Ground Motion at a Semi-Cylindrical Valley Partially Filled with a Crescent-Shaped Soil Layer Under Incident Plane SH Waves

2017 ◽  
Vol 11 (03) ◽  
pp. 1750007 ◽  
Author(s):  
Ning Zhang ◽  
Yufeng Gao ◽  
Denghui Dai
Keyword(s):  
Ground Motion ◽  
Soil Layer ◽  
Topographic Effects ◽  
Soil Amplification ◽  
Alluvial Valley ◽  
Sh Waves ◽  
Topographic Amplification ◽  
Incident Plane ◽  
Irregular Topography ◽  
Plane Sh Waves

To elucidate the ground motion amplification due to soil and topographic effects, an analytical formulation based on wavefunction expansion is derived for the scattering of plane SH waves by a semi-cylindrical valley partially filled with a crescent-shaped soil layer. The site responses consisting of both soil and topographic effects from the partially filled alluvial valley and the pure topographic contribution from the homogeneous valley of the same geometry are calculated and compared. It is found that the soil amplification effects are usually larger than the topographic amplification effects within the alluvial valley, while the topographic effects dominate the amplification pattern of ground motions outside the alluvial valley. Generally, the maximum soil amplification generally far outweighs the maximum topographic amplification. The material parameters and filling degree of the soil layer are found to affect the magnitude and the pattern of ground motion amplitude on the valley surface depending on the irregular topography, the frequency content and obliquity of the wave incidence.

scholarly journals Ground motion on alluvial valleys under incident plane SH waves

1991 ◽  
Vol 33 (2) ◽  
pp. 240-253 ◽  
Author(s):  
David L. Clements ◽  
Ashley Larsson
Keyword(s):  
Numerical Solution ◽  
Integral Equations ◽  
Ground Motion ◽  
Boundary Integral Equations ◽  
Layered Material ◽  
Boundary Integral ◽  
Alluvial Valley ◽  
Sh Waves ◽  
Incident Plane ◽  
Plane Sh Waves

AbstractThe scattering and diffraction of harmonic SH waves by an arbitrarily shaped alluvial valley in a layered material is considered. The problem is solved in terms of boundary integral equations which yield a numerical solution.

scholarly journals Soil-Structure Interaction in Transversely Isotropic Layered Media Subjected to Incident Plane SH Waves

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Zhenning Ba ◽  
Xi Gao
Keyword(s):  
Soil Structure ◽  
Soil Layer ◽  
Transversely Isotropic ◽  
Soil Structure Interaction ◽  
Rigid Foundation ◽  
Sh Waves ◽  
Soil Layers ◽  
Incident Plane ◽  
Input Motion ◽  
Plane Sh Waves

The dynamic soil-structure interaction (SSI) for incident plane SH waves is analyzed for a two-dimensional (2D) model of a shear wall on a rigid foundation by using the indirect boundary element method (IBEM). The rigid foundation utilized in this study is embedded in transversely isotropic (TI) soil layers over bedrock. The accuracy of the IBEM method is verified and analyzed by setting a semicylindrical, rigid foundation-shear wall structure system in the single TI soil layer and multiple TI soil layers over bedrock. This study shows that the TI characteristics of the site have a significant impact on the effective input motion and the superstructure response. In a single soil layer, the increase in the shear modulus ratio in the vertical and horizontal directions has a certain degree of amplified action on the effective input motion and the superstructure response. Simultaneously, the corresponding peak frequency of the response increases. In multiple soil layers, the changes in the effective input motion and the superstructure response are also affected by the TI characteristics of the soil layers, and the impact of this effect is related to the sequence of the layers.

Ground motion on alluvial valleys under incident plane SH waves

1979 ◽  
Vol 69 (4) ◽  
pp. 1107-1120
Author(s):  
Francisco J. Sánchez-Sesma ◽  
Jorge A. Esquivel
Keyword(s):  
Boundary Conditions ◽  
Least Squares ◽  
Ground Motion ◽  
Analytical Solutions ◽  
Line Source ◽  
Fredholm Integral Equations ◽  
Discretization Scheme ◽  
Sh Waves ◽  
Incident Plane ◽  
Plane Sh Waves

abstract A method is presented to compute the scattering and diffraction of harmonic SH waves by an arbitrarily shaped alluvial valley. The problem is formulated in terms of a system of Fredholm integral equations of the first kind with the integration paths outside the boundary. A discretization scheme using line source solutions is employed and the boundary conditions are satisfied in the least-squares sense. Numerical results for amplification spectra for different geometries are presented. Agreement with known analytical solutions is excellent.

