黄土丘陵区边坡动力响应及震陷变形分析方法  

Dynamic response of slopes in hilly regions of loess and analysis method for their seismic subsidence deformation

作　　者：张彬 邵帅[1,2] 邵生俊 魏军政[3] ZHANG Bin;SHAO Shuai;SHAO Shengjun;WEI Junzheng(Institute of Geotechnical Engineering,Xi'an University of Technology,Xi'an 710048,China;Shaanxi Provincial Key Laboratory of Loess Mechanics and Engineering,Xi'an 710048,China;China Railway First Survey and Design Institute Group Co.,Ltd.,Xi'an 710043,China)

机构地区：[1]西安理工大学岩土工程研究所,陕西西安710048 [2]陕西省黄土力学与工程重点实验室,陕西西安710048 [3]中铁第一勘察设计院集团有限公司,陕西西安710043

出　　处：《岩土工程学报》2023年第4期869-875,共7页Chinese Journal of Geotechnical Engineering

基　　金：国家自然科学基金青年基金项目(52108342);陕西省自然科学基础研究计划-引汉济渭联合基金项目(2019JLP-21,2019JLZ-13);陕西省水利科技计划项目(2021slkj-12)。

摘　　要：黄土丘陵区易发生震陷型边坡失稳。通过动力离心模型试验和有限差分非线性动力分析方法研究地震时黄土边坡的动力响应及变形机制,探究了地震作用下概化黄土边坡的加速度及位移响应,提出了基于动单剪试验条件下黄土震陷系数经验公式及黄土场地震陷量估算方法,并应用于黄土边坡震陷变形计算。结果表明:黄土边坡对地震荷载具有放大效应,加速度放大系数沿高程呈非线性增大,且坡面动力放大效应大于坡体内部;边坡的震陷量与土层厚度关系密切,土层震陷系数随高程呈对数式增加;地震作用下黄土边坡的破坏形式是水平滑移变形与竖向震陷变形双向耦合的结果,震陷变形表现显著,边坡向临空面滑动,坡顶张拉裂隙和坡面错位裂隙大量发育,震陷沉降不均导致坡面形成错位阶梯。The hilly region of loess is prone to slope instability of seismic subsidence.Through the dynamic centrifugal model tests and the finite difference nonlinear dynamic analysis methods,the dynamic response and deformation mechanism of loess slopes under earthquakes are studied.The acceleration and displacement responses of the generalized loess slopes under earthquakes are explored.The empirical formula for the seismic subsidence coefficient of loess and the method for estimating the seismic subsidence of loess field are proposed based on the dynamic single shear tests,and they are also used to calculate the seismic subsidence of loess slopes.The results show that the loess slope has a magnification effect on the seismic loads,the acceleration magnification coefficient increases nonlinearly along the elevation,and the dynamic magnification effects of the slope surface are greater than those inside the slope.The seismic subsidence of the slope is closely related to the thickness of the soil layer.The seismic subsidence coefficient increases logarithmically with elevation.The failure form of loess slopes under earthquakes is the result of the two-way coupling of horizontal sliding deformation and vertical seismic subsidence deformation.The tensile fissures at the top of the slope and the dislocation fissures on the slope surface are widely developed,and the uneven settlement of the seismic subsidence leads to the formation of dislocation steps on the slope surface.

关 键 词：黄土边坡 动力离心模型试验 数值模拟 震陷 

分 类 号：TU433[建筑科学—岩土工程]