浅层SH反射波法和多道瞬态面波法 进行联合工程勘察的讨论   总被引：2，自引：1，他引：1  

仇恒永  王治华  王书增  夏学礼 《物探与化探》2008,32(4):451-454

针对目前单一工程物探方法调查浅部地质结构的局限性,提出采用弹性波法勘察中研究浅部地质结构的SH波反射勘察和多道瞬态面波法勘察这2种有效手段进行联合勘探,提高其可靠性和精度,并给出了3个实例,指出了在数据采集和处理时应注意的问题。  相似文献   

圆弧状沉积盆地与软土单覆盖层出平面地表运动对比   总被引：2，自引：0，他引：2  

袁晓铭  李雨润  孙锐 《地震工程与工程振动》2002,22(4):16-21

采用解析方法，通过圆弧状沉积盆地与同样参数的软土均匀单覆盖层的对比，研究沉积盆地对平面SH波二维散射效应和其出平面地表运动。数值对比结果表明：（1）波垂直入射时盆地中央地表位移幅值反应，其随频率变化形式与软土单覆盖层的地表运动有较强的对应性，且此时单覆盖层地表位移幅值为其下降；（2）盆地的二维散射效应特点显著波的汇聚作用使盆地中的地表运动显著放大，总体上较软土单覆盖层的地表位移幅值要大，其频域内的最大反应则明显大于单覆盖层情况，但最大反应在盆地表面出现的位置依赖于入射波角度、盆地深宽比和盆地的软硬程度；（3）沉积盆地中地表位移运动有强烈扭转效应，且随盆地变软和入射波频率增高而增强。  相似文献   

任意圆弧形凸起地形中隧洞对入射平面SH波的影响   总被引：10，自引：2，他引：10       下载免费PDF全文

梁建文  罗昊  Vincent W.Lee 《地震学报》2004,26(5):495-508

借助辅助函数的思想， 采用波函数展开法给出了圆弧形凸起地形中隧洞对入射平面SH波影响问题的一个解析解．数值结果表明，凸起地形中隧洞的存在以及隧洞大小，对凸起地形表面运动，以及凸起地形中的隧洞的动应力集中均具有显著影响．   相似文献   

SH Wave Propagation in Viscoelastic Media     

Daley  P.F.  Krebes  E.S. 《Studia Geophysica et Geodaetica》2004,48(3):563-587

When comparing solutions for the propagation of SH waves in plane parallel layered elastic and viscoelastic (anelastic) media, one of the first things that becomes apparent is that in the elastic case the location of the saddle points required to obtain a high frequency approximation are located on the real p axis. This is true of the branch points also. In a viscoelastic medium this is not typical. The saddle point corresponding to an arrival lies in the first quadrant of the complex p-plane as do the branch points. Additionally, in the elastic case the saddle point and branch points lie on a straight line drawn through the origin (the positive real axis in the complex p-plane), while in the viscoelastic case this is generally not the case and the saddle point and branch points lie in such a manner as to indicate the degree of their complex values.In this paper simple SH reflected and transmitted particle displacement arrivals due to a point torque source at the surface in a viscoelastic medium composed of a layer over a half space will be considered. The path of steepest descent defining the saddle point in the first quadrant will be parameterized in terms of a real variable and the high frequency solutions and intermediate analytic results obtained will be used to formulate more specific constraints and observations regarding saddle point location relative to branch point locations in the complex p-plane.As saddle point determination for an arrival is, in general, the solution of a non-linear equation in two unknowns (the real and imaginary parts of the complex saddle point p ₀), which must be solved numerically, the use of analytical methods for investigating this problem type is somewhat limited.Numerical experimentation using well documented solution methods, such as Newton's method, was undertaken and some observations were made. Although fairly basic, they did provide for the design of algorithms for the computation of synthetic traces that displayed more efficient convergence and accuracy than those previously employed. This was the primary motivation for this work and the results from the SH problem may be used with minimal modifications to address the more complicated subject of coupled P-SV wave propagation in viscoelastic media.Another reason for revisiting a problem that has received some attention in the literature was to approach it in a fairly comprehensive manner so that a number of specific observations may be made regarding the location of the saddle point in the complex p-plane and to incorporate these into computer software. These have been found to result in more efficient algorithms for the SH wave propagation and a significant enhancement of the comparable software in the P-SV problem.  相似文献   

SH波对无限介质土中衬砌结构的动应力集中     

周香莲  周光明 《岩土力学》2004,25(Z2):366-368

运用复变函数法和保角映射法对无限介质土中的衬砌结构进行分析.通过引入两个势函数将弹性介质的控制方程解耦成两个Helmholtz方程.利用所得势函数的通解,得到无限土介质和衬砌结构的位移和应力的表达式,利用无限介质与衬砌结构之间的连续性条件和衬砌结构内边界上的边界条件,可确定波函数展开式中的末知系数,并给出动应力集中系数的数值结果.  相似文献   

