Oshima, Ryoji

A Study of the Evaluation Method for Embankment Collapse Risk

Abstract eng:
Nowadays, existing earth structures which consist of the important infrastructural network must be needed to endure large earthquake, as well as reinforced concrete structures, metal structures. Therefore, new earth structures have been aseismic designed, but many earth structures which presents the service of Japan City Railway Network are not aseismic designed because most of them were constructed in old age. In order to improve the problems, we must consider the appropriate retrofitting strategy, so that we need the method for evaluation collapse risk of earth structures by earthquake. We investigated and analyzed the property of damaged and no-damaged railway earth structures which had experienced severe seismic excitation. Those were investigated for categorizing with height, slope gradient, geomorphologic classification, and so on. And the influence of each property was analyzed by the assumption point and verification with the database. According to the results of investigated data, the difference between damaged and no-damaged embankment has a strong correlation to geomorphologic classification, environment around the site, height of embankment, damaged experience, and so on. Furthermore, we calculated the deformation of damaged and no-damaged railway embankments in 10 areas where severe damage had occurred. We used the Newmark method (modified circular slip surface analysis) for calculating the deformation. Calculating results revealed that the railway embankments of which yielding intensity is less than 0.3 were severely damaged. In contrast, those of which the yielding intensity is over than 0.3 was severely in case the groundwater level was high, and the fine fraction content of lower embankment materials or that of upper bearing strata were less than 35%, and bearing strata contained thick organic soil layer. Being based on the investigated data and the calculation results, this paper suggests the method of evaluation collapse risk for earth structures by real phenomena caused by the 2011 off the Pacific coast of Tohoku Earthquake.

Contributors:

Fujiwara, Torajiro

Conference Title:

Proceedings of the 16th World Conference on Earthquake Engineering

Conference Title:

16th World Conference on Earthquake Engineering

Conference Venue:

Santiago (CL)

Conference Dates:

2017-01-09 / 2017-01-13

Rights:

Text je chráněný podle autorského zákona č. 121/2000 Sb.