倾斜入射地震波作用下边坡动力响应特征研究

发布时间：2018-03-24 19:10

本文选题：倾斜入射　切入点：边坡　出处：《长安大学》2017年硕士论文

【摘要】：考虑实际场地中地震波的入射角度影响,本研究基于FLAC3D大型数值分析方法,建立了数值分析中地震波倾斜入射的实现方法,并且建立了三种具有不同坡角的边坡数值计算模型,坡角分别为30°、45°、和60°,选取El Centro作为激励地震波,对地震波入射角对边坡的动力响应影响特征进行了研究。本文的研究主要取得了以下一些结论:(1)利用FLAC3D计算程序的人工边界力学条件,通过边界分解和边坡内部波场分解,可以实现在边坡动力响应数值计算中模型底部地震波的倾斜入射。(2)边坡的加速度响应研究表明,对于坡角为30°的边坡,随着入射角度的增大,坡顶的加速度放大系数出现轻微的先增大后降低的趋势;对于45°边坡和60°边坡而言,随着入射角度的增大坡顶的加速度放大系数逐渐增大,倾斜入射下的边坡坡顶加速度放大系数远大于垂直入射下的坡顶加速度放大系数;倾斜入射情况坡顶的加速度放大系数最大值均明显大于3,因此,入射角度对边坡加速度响应的影响不能忽视。(3)边坡坡面位移研究结果表明入射角度对边坡坡面的影响亦不容忽视,具体表现为:对于坡角30°的边坡,当入射角为30°时坡面的水平向位移残余值稍大于垂直入射情况,两者均明显小于入射角为10°和20°时的边坡坡面位移;对于坡角45°的边坡,随着入射角度的增大坡面的水平向残余变形逐渐增大。对于坡角60°的边坡,当地震波的强度较大时,坡顶的位移随着入射角度的增大而增大,当地震波强度较小时,坡顶的位移随着入射角度的增大先增大后减小。(4)坡体内部应力状态研究表明对于坡角为30°的边坡,坡体内部的应力状态十分复杂;对于坡角为45°的边坡,当入射角为10°时主要体现为剪应力状态,而张拉应力状态单元仅仅出现在坡面附近,当入射角达到20°和30°时,坡面附近大量单元均体现出剪应力+张拉应力状态;对于坡角为60°的边坡,当地震波入射角为10°和20°时,此时在坡面附近,尤其是坡角位置,出现了大量的张拉应力状态单元,当入射角为30°时,坡体内部的单元应力状态主要体现为剪应力状态。
[Abstract]:Considering the incident angle of seismic wave in the actual field effect, based on the FLAC3D method for the analysis of large value, based on the numerical analysis of inclined seismic wave method, and establishes three models with different slope numerical slope angle, slope angle was 30 degrees, 45 degrees, and 60 degrees from El Centro as the excitation of seismic wave, the seismic wave incident angle of slope dynamic response influence characteristics were studied. This thesis mainly achieved the following conclusions: (1) the artificial boundary condition of mechanical calculation program using FLAC3D, the boundary slope internal wave field decomposition and decomposition, can be achieved in the oblique incidence model at the bottom of the earthquake wave numerical calculation of slope dynamic response. (2) the acceleration response of the slope research shows that for the slope angle is 30 degrees, with the incident angle increases, the slope acceleration amplification coefficient slightly first Then decreased; for 45 degrees and 60 degrees slope slope, as the incident angle increases the slope acceleration amplification coefficient increases, the slope slope under inclined incident acceleration amplification coefficient is much larger than the vertical incidence of the top acceleration amplification coefficient; oblique incident case the slope acceleration amplification coefficient maximum value was significantly greater than 3 therefore, the angle of incidence, can not ignore the effect of slope acceleration response. (3) the results of slope displacement studies show that the effect of incident angle on slope also can not be ignored, the specific performance: the slope angle of 30 degrees, when the incident angle is 30 degrees slope horizontal displacement of residual value is slightly larger than the vertical incidence the situation, both were significantly less than the incident angle for slope displacement of 10 degrees and 20 degrees; for the slope angle of 45 degrees, with the increasing incident angle slope of the horizontal residual deformation by Gradually increase. For the slope angle of 60 degrees, the strength of the local wave is larger, the slope displacement increases with the increase of the incident angle, the local wave intensity was low, the slope displacement increases with the incident angle increases first and then decreases. (4) the slope stress state for slope angle for study 30 degrees, the slope stress state is very complex; the slope angle is 45 degrees, when the incident angle is 10 degrees is mainly reflected in the shear stress, and the tensile stress state unit only appear in the slope near, when the incident angle is 20 degrees and 30 degrees, near the slope a large number of units are reflected in the shear stress and tensile stress state; the slope angle is 60 degrees, when the earthquake wave incident angle is 10 degrees and 20 degrees, at this point in the slope near the slope angle, especially the position, there are a lot of tension stress state unit, when the incident angle is 30 the degree of the slope, single The state of the stress is mainly reflected in the state of shear stress.

【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU435

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