000018664 001__ 18664
000018664 005__ 20170118182235.0
000018664 04107 $$aeng
000018664 046__ $$k2017-01-09
000018664 100__ $$aHara, Masahiro
000018664 24500 $$aSeismic Waveforms At Engineering Bedrocks Beneath Lifelines Suffered By Liquefaction in the 2011 Off the Pacific Coast of Tohoku Earthquake

000018664 24630 $$n16.$$pProceedings of the 16th World Conference on Earthquake Engineering
000018664 260__ $$b
000018664 506__ $$arestricted
000018664 520__ $$2eng$$aIn the 2011 off the Pacific coast of Tohoku earthquake (hereinafter the Tohoku earthquake), buried pipes for water supply, water treatments and telecommunication networks were severely damaged due to severe ground motions and induced liquefaction. Physical damage of buried pipes caused the functional disruption of associated lifeline facilities. In order to clarify the mechanism of the damage by combined actions of severe ground motions and liquefactions, first, we performed series of analyses on the seismic wave propagation in the Tohoku and Kanto areas in the Tohoku earthquake and revealed the trends of seismic waveforms in the affected regions by severe liquefaction: Hitachinaka City and Kamisu City in Ibaraki Prefecture, and Mihama in Chiba City. The synthetic waveforms at engineering bedrocks were computed using the finite difference method with fourth-order spatial and second-order temporal discretization proposed by Aoi and Fujiwara (