to estimate VS30 from site profiles with 20 m-deep boreholes for strong motion stations located in the Sichuan and Gansu Provinces.These estimation methods include:extrapolation (constant and gradient),Geomatrix site classification correlation via shear-wave ve-locity,and remote sensing (terrain and topography).In this study,gradient extrapolation was the preferred estimation method for sites with shear-wave velocity profile data.When combined with Geomatrix site classification,the average VS30 for each site was derived from 147 estimated VS30 .Thus,gradient extrapolation followed by Geomatrix site classification can be used to assign a VS30 to a site without 30 m-deep borehole data,unifying global engineering design codes.