黑龙江饶河枕状玄武岩地质、地球化学特征及其构造属性   总被引：1，自引：0，他引：1  

何松  孙晓猛  张旭庆  万阔  郑涵  李多姿 《世界地质》2016,35(4):942-954

为了确定饶河玄武岩的构造属性,在野外地质观察的基础上,对玄武岩进行岩石学研究和地球化学分析。玄武岩具有典型的枕状构造、淬冷边、中空骸晶和鬣刺结构等特征,反映其形成于海底喷发环境。化学分析样品具有高TiO_2、MgO和低Al_2O_3、CaO、P_2O_5、K_2O等特征,富集大离子亲石元素(Rb、Sr和Ba),微量元素蛛网图呈向上隆起形态,稀土元素配分曲线为右倾型(∑LREE/∑HREE为5.8~6.5),无δEu异常(0.92~0.97),表明样品具有洋岛玄武岩特征。主量和微量元素构造环境判别图指示了样品形成于洋岛或板内环境。样品与亚速尔型和夏威夷型洋岛玄武岩地球化学特征对比,表现出明显的夏威夷型洋岛玄武岩特征。岩石源区分析揭示出岩浆具有地幔热柱起源,并有先期交代地幔熔体的混入,岩浆源区还受壳幔循环的影响。研究表明,饶河枕状玄武岩为夏威夷型洋岛玄武岩,形成于洋壳消减阶段的洋中脊轴外板内喷发环境,为饶河地区存在成熟的洋盆提供直接证据。结合区域研究成果,认为饶河地区经历了古太平洋板块的扩张、洋中脊轴外板内地幔柱上涌、洋壳俯冲消减以及向佳木斯地块仰冲增生的构造演化过程。  相似文献   

Application of the weighted residual method to diffraction by 2-D canyons of arbitrary shape: I. Incident SH waves   总被引：1，自引：0，他引：1  

Vincent W. Lee  Xiaoyun Wu 《Soil Dynamics and Earthquake Engineering》1994,13(5)

A solution for the two-dimensional scattering and diffraction of plane SH waves by canyons of arbitrary shape in an elastic half space is presented. The wave field for arbitrary geometry in this paper is computed numerically by the method of weighted residues (moment method). The wave displacement field computed by the present residual method for the case of a semi-circular canyon was shown to agree analytically and numerically with that computed by the exact closed form series solution. The same observations about ground amplifications, their dependence on frequencies and orientations of the incident waves, can be stated here for canyons of arbitrary shape as previously made for circular canyons.  相似文献   

圆弧型沉积盆地对平面SH波的散射   总被引：19，自引：0，他引：19  

袁晓铭  廖振鹏 《华南地震》1995,15(2):1-8

采用波函数展开方法给出圆弧型沉积盆地对面ＳＨ波二维散射问题的封闭级数解答。利用外域Ｇｒａｆ加法公式将解答归结为无穷代数方程组的求解。通过截断计算得到解答的数值结果，并通过连续条件的满足程度检验了截断计算的精度。将本文结果已有的近似解析解进行比较，指出了近似解答的误差来源和适用范围。给出一些典型算例说明盆地深度比对地震动的复杂作用。  相似文献   

台湾费丛峡谷对强地面运动的影响研究──利用单台资料及2．5维SH混合方法     

温联星  姚振兴 《地球物理学报》1995,38(1):64-70

本文通过格林函数反褶积方法，由台湾峡谷附近的记录资料预测峡谷区的强地面运动的时程曲线．峡谷区的理论格林函数应用２．５维ＳＨ混合方法求解．通过格林函数反褶积方法得到的峡谷区费丛１及费丛２台的位移、速度、加速度和实际资料对比，取得了满意结果．计算结果表明，峡谷底部的峰值加速度相对峡谷边缘为最小；在靠近震中的一侧，峡谷的加速度的最大振幅相对比另一侧大．还给出了其余３个台的预测结果，研究了它们的加速度傅里叶谱和反应谱．  相似文献   

SH波入射下圆弧状沉积盆地地震反应瞬态解析解计算     

任朋  陈三红  张郁山 《震灾防御技术》2021,16(2):352-361

地震波散射问题的解析解是研究局部场地、地形、盆地等不规则地层结构对地震动参数放大效应影响的重要理论工具。现有解析解大部分在频域内给出，无法直接用于研究不规则地层结构对地震动峰值、反应谱等参数的放大效应。本文基于平面SH波入射下圆弧状沉积盆地动力响应宽频带稳态解析解，通过Fourier变换，获取瞬态响应解析解。基于此，研究El Centro波入射下，沉积盆地对地震动峰值加速度、峰值速度、峰值位移及不同周期反应谱的放大效应。研究结果表明，盆地宽度和深度、沉积介质波速、入射波角度等对盆地放大效应具有显著影响，地震动反应谱谱比最大值超过2.0，且宽度达10 km的较大型盆地对长周期地震动参数具有显著放大效应，对于位于该类盆地的超高层建筑、大型储液罐、大跨度桥梁等长周期结构，应充分考虑盆地对抗震设防参数的影响。  相似文献