P波斜入射形成的动应力路径及影响因素分析（英文）

发布时间：2018-08-07 16:28

【摘要】：目的:研究P波斜入射下的地基动应力路径,探讨其影响因素和可能变化范围,为进一步研究斜入射地震波作用下场地动力响应奠定理论基础。创新点:1.从数学上证明斜入射P波在任一深度的地基中形成的应力路径在剪应力分量(偏差正应力-水平剪应力)组成的平面中为一个斜椭圆;2.分析了P波入射角、土体泊松比和单位波长深度对斜椭圆应力路径形状与大小的影响。方法:1.基于半无限弹性空间的地震波传播理论,考虑地震波在自由界面的反射,推导土体中任一深度处由P波斜入射产生的动应力,并表示成由剪应力分量组成的平面下的应力路径(公式(9))及该应力路径的特征参数表达式(公式(A12)~(A14));2.通过控制变量法,分析参数敏感性(图7、9、10和12)。结论:1.虽然证实P波斜入射引起的应力路径为斜椭圆形式,但在地基深度、入射波频率和波速的特定组合下,斜椭圆仍可从斜线一直变化到圆形,形式较为多样化;2.P波斜入射角度在30?~60?时引起的动偏应力幅最大,最大可达同等条件下其它入射角产生的动应力幅的2倍以上;3.斜入射角大于45?后,斜椭圆路径形状几乎不随入射角改变,在研究范围内以竖直扁椭圆形为主;4.土体饱和度大于70%时,泊松比的变化对土体斜椭圆路径形状影响不大,但动应力幅随泊松比增大而显著降低。
[Abstract]:Aim: to study the dynamic stress path of foundation under oblique incidence of P-wave, and to discuss its influencing factors and possible range of variation, so as to lay a theoretical foundation for the further study of the dynamic response of the ground under the action of oblique incident seismic wave. The innovation point is 1: 1. It is mathematically proved that the stress path formed by the oblique incident P wave in the foundation of any depth is an oblique ellipse in the plane composed of the shear stress component (deviation normal stress and horizontal shear stress). The effects of incident angle of P-wave, Poisson's ratio of soil mass and depth of unit wavelength on the shape and size of oblique ellipse stress path are analyzed. Method 1: 1. Based on the theory of seismic wave propagation in semi-infinite elastic space, considering the reflection of seismic wave at the free interface, the dynamic stress caused by the oblique incidence of P-wave at any depth in soil is derived. It is also expressed as the stress path (formula (9) and the characteristic parameter expression (formula (A12) ~ (A14) of the stress path under the plane composed of the shear stress component (A12) ~ (A14). The sensitivity of parameters was analyzed by the control variable method (figs. 7, 9, 10 and 12). Conclusion 1. Although it is confirmed that the stress path caused by the oblique incidence of P wave is obliquely elliptical, the oblique ellipse can change from diagonal to circular under the specific combination of depth of foundation, frequency of incident wave and velocity of wave. The amplitude of dynamic deflection stress is the largest, and the maximum amplitude is more than 2 times of that of other angles of incidence under the same condition, and the amplitude of dynamic deflection stress is more than 3 times of that of other angles of incidence under the same conditions. Angle of incidence greater than 45? After that, the path shape of oblique ellipse almost does not change with the incident angle, and the vertical flat ellipse is dominant in the range of study. When the saturation of soil is larger than 70, the change of Poisson's ratio has little effect on the shape of oblique elliptical path of soil, but the amplitude of dynamic stress decreases with the increase of Poisson's ratio.
【作者单位】： Institute
【基金】：Project supported by the National Natural Science Foundation of China(Nos.51178427 and 51278451) the National Basic Research Program(973 Program)of China(No.2014CB047005)
【分类号】：TU43

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