【作者】 何刘；

【导师】 吴光；

【作者基本信息】 西南交通大学 ， 地质工程， 2013， 博士

【摘要】 交通工程边坡在地震作用下的行为特征研究,是近年来研究的热点问题。随着国家工程建设的投入,我国大量线路工程将会不可避免的穿越地震活跃区,科研人员将会遇到大量复杂边坡问题,而边坡问题将会伴随着工程建设的进行而变得日益突出。本学位论文在全面研究现代交通线路工程的各类边坡破坏模式的基础上,利用室内物理模型试验和数值模拟算等手段开展了边坡工程地质问题动力学的理论研究,为交通工程边坡治理防护和交通工程边坡地质灾害预测评价提供了动力学理论依据。主要研究成果如下：(1)按照机械设计原理和结构动力学原理,设计了二维单向振动试验台。利用位移传感器和动态采集系统对模型箱的位移时程曲线进行了采集,并且通过结构动力学理论计算,获取了理想状态下单向振动的位移时程曲线,通过两条曲线对比发现,振动试验台整体性能稳定,能够满足小型荷载的振动试验。(2)边坡坡面形态对边坡的变形破坏有着直接的影响；凸面边坡由于滑动体质量大,所以在振动力施加时能够瞬问发生整体的变形破坏,而凹面边坡由于滑体质量较小,在振动力作用下容易造成滑体的分段下滑,位于滑体下部的块体先行下滑,进而带动整个滑体的滑动破坏,由此造成的宏观现象是凹面边坡坡面的裂隙要早于边坡坡顶的裂隙产生,而凸面边坡则与此相反。凹凸组合面边坡的变形破坏受坡面上凸起部分的影响。(3)边坡的变形破坏程度以及滑动面倾角与边坡坡面的凹凸程度直接相关；边坡凹陷或凸出程度越强烈的边坡,振动试验结束后其坡顶剩余的部分就越少；同时分析发现,滑动面滑床倾角随着边坡坡面凹陷或者凸出程度的减缓而逐渐增大。(4)边坡坡面形态对坡面加速度分布有直接影响；边坡加速度放大系数在坡而凹陷和凸起区域达到局部最大,并且逐步向外减小,在同等情况下,凸而坡坡面的加速度放大效应要强于凹面坡坡面放大效应。在凹凸组合面边坡中,加速度放大效应也在边坡坡面凹陷处和凸起处达到最大。加速度在边坡内部都有随着坡高的增高而增高的趋势,而且处于同一高程的边坡坡面放大效应趋势要大于边坡内部,但不同坡面形态边坡坡体内部加速度分布并未出现不同规律,说明边坡坡面形态对边坡内部加速度的分布影响较小。(5)通过对层状岩石边坡物理模型试验发现,受结构面的影响,顺层模型边坡的变形破坏主要是沿着固定层面的滑动破坏,反倾向模型边坡的变形破坏主要是以崩塌体的形式破坏。(6)高程位置较高的隧道口由于滑体将其包含其中而容易造成隧道口的整体破坏,而高程较低的隧道口由于滑塌体堆积而容易造成隧道洞口堵塞。(7)结构面参数对边坡动力响应规律的影响较大；结构面刚度较小的边坡下部坡体的三量峰值较小,而上部坡体三量峰值较大；结构面越靠近边坡坡顶,结构面上部坡体的三量放大系数就越高；随着结构面倾角的增加,顺层结构面边坡加速度放大系数随之增大,反倾向结构面边坡加速度放大系数随之减小,顺层结构面边坡加速度放大系数整体大于反倾向结构面边坡加速度放大系数；结构面厚度较小的边坡其动力响应较为强烈,结构面厚度较大的边坡动力响应较弱；不同结构面连通率的边坡,加速度峰值的差异较为明显,在结构面位置处,连通率较大的结构面放大效应较强。(8)通过总结太平隧道出口边坡工程地震安全性分析发现,太平隧道出口边坡受结构面的影响较大,在地震来临时,结构面切割块体会受到拉张剪切应力作用而发生整体和单个块体的下滑,但是由于隧道洞口位置适中,滑体滑动面位于隧道洞口以上,并且滑体滑落后不会出现堵塞洞口的现象,这一规律给隧道出口边坡震后的迅速通车提供了可贵的先前条件。整体而言,太平隧道出口边坡选址较为可观。更多还原

