单一均质土覆盖层厚度对地表峰值加速度和反应谱平台值的影响*
文 雯1,2,宋廷苏2,王 珏2

(1.中国科学技术大学 地球和空间科学学院,安徽 合肥 230026; 2.云南省地震局,云南 昆明 650224)

覆盖层厚度; 峰值加速度; 反应谱平台值; 放大倍数

Effects of the Thickness of Overburden Layer with Signal Homogeneous Soil on Peak Acceleration of Ground Motions and Platform Value of the Acceleration Response Spectrum
WEN Wen1,2,SONG Ting-su2,WANG Jue2

(1. School of Earth and Space Sciences,University of Science and Technology of China,Hefei 230026,Anhui,China)(2. Earthquake Administration of Yunnan Province,Kunming 650224,Yunnan,China)

thickness of overburden layer; peak accelerations; platform value of acceleration response spectrum; amplification factor

备注

选择粘土、粉土、砂土、砾石4类土场地构造了140个单一均质土剖面,输入峰值分别为50、100、150、200、300 Gal的各3条人工合成地震动时程,使用一维等效线性波动法,进行了土层地表地震反应计算,并对计算得到的地表峰值加速度和反应谱平台值做了统计分析和讨论。结果 表明:不同土类地表峰值加速度和反应谱平台值随覆盖层增大达到最大值的厚度不同; 不同幅值的基底输入,不同土类的覆盖层情况下,地表峰值加速度相对于基岩值加速度的放大倍数并不具有规律性,同是Ⅱ类场地,中软和中硬场地土条件下放大倍数的差异也是明显的。

We build 140 single homogeneous soil profiles by using four types of soil,such as clay,silt,sand and gravel. Then using one-dimensional equivalent linear wave method,we calculate the seismic response of soil surface when inputting 3 time histories of synthetic ground motion with the peak of 50,100,150,200,300 Gal,and make a statistical analysis of calculated surface peak acceleration,platform value of the acceleration response spectrum. The results show that the surface peak acceleration,platform value of the acceleration response spectrum of different soil increase with thickness of overburden layer,then gradually decreased after reaching the peak. The thickness corresponding to the maximum peak is different. When inputting the time histories of synthetic ground motion with different peak or under condition of overburden layer with different soil,amplification factor of surface peak acceleration is less regularity than that of bedrock peak acceleration. The difference of amplification factor between the medium soft site and medium hard site which are in the same site typeⅡ is obvious.