【作者】 高乐；

【导师】 言志信；

【作者基本信息】 兰州大学 ， 岩土工程， 2013， 硕士

【摘要】 我国是一个多山的国家,山地、高原和丘陵占国土面积的69%,这就从客观上决定了我国有大量的自然边坡。同时我国地处世界上两条最活跃的地震带之间,强震分布广,其中西部地区地震活动性强、频度高,近年来的地震活动表明我国地震活动正趋于活跃。地震作用下边坡的动力响应研究是边坡动力稳定分析的基础,近半个世纪以来,人们对边坡动力反应问题的研究,倾注了极大的热情,并取得了一些成绩,但研究对象多局限于均质概化模型边坡,研究程度较低。本文首先归纳总结了边坡动力响应方面的研究现状,接着针对顺层岩质边坡,使用FLAC3D软件模拟了二维顺层岩质边坡模型在双向耦合地震情况下的动力响应特征、三维顺层岩质边坡模型在双向耦合地震情况下的动力响应特征和三维顺层岩质边坡模型在三向耦合地震情况下的动力响应特征,分析了坡面的位移时程曲线,最大位移分布,PGA放大系数分布,取得了如下一些主要认识：1.二维顺层岩质边坡在双向耦合地震情况下的坡面位移的变化主要由X方向加速度控制,坡面上的位移时程变化和X方向加速度的峰值变化成对应关系；耦合地震作用下X方向最大位移增大了39.3%,说明耦合地震作用模拟比单纯的水平地震作用模拟更加接近实际情况,对岩土体的破坏效应更大；双向耦合地震情况下,随着av/aH的增大,坡面各点横向最大位移基本呈增大趋势,证明地震波产生的水平向与竖向拉裂耦合作用是触发边坡产生初期崩滑破坏的主控因素,竖向地震作用起了重要的破坏作用,而av/aH越大,破坏越剧烈,这也印证了许多地震工作者发现极震区竖向地震力起破坏作用的事实。2.三维边坡模型的动力响应特征有其作为三维体而独有的特点,特别是坡面长度(Z向)上的动力响应特征分布是二维边坡模型所不具有的,所以对于边坡的数值模型计算应该根据边坡的实际长度来建立三维模型,这样可以使模拟结果更加接近实际情况。3.三向耦合地震是最接近现实地震情况的模拟方式,在三向耦合地震作用下三维顺层岩质边坡模型的模拟结果最接近实际情况,不仅可以作为定性研究的结论,在一定程度上也可以作为定量分析的依据；坡面方向(Z向)动力响应特征值的不同分布也符合了现实中边坡的滑移存在先后顺序的情况。更多还原

【Abstract】 China is a mountainous country and mountain, plateau and hills accounts for69%of land area, so it objectively determines that there are plenty of natural slopes in our country. Meanwhile, our country is located between two of the most active earthquake zones, which makes earthquake distribution is wide and seismic activity is strong and frequency is high in the Middle Western region. And the seismic activity in recent years show that seismic activity in China is tend to be more active. Study on slope dynamic response under earthquake force is the basis of stability analysis of slope. Nearly half a century, reaearchers have poured nenormous enthusiasm into the dynamic response of slope and have made some achivment. But most of the research object modek is the relatively simple homogeneous slope, and the research degree of this problem at home and abroad is relatively low.This paper summarized the research status quo of the slope dynamic response, then the bedding rock slope is selected for the study direction. By using FLAC3D, author simulates the dynamic response characteristics of2D model of bedding rock slope under coupling vibration in two cases, the dynamic response characteristics of3D model of bedding rock slope under coupling vibration in two cases and the dynamic response characteristics of3D model of bedding rock slope under the condition of three-way coupling vibration. By analyzing of the slope surface displacement, time history curve of maximum displacement, and change of PGA amplification coefficient, author has made some major conclutions as follows:The change of slope surface displacement in the2D model of bedding rock slope under coupling vibration in two cases are mainly controlled by the level of the acceleration in X direction, and the slope displacement time history on the surface has a corresponding relationship with the peak value of acceleration of X direction. X direction maximum displacement under the coupling vibration increases by39.3%, which shows that coupling vibration effect is closer to actual situation and to the destruction of the rock mass effect is bigger than simple horizontal vibration simulation. Under coupling vibration in two case, all point slope lateral maximum displacement showed a trend of increase with the increase of the aV/aH, which proves slope body collapse is trigger by the effect of the coupling of horizontal and vertical tensile splitting seismic wave and the destruction of the vertical seismic action plays an important role. Meanwhile, the greater the aV/aH, the more severe damage, which confirms many workers’founds that the vertical seismic force play damage effect in magistoseismic area.The slope dynamic response characteristics of3D model has its unique characteristics as3D body, especially the distribution of the dynamic response characteristics along the slope length (Z-direction) dosen’t exist in2D slope model. Therefore, the numerical model calculation for slope should build3D model according to the actual length of the slope. As a result, we can make the simulation results closer to actual situation.Three-way coupling vibration is the simulation methods which is most close to the real situation of the earthquake and simulation results of3D bedding rock slope model under three-way coupling vibration is quite close to the actual situation, which not only can be used as a qualitative conclusion, to a certain extent, can also be used as the basis for quantitative. Different distribution of dynamic response characteristics along slope direction (Z-direction) also conforms to the reality of the slope slip points successively.更多还原