含反倾软弱夹层斜坡动力变形破坏特征及响应规律的大型振动台试验研究

发布时间：2019-06-03 14:22

【摘要】：地震是诱发斜坡变形、失稳、破坏的一个重要因素,而斜坡中的软弱夹层因其工程地质特殊性对斜坡的动力稳定性起着至关重要的作用。为了研究地震作用下含反倾软弱夹层斜坡的动力变形破坏特征及响应规律,本文在前人大量振动台试验研究的基础上,提出含反倾软弱夹层斜坡的简化概念模型,借助大型振动台试验研究手段,通过观测和记录模型试验过程中的变形破坏现象,收集斜坡模型沿高程分布的各个监测点的加速度动力响应数据来分析和总结该类斜坡的动力变形破坏特征和响应规律。通过试验研究主要得到以下几点成果:(1)地震动作用下含反倾软弱夹层斜坡的变形破坏特征及加速度动力响应规律与地震波的类型、频率、加载方向、激振强度(振幅)有关,同时还与坡体高程、坡体位置(坡面和坡内)以及斜坡所含软弱夹层的厚度大小等因素有关。(2)含反倾软弱夹层的斜坡在强震作用下的破坏方式为“震裂-散体崩落”型破坏,斜坡的坡面近水平裂缝起主要的控制作用,并且该类斜坡具有沿坡面裂缝呈带状散体崩落的特点。该类型斜坡的变形破坏集中在软弱夹层以上,坡体的中上部,这与坡面水平加速度在该部位被显著放大有关。当地震波振幅较低时,该类型斜坡不会发生较大的变形破坏,而它的变形破坏主要是由较高振幅的水平向地震波作用所引起的。(3)“尖峰现象”:含反倾软弱夹层斜坡坡面X向加速度动力响应沿高程的变化规律受输入波振幅大小的影响。当振幅值较低时,斜坡坡面X向加速度动力响应一般随高程的增加呈非线性增大,并在坡顶位置达到最大值,越接近坡顶,响应值增长的幅度也越大。当输入地震波的振幅值高于一定值后,斜坡坡面X向加速度动力响应并不在坡顶位置达到最大值,它会在斜坡坡面的中上部位产生最大响应值,出现本文所述的“尖峰现象”。(4)反倾软弱夹层的影响:①斜坡所含反倾软弱夹层越厚,斜坡产生变形破坏的位置越高,夹层的消能作用越强,斜坡的破坏范围、程度越小。②斜坡的PGA放大系数沿高程的增长速率一般在夹层处有所降低,其中坡面Z向PGA放大系数降幅最大。③斜坡坡内的加速度动力响应受夹层厚度变化的影响较坡面小。在软弱夹层以上部位,相同高程位置的斜坡加速度动力响应水平一般随软弱夹层厚度的增大而减小。夹层以下部位,坡面的Z向加速度动力响应水平最易受夹层厚度的影响,在汶川波作用下,夹层越厚,坡面Z向加速度动力响应值一般越大。④斜坡所含反倾软弱夹层的夹层厚度影响“尖峰现象”出现的坡面位置和该位置的加速度动力响应值的大小。软弱夹层厚度越大,出现“尖峰现象”的坡面位置越低,在该位置所对应的加速度动力响应值也越小。(5)含反倾软弱夹层的斜坡在强震作用下的变形破坏与斜坡坡面X向的加速度动力响应规律密切相关。软弱夹层厚度通过影响斜坡坡面X向加速度动力响应规律来影响斜坡发生变形破坏的位置。斜坡坡面X向加速度动力响应出现“尖峰现象”的高程位置与斜坡集中发生变形破坏的高程位置一致。斜坡所含软弱夹层的厚度越大,坡面X向加速度动力响应出现“尖峰现象”的位置越低,斜坡发生变形破坏的位置也越低。
[Abstract]:The earthquake is an important factor to induce the deformation, instability and failure of the slope, and the soft interlayer in the slope plays an important role in the dynamic stability of the slope due to the particularity of the engineering geology. In order to study the dynamic deformation and failure characteristics and the response of the inclined soft-bed slope under the action of earthquake, this paper puts forward a simplified conceptual model of an anti-roll soft sandwich slope based on the research of a large number of vibration table tests, and by means of the large-scale vibration table test, By observing and recording the deformation and failure phenomena in the model test, the acceleration dynamic response data of each monitoring point along the elevation distribution of the slope model is collected to analyze and summarize the dynamic deformation failure characteristic and response rule of the slope. The results of the experiment are as follows: (1) The deformation and failure characteristic of the slope with the anti-roll and weak interlayer under the action of ground motion and the dynamic response of the acceleration are related to the type, frequency, loading direction and excitation intensity (amplitude) of the seismic wave, and at the same time, it is also related to the elevation of the slope, The position of the slope (in the slope and the slope) and the thickness of the soft interlayer contained in the slope are related to the factors. (2) The failure mode of the slope with the anti-roll soft interlayer is the "spalling-dispersion caving" type failure under the action of strong earthquake, and the slope surface of the slope is mainly controlled by the horizontal crack, and the slope has the characteristics of being caving in the form of a strip-shaped dispersion along the slope surface. The deformation and destruction of this type of slope are concentrated above the soft interlayer and the upper part of the slope, which is related to the horizontal acceleration of the slope at this part. When the amplitude