Surface motion of a semi-cylindrical alluvial valley for incident plane SH waves

1971 ◽  
Vol 61 (6) ◽  
pp. 1755-1770 ◽  
Author(s):  
M. D. Trifunac
Keyword(s):  
Incidence Angle ◽  
Alluvial Valley ◽  
Sh Waves ◽  
Surface Motion ◽  
Wave Interference ◽  
Incident Plane ◽  
Wave Propagation Problem ◽  
Wave Patterns ◽  
Closed Form Analytical Solution ◽  
Plane Sh Waves

abstract The nature of surface motion in and around a semi-cylindrical alluvial valley is investigated for the case of incident plane SH waves. The closed-form analytical solution of this two-dimensional wave-propagation problem displays complicated wave-interference phenomena characterized by nearly-standing wave patterns, rapid changes in the ground-motion amplification along the free surface of the valley, and significant dependence of motion on the incidence angle of SH waves. Although simple, this model may qualitatively explain some vibrating characteristics of long and deep alluvial valleys.

Interaction of a shear wall with the soil for incident plane SH waves

1972 ◽  
Vol 62 (1) ◽  
pp. 63-83
Author(s):  
M. D. Trifunac
Keyword(s):  
Incidence Angle ◽  
Closed Form Solution ◽  
Shear Wall ◽  
Elastic Half Space ◽  
Form Solution ◽  
Angle Of Incidence ◽  
Sh Waves ◽  
Incident Plane ◽  
Interaction Equation ◽  
Plane Sh Waves

Abstract The closed-form solution of the dynamic interaction of a shear wall and the isotropic homogeneous and elastic half-space, previously studied only for vertically-incident SH waves, is generalized to any angle of incidence. It is shown that the interaction equation is independent of the incidence angle, while the surface-ground displacements heavily depend on it. For the two-dimensional model studied, it is demonstrated that disturbances generated by waves scattering and diffracting around the rigid foundation mass are not a local phenomenon but extend to large distances relative to the characteristic foundation length.

Torsional response of structures for SH waves: The case of hemispherical foundations

1976 ◽  
Vol 66 (1) ◽  
pp. 109-123
Author(s):  
J. E. Luco
Keyword(s):  
Closed Form Solution ◽  
Form Solution ◽  
Basic Step ◽  
Sh Waves ◽  
Torsional Response ◽  
Obliquely Incident ◽  
Incident Plane ◽  
Interaction Problem ◽  
Plane Sh Wave ◽  
Plane Sh Waves

abstract A study is made of the harmonic torsional response of an elastic structure placed on a rigid hemispherical foundation which is supported on an elastic medium and is subjected to the action of obliquely incident plane SH waves. As a basic step in the solution of the torsion interaction problem, a closed-form solution is obtained for the torsional response of a rigid hemispherical foundation excited externally by a harmonic torque and through the soil by an obliquely incident plane SH wave. Comparisons between the results for a hemispherical foundation with those for a circular plate allow the estimation of the effects that the embedment of the foundation has on the torsional response of the superstructure.

scholarly journals Seismic response analysis of loess site under far-field bedrock ground motion of the Wenchuan earthquake

PLoS ONE ◽  
2021 ◽  
Vol 16 (7) ◽  
pp. e0254871
Author(s):  
Tuo Chen
Keyword(s):  
Ground Motion ◽  
Seismic Waves ◽  
Linear Method ◽  
Soil Layer ◽  
Resonance Phenomenon ◽  
Amplification Coefficient ◽  
Response Analysis ◽  
Topographic Effects ◽  
Far Field ◽  
Short Period

In this paper, considering the far-field seismic input, an accelerogram recorded in the bedrock at Wuquan Mountain in Lanzhou city during the 2008 Wenchuan Ms8.0 earthquake was selected, and numerical dynamic analyses were conducted. The one-dimensional equivalent linear method was implemented to estimate the ground motion effects in the loess regions. Thereafter, slope topographic effects on ground motion were studied by applying the dynamic finite-element method. The results revealed the relationship between the PGA amplification coefficients and the soil layer thickness, which confirmed that the dynamic response of the sites had obvious nonlinear characteristics. The results also showed that there was an obvious difference in the dynamic magnification factor between the short-period and long-period structures. Moreover, it was found that the amplification coefficient of the observation point at the free surface was greater than the point inside the soil at the same depth, which mainly occurred in the upper slope. Through this study, the quantitative assessment of ground motion effects in loess regions can be approximately estimated, and the amplification mechanism of the far-field ground motion mechanism can be further explained. In addition to the refraction and reflection theory of seismic waves, the resonance phenomenon may help explain the slope topographic effect through spectrum analysis.

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