【Abstract】 Researches on behavioral characteristics of traffic engineering slopes under seismic actions have been the hot issue in recent years. With the investment in national engineering construction, large numbers of line projects in China will inevitably run through seismically active areas, as a result, scientific researchers will face lots of complicated slope problems, and slope problems will stand out increasingly along with the proceeding of engineering construction. In this paper, theoretical researches on dynamics of slope engineering geological problems were performed by laboratory physical model tests, numerical simulation algorithm and other methods based on comprehensive research on various slope failure modes of modern transport line projects, thus providing theoretical dynamic basis for control and protection of traffic engineering slopes as well as prediction and evaluation of geological hazards of traffic engineering slopes. Major research achievements are as follows:(1) A2D one-way vibration test bench is designed according to mechanical design principles and structural dynamic principles. The displacement-time curve of a model box is acquired using a displacement sensor and a dynamic acquisition system, and the displacement-time curve in one-way vibration under ideal conditions is acquired by theoretical calculation of structural dynamics, and comparison between the two curves shows that the vibration test bench has stable overall performance and can meet vibration tests of small loads.(2) Slope forms have direct impact on deformation and failure of slopes; for convex slopes, overall deformation and failure can occur instantaneously in case of application of vibration force due to large sliding masses, for concave slopes, segmental sliding of sliding masses easily occurs under the action of vibration force due to small sliding masses, masses below sliding masses slide, resulting in overall sliding failure of the sliding masses, the resulting macro phenomena are that surface fissure occurs earlier than top fissure for concave slopes, on the contrary, top fissure occurs earlier than surface fissure for convex slopes. Deformation and failure of combined concave and convex slopes are impacted by projections of slopes.(3) Deformation and failure of slopes and dip angles of sliding surfaces are directly related to concave and convex extent of slope surfaces; the stronger the concave or convex extent of the slope is, the less the remaining slope crest is after vibration tests; and analysis reveals that dip angles of sliding beds of sliding surfaces increase gradually with the decline of the concave or convex extent of the slope surfaces.(4) Slope forms have direct impact on the distribution of slope acceleration; the maximum slope acceleration amplification coefficient appears at local concave and convex slope areas, and gradually decreases outwards, under the same circumstances, the acceleration magnification effects of convex slopes are stronger than the amplification effects of concave slopes. With regard to combined concave and convex slopes, the maximum acceleration magnification effects occur at depression and projection of slopes. Acceleration tends to increase with the increase of slope height with regard to the same slope, and the amplification effects of slopes at the same height are larger than those in slopes, however, internal acceleration distribution of slopes of different slope forms is the same, indicating that slope forms have small impact on internal acceleration distribution of slopes.(5) Physical model tests on stratified rock slopes reveal that deformation and failure of bedding model slopes are mainly sliding failure along fixed bedding surfaces, and deformation and failure of anti-dip model slopes are mainly failure of avalanche masses.(6) Tunnel portals at higher elevation are prone to overall failure as they are included in sliding masses, and tunnel portals at lower elevation are easily blocked due to slump accumulation.(7) Parameters of structural planes have great impact on dynamic response of slopes; lower slopes of slopes with small structural plane stiffness have smaller peak values of the three factors, and upper slopes have larger peak values of the three factors; the closer the structural planes is to the slope crest, the larger the amplification coefficient of the three factors of upper slopes of the structural planes is; with the increase of dip angles of structural planes, the slope acceleration amplification coefficient of bedding structural planes increases, and the slope acceleration amplification coefficient of anti-dip structural planes decreases, the slope acceleration amplification coefficient of bedding structural planes is integrally larger than the slope acceleration amplification coefficient of anti-dip structural planes. Slopes with smaller structural plane thickness have stronger dynamic response, and slopes with larger structural plane thickness have weaker dynamic response; slopes with different connectivity rates of structural planes have obvious differences in acceleration peak values, and structural planes with larger connectivity rates have stronger amplification effects at structural planes. (8) By summarizing the analysis on seismic safety of the slope project at Taiping Tunnel portal, the slope at Taiping Tunnel portal is greatly impacted by structural planes, in an earthquake, cutting blocks of structural planes will slide in overall and individual blocks under the action of tensile stress and shear stress. However, as the tunnel portal is located in a moderate position, sliding surfaces of sliding masses are above the tunnel portal, and the portal will not be blocked by the sliding masses, this pattern provides good prerequisite conditions for quick traffic operation after earthquake of slopes at tunnel portals. Generally speaking, the slope site of Taiping Tunnel portal is appreciable.更多还原