G318林芝—波密段斜坡地震动力响应及失稳机理  

Seismic Dynamic Response and Instability Mechanism of Slopes in Nyingchi-Bome Section of G318 Highway,Tibet

作　　者：武小菲[1] 王鹰[2,3] 叶唐进[2,3] 杨忠 江宇[2] 

机构地区：[1]西南交通大学土木工程学院,四川成都610031 [2]西藏大学工学院,西藏拉萨850000 [3]西南交通大学地球科学与环境工程学院,四川成都610031 [4]广西交通规划勘察设计研究院有限公司,广西南宁530002

出　　处：《西南交通大学学报》2017年第3期571-577,共7页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金资助项目(41462012);陕西省引汉济渭工程科技资助项目(YHJW-KY-007)

摘　　要：斜坡地层结构及地震动力响应是斜坡失稳破坏的重要因素.为进一步研究斜坡地震动力响应的差异性及地震动力响应规律,以G318林芝—波密段典型斜坡中的四类地层结构斜坡为原型,利用FLAC3D建立斜坡数值分析模型,通过在坡面及坡体设置监测点,输入Kobe地震波,对监测点的应变、水平位移及加速度等动力响应进行分析研究.结果表明:土层-岩层斜坡的坡面PGA(peak ground acceleration,PGA)放大系数随高度增加而增大,且在一定高度存在极值;坡体PGA放大系数与坡高呈线性增加,且千枚岩斜坡PGA放大系数更大,最大可达10.7;岩土接触带两侧,土层与岩层的水平位移差异明显,两者至少相差一个数量级,导致岩土接触带两侧介质变形不协调,这是土层-岩层斜坡在岩土接触带发生滑动的主要原因;不同土层斜坡的水平位移及PGA放大系数也有很大不同,且土层-岩层地层结构斜坡的失稳破坏程度主要受土层类型的控制.Strata structures and dynamic responses of slopes are significant factors in slope failures. In order to elucidate the dynamic response differences and dynamic response patterns of slopes with different stratum structures, a numerical simulation model of slope with Kobe seismic wave is established in FLAC 3D to analyze typical slopes of four types of strata structures in the Nyingchi-Bome section of G 318 highway, Tibet. Through this model, dynamic responses of strain, horizontal displacement and acceleration at the monitoring points located in different parts of slopes （ on slope surface and in slope body） are calculated and analyzed under the Kobe seismic wave. Results show that in the soil-rock slopes, the amplification factor of peak ground acceleration （ PGA ） on the slope surface increases with slope height and reaches a maximum at a certain height. The P G A amplification factor of the slope body increases linearly with slope height, with amaximum value of 10. 7, and is bigger in phyllitic slopes than other type of slopes. T he horizontal displacements of slopes on both sides of the rock-soil contact zone show great differences between soil and rock, even to nearly one order of magnitude. The deformation inconsistency caused by horizontal displacement is the primary reason for sliding in the rock-soil contact zone. Moreover, the horizontal displacement and P G A amplification factors for different soil slopes are obviously different, and the instability of soil-rock slopes is chiefly controlled by soil textures.

关 键 词：斜坡 地震动力响应 地层结构 数值模拟 

分 类 号：P642.22[天文地球—工程地质学]