Identification of shear strength and seismic coefficient by back analyzing surficial slides in the 2004 Mid-Niigata prefecture earthquake

Landslides ◽  
2018 ◽  
Vol 15 (11) ◽  
pp. 2255-2266 ◽  
Author(s):  
Surangani Bandara ◽  
Satoru Ohtsuka ◽  
Yutaka Fukumoto
2021 ◽  
Vol 13 (15) ◽  
pp. 8647
Author(s):  
Dongli Li ◽  
Miaojun Sun ◽  
Echuan Yan ◽  
Tao Yang

The method of pseudo-static analysis has been widely used to perform seismic slope stability, in which a seismic coefficient is used to represent the earthquake shaking effect. However, it is important but difficult to select the magnitude of seismic coefficients, which are inevitably subjected to different levels of uncertainties. This paper aimed to study the influences of seismic coefficient uncertainties on pseudo-static slope stability from the perspective of probabilistic sensitivity analysis. The deterministic critical slope height was estimated by the method of upper-bound limit analysis with the method of pseudo-static analysis. The soil shear strength parameters, the slope geometrical parameters (including slope inclinations, slope heights, and the slope widths), the horizontal seismic acceleration coefficient, and the unit weight of soil masses were considered as random variables. The influences of their uncertainty degrees, the correlation relations, and the distribution types of random variables on probabilistic density functions, failure probabilities, and sensitivity analysis were discussed. It was shown that the uncertainty degrees greatly impact the probability density distributions of critical slope heights, the computed failure probabilities, and Sobol’ index, and the horizontal seismic coefficient was the second most important variable compared to the soil shear strength parameters.


2002 ◽  
Vol 27 ◽  
Author(s):  
K. Aoyama ◽  
P. Bhattarai ◽  
M. Fukuda ◽  
J. Oku ◽  
T. Sakai

Fence-type defensive structures are very common on highway hillsides in Japan. They are constructed to protect the highway mainly from snow avalanche. Initially, these structures behave well. However, as the time lapses, the foundation of these well designed structures weakens and collapses. The situation is further aggravated by the static load of accumulated thick snow cover behind them. As mudstone is the dominant rock type in the Niigata Prefecture, it is a challenging task for geotechnical engineers to cope with such a severe geo-environmental problem. Although the mudstone exhibits a high strength while it is dry and fresh, it becomes quite unstable after sometime. When it comes in contact with water and atmosphere repeatedly, it starts weathering. Consequently, its shear strength is reduced and cannot resist the imposed shear stress and moment, and ultimately fails. For the laboratory investigation, mudstone blocks of various sizes were collected from the two typical mudstone areas: the Matsunoyama area and Nagaoka area in the Niigata Prefecture. These samples were sub merged and then dried alternately for several cycles. The particle size analysis of the weathered material showed that the proportion of fine particles increased with the degree of weathering. The laboratory tests of these samples exhibited a decrease in shear strength with an increasing degree of saturation. The periodic swelling and contraction of the clay fraction leads to volume change of foundation inducing its further weathering.


1992 ◽  
Vol 05 (03) ◽  
pp. 100-103 ◽  
Author(s):  
G. Jean ◽  
J. K. Roush ◽  
R. M. DeBowes ◽  
E. M. Gaughan ◽  
J. Kirpensteijn

SummaryThe holding power and holding power per mm bone width of 4.5 mm and 5.5 mm cortical and 6.5 mm cancellous orthopaedic screws were obtained by tensile load-to-failure studies in excised metacarpal and metatarsal bones of young female Holstein calves. Holding power and holding power per mm bone width of 6.5 mm orthopaedic screws were significantly greater than those of 4.5 and 5.5 mm orthopaedic screws in the diaphysis and metaphysis. Significant differences were not detected between holding power and holding power per mm bone width of 4.5 and 5.5 mm orthopaedic screws. The holding power was not different between metacarpi and metatarsi. The limiting factor in all tests of holding power was the shear strength of the bone. We found that 6.5 mm orthopaedic screws have the greatest holding power in the metacarpal and metatarsal bones of young calves.This study compares the holding power of 4.5 mm and 5.5 mm cortical and 6.5 mm cancellous orthopaedic screws in excised metacarpal and metatarsal bones from young female Holstein calves. We found that 6.5 mm orthopaedic screws have the greatest holding power.


2020 ◽  
Author(s):  
Iván A. Contreras ◽  
Jed D. Greenwood ◽  
Aaron T. Grosser

2020 ◽  
Vol 9 (4) ◽  
pp. e31942727
Author(s):  
João Gabriel Missia da Silva ◽  
Pedro Nicó de Medeiros ◽  
Denise Ransolin Soranso ◽  
Vinicius Peixoto Tinti ◽  
José Tarcísio da Silva Oliveira ◽  
...  

The aim of this study was to evaluate the influence of anatomical characteristics on the adhesion performance of Vatairea sp., Paulownia sp., Aspidosperma populifolium and Tectona grandis wood. Specimens for anatomical, physical and mechanical analyzes were produced from tangentially oriented boards. The treatments were joint glued from pieces of the same anatomical orientation (radial and tangential), evaluated for shear strength and glue line failure. The Vatairea sp wood had the highest specific gravity (0.74 g cm-3) and the Paulownia sp (0.34 g cm-3) wood was smaller. Aspidosperma populifolium species showed the highest shear strength in the glue line in the tangential and radial faces. The anatomical variables with higher influence on the wood adhesion process were pith ray cells and especially fibers that exhibit the greatest correlation with the shear strength of the glue line.


PCI Journal ◽  
1960 ◽  
Vol 5 (2) ◽  
pp. 40-49
Author(s):  
M. A. So zen

2015 ◽  
Vol 10 (1) ◽  
pp. 31-38
Author(s):  
Ildikó Buocz ◽  
Nikoletta Rozgonyi-Boissinot ◽  
Ákos Török

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