摘要
采用间接边界积分方程法(indirect boundary integral equation method, IBIEM),分析了SH波入射下梯形河谷表面地震动特性和分布规律,研究了地震波斜入射角度、斜坡坡度、底宽以及场地剪切波速对场地地震动特性及非一致分布规律的影响机制,深入分析了不同剪切波速下河谷散射效应对地基截断边界地震动场的影响规律。结果表明,随着左侧斜入射角的增大,左侧斜坡放大效应逐渐增强,两岸地震动非一致分布特性越趋明显。左侧斜入射地震波,随着斜坡变缓,地形散射效应引起的放大区域逐渐向右扩展,两岸坡顶及坡脚地震动非一致性增强;随着底宽的增大,地形散射效应引起的放大区域逐渐由右扩展,坡脚相对位移对底宽变化敏感,两岸坡脚地震动非一致性增强;波速较小情况下,河谷散射效应显著,左侧坡顶位移峰值最大为右侧坡顶的1.45倍,两岸地震动非一致性明显。在截断边界输入地震动时,应充分考虑河谷地形散射效应,将自由场和散射场组成的总场作为输入,以获得合理的地震动输入。
Here, based on the indirect boundary integral equation method(IBIEM), trapezoidal valley surface ground motion characteristics and distribution laws under SH wave incidence were analyzed. Influence mechanisms of oblique incidence angle of seismic wave, slope gradient, bottom width and site shear wave velocity on site ground motion characteristics and non-uniform distribution law were studied. Influence laws of valley scattering effect under different shear wave velocities on seismic field at foundation truncated boundary were deeply analyzed. The results showed that with increase in left side oblique incidence angle, amplification effect of left side slope is gradually enhanced and the non-uniform distribution characteristics of ground motion on both banks are more obvious;for left side oblique incident seismic wave, when slope becomes gentle, amplification area caused by terrain scattering effect gradually expands to right, and the ground motion inconsistency at top and toe of slopes on both banks increases;with increase in bottom width, amplification area caused by terrain scattering effect gradually expands from right, relative displacement of slope toe is sensitive to change of bottom width, and the ground motion non-uniformity of slope toe on both banks increases;when SH wave velocity is smaller, scattering effect of valley is significant, the maximum displacement peak at left side slope top is 1.45 times that at right slope top, and the ground motion inconsistency between both banks is obvious;when truncating boundary input ground motion, scattering effect of valley terrain should be fully considered, and the total field composed of free field and scattering field is taken as input to obtain reasonable and accurate ground motion input.
作者
赵磊超
宋志强
王飞
刘云贺
张存慧
ZHAO Leichao;SONG Zhiqiang;WANG Fei;LIU Yunhe;ZHANG Cunhui(State Key Lab of Ecological Water Conservancy in Northwest Arid Area,Xi’an University of Technology,Xi’an 710048,China;Changjiang Institute of Survey,Planning,Design and Research,Co.,Ltd.,Wuhan 420100,China)
出处
《振动与冲击》
EI
CSCD
北大核心
2022年第23期109-118,128,共11页
Journal of Vibration and Shock
基金
国家自然科学基金重点项目(52039008)
国家自然科学基金(51779208,51479165)。
关键词
间接边界积分方程法(IBIEM)
河谷地形
SH波
非一致特性
散射效应
indirect boundary integral equation method(IBIEM)
valley topography
SH wave
non-uniform characteristics
scattering effect