of the seismic wave is low, the slope of the type does not cause a large deformation and damage, and the deformation and failure of the slope are mainly caused by the horizontal directional wave action of the higher amplitude. (3) "spike phenomenon": The change law of the acceleration power response along the elevation of the slope surface with the anti-roll soft interlayer slope is affected by the amplitude of the input wave. When the amplitude value is low, the response of the slope surface X to the acceleration is generally nonlinear with the increase of the elevation, and the maximum value is reached at the top of the slope, and the higher the response value increases. When the amplitude value of the input seismic wave is above a certain value, the response of the slope surface X to the acceleration power does not reach the maximum value at the top of the slope, and the maximum response value is generated at the upper part of the slope surface, and the "spike phenomenon" described herein is present. (4) The effect of the anti-roll soft interlayer: the thicker the anti-roll soft interlayer contained in the slope, the higher the deformation of the slope, the stronger the energy dissipation effect of the interlayer, and the smaller the extent of the failure of the slope. The growth rate of the PGA amplification factor along the elevation along the elevation is generally lower at the interlayer, with the slope Z being the largest in the PGA amplification factor. The dynamic response of the acceleration in the slope of the slope is less affected by the change of the thickness of the interlayer. In the above part, the dynamic response level of the slope at the same elevation is generally decreased with the increase of the thickness of the soft interlayer. In the following parts of the interlayer, the Z-direction acceleration dynamic response level of the slope surface is most affected by the interlayer thickness, and under the effect of the Wenchuan wave, the thicker the interlayer, the greater the response response value of the surface Z to the acceleration. The interlayer thickness of the anti-roll soft interlayer contained in the top slope affects the slope position at which the "spike phenomenon" appears and the magnitude of the acceleration power response value of the position. The larger the thickness of the weak interlayer, the lower the slope position of the "spike phenomenon", and the smaller the response value of the acceleration force corresponding to the position. (5) The deformation of the slope with the anti-roll soft interlayer is closely related to the acceleration dynamic response law of the slope surface X under the action of strong earthquake. The thickness of the soft interlayer is affected by the dynamic response of the slope surface X to the acceleration, and the deformation of the slope is affected by the deformation of the slope. The elevation position of the "spike phenomenon" of the slope surface X to the acceleration power response is the same as the elevation position where the deformation of the slope concentration occurs. The larger the thickness of the soft interlayer contained in the slope, the lower the position of the slope X toward the acceleration power response, and the lower the deformation of the slope.
【学位授予单位】：成都理工大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：P642.27

【参考文献】