Topographic Effects on the Seismic Coefficient and Earthquake-Induced Permanent Displacement of Earth Slopes

Earthquakes frequently induce landslides and other natural disasters that have a huge impact on human life and properties. In geotechnical engineering, evaluation of the seismic stability of earth slopes has been attracting great research interests. In this regard, the Newmark permanent displacement provides a simple yet effective index of slope co-seismic performance. Traditional Newmark method involves many assumptions and the displacement results thereby calculated are subjected to various degrees of uncertainty. In this paper, a modified rotational sliding block model considering depth-dependent shear strength and dynamic yield acceleration is established. The seismic critical slip surface is analysed through a pseudo-static approach, and the failure volume is larger than that in the static condition. The dynamic yield acceleration is updated by considering the instantaneous movement of the sliding mass in each time-step. The parametric sensitivity of soil shear strength, slope shape and Arias intensity to the permanent displacement is also analysed. The results show that the internal friction angle and the cohesion have equal effects on the permanent displacement. On a logarithmic scale, the displacement approximately linearly correlates with Arias intensity. Furthermore, the underlying uncertainty of the ground motion is introduced to obtain the probabilistic distribution of the seismic slope displacement. The uncertainty of earthquake details has considerable influence on the permanent displacement results.

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Semi-empirical relationships to assess the seismic performance of slopes from an updated version of the Italian seismic database

Bulletin of Earthquake Engineering ◽

10.1007/s10518-020-00937-6 ◽

2020 ◽

Vol 18 (14) ◽

pp. 6245-6281

Author(s):

D. Gaudio ◽

R. Rauseo ◽

L. Masini ◽

S. Rampello

Keyword(s):

Ground Motion ◽

Seismic Performance ◽

Permanent Displacement ◽

Empirical Relationships ◽

Site Specific ◽

Ground Motion Parameters ◽

Seismic Coefficient ◽

Motion Parameters ◽

Semi Empirical ◽

Parametric Integration

Abstract Seismic performance of slopes can be assessed through displacement-based procedures where earthquake-induced displacements are usually computed following Newmark-type calculations. These can be adopted to perform a parametric integration of earthquake records to evaluate permanent displacements for different slope characteristics and seismic input properties. Several semi-empirical relationships can be obtained for different purposes: obtaining site-specific displacement hazard curves following a fully-probabilistic approach, to assess the seismic risk associated with the slope; providing semi-empirical models within a deterministic framework, where the seismic-induced permanent displacement is compared with threshold values related to different levels of seismic performance; calibrating the seismic coefficient to be used in pseudo-static calculations, where a safety factor against limit conditions is computed. In this paper, semi-empirical relationships are obtained as a result of a parametric integration of an updated version of the Italian strong-motion database, that, in turn, is described and compared to older versions of the database and to well-known ground motion prediction equations. Permanent displacement is expressed as a function of either ground motion parameters, for a given yield seismic coefficient of the slope, or of both ground motion parameters and the seismic coefficient. The first are meant to be used as a tool to develop site-specific displacement hazard curves, while the last can be used to evaluate earthquake-induced slope displacements, as well as to calibrate the seismic coefficient to be used in a pseudo-static analysis. Influence of the vertical component of seismic motion on these semi-empirical relationships is also assessed.

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Simulation and Analysis of the Topographic Effects on Snow-Free Albedo over Rugged Terrain

Remote Sensing ◽

10.3390/rs10020278 ◽

2018 ◽

Vol 10 (2) ◽

pp. 278 ◽

Cited By ~ 13

Author(s):

Dalei Hao ◽

Jianguang Wen ◽

Qing Xiao ◽

Shengbiao Wu ◽

Xingwen Lin ◽

...

Keyword(s):

Topographic Effects ◽

Rugged Terrain

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Radiometric Corrections In Slant Range And Geocoded Sar Images Considering Topographic Effects

[Proceedings] IGARSS '92 International Geoscience and Remote Sensing Symposium ◽

10.1109/igarss.1992.576787 ◽

2005 ◽

Author(s):

E. Meier ◽

F. Holecz ◽

D. Ntiesch

Keyword(s):

Topographic Effects ◽

Sar Images ◽

Slant Range

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Topographic Effects on the Spatial Species Associations in Diverse Heterogeneous Tropical Evergreen Forests

Sustainability ◽

10.3390/su13052468 ◽

2021 ◽

Vol 13 (5) ◽

pp. 2468

Author(s):

Nguyen Hong Hai ◽

Yousef Erfanifard ◽

Van Bac Bui ◽

Trinh Hien Mai ◽

Any Mary Petritan ◽

...

Keyword(s):

Species Interactions ◽

Species Coexistence ◽

Spatial Scales ◽

Interspecific Interactions ◽

Spatial Association ◽

Topographic Effects ◽

Habitat Association ◽

Important Species ◽

Evergreen Forests ◽

Partial Overlap

Studying spatial patterns and habitat association of plant communities may provide understanding of the ecological mechanisms and processes that maintain species coexistence. To conduct assessments of correlation between community compositions and habitat association, we used data from two topographically different plots with 2 ha area in tropical evergreen forests with the variables recorded via grid systems of 10 × 10 m subplots in Northern-Central Vietnam. First, we tested the relationship between community composition and species diversity indices considering the topographical variables. We then assessed the interspecific interactions of 20 dominant plant species using the nearest-neighbor distribution function, Dij(r), and Ripley’s K-function, Kij(r). Based on the significant spatial association of species pairs, indices of interspecific interaction were calculated by the quantitative amounts of the summary statistics. The results showed that (i) community compositions were significantly influenced by the topographic variables and (ii) almost 50% significant pairs of species interactions were increased with increasing spatial scales up to 10–15 m, then declined and disappeared at scales of 30–40 m. Segregation and partial overlap were the dominant association types and disappeared at larger spatial scales. Spatial segregation, mixing, and partial overlap revealed the important species interactions in maintaining species coexistence under habitat heterogeneity in diverse forest communities.

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