基于动三轴试验的砂土阻尼比确定方法对场地地震动参数的影响  

Effects of sand damping ratio determination methods induced from dynamic triaxial tests on ground motion parameters

作　　者：宋东松 刘红帅 赵帅 SONG Dongsong;LIU Hongshuai;ZHAO Shuai(Institute of Geotechnical Engineering,Hebei University,Baoding 071002,China;Hebei Excellent Earthquake Prevention Service Co.,Ltd.,Baoding 071028,China)

机构地区：[1]河北大学岩土工程研究所,河北保定071002 [2]河北极致地震预防服务有限公司,河北保定071028

出　　处：《地震工程与工程振动》2023年第6期194-202,共9页Earthquake Engineering and Engineering Dynamics

基　　金：中国地震局工程力学研究所基本科研业务费专项资助项目(2019EEEVL0202);河北省高等学校科学技术研究项目(ZD2020157);河北省自然科学基金项目(E2020201017)。

摘　　要：基于动三轴试验提出的砂土阻尼比确定方法有多种,但其对场地地震动参数影响的研究鲜有报道。为此,以福建标准砂(粒径0.10~0.25 mm)的试验结果为基础,采用规范方法、KUMAR方法、DAS方法、DOYGUN方法和互相关函数方法5种典型阻尼比确定方法给出相应的动剪切模量比和阻尼比;设计单层土场地和多层土场地2种典型工况,采用一维场地地震反应分析波动程序,计算给出场地地表加速度峰值和反应谱,定量评价相应的阻尼比确定方法对场地地表地震动参数的影响规律。结果表明:5种阻尼比确定方法得到的阻尼比对地表加速度峰值的影响程度随输入地震动加速度峰值的增大而不断增大,同时对多层土场地的影响明显高于单层土场地;采用5种方法确定的阻尼比计算的反应谱差异性在单层土场地时相对较小,而在多层土场地时有明显的差别;与规范方法相比,4种阻尼比确定方法计算反应谱的最大相对误差可达-35%。因此,有必要采用离心振动台试验结果进一步检验基于动三轴试验的砂土阻尼比确定方法的合理性,为场地地震反应分析提供可靠的阻尼比参数。There are various methods proposed from dynamic triaxial tests for determining the damping ratio of sand.But,the investigation about the effects of these methods on ground motion parameters of site is scare.Therefore,based on the test results of Fujian standard sand(particle size 0.10~0.25 mm),five typical damping ratio determination methods(canonical method,KUMAR method,DAS method,DOYGUN method and cross-correlation function method)are used to give the corresponding dynamic shear modulus ratio and damping ratio.Two typical working conditions for single-layer soil sites and multi-layer soil sites were designed,a one-dimensional seismic response analysis wave program to calculate the peak ground acceleration and response spectrum of the site was used,and the impact of the corresponding damping ratio determination method on the ground motion parameters of the site was quantitavely evaluated.The results show that the influence of the damping ratios obtained by the five damping ratio determination methods on the peak ground acceleration continuously increases with the increase of the input seismic acceleration peak,and the impact on multi-layer soil sites is significantly higher than that on single-layer soil sites.The difference in response spectra calculated using the damping ratios determined by five methods is relatively small in single-layer soil sites,while there is a significant difference in multi-layer soil sites.Compared with the standard method,the maximum relative error of the four damping ratio determination methods in calculating the response spectrum can reach-35%.Therefore,it is necessary to further verify the rationality of the sand dam ping ratio determination methods based on dynamic triaxial tests by using centrifuge tests results to provide reliable damping ratio parameters for seismic site response analysis.

关 键 词：砂土 阻尼比确定方法 地表加速度峰值 反应谱 场地地震反应 

分 类 号：TU4[建筑科学—土工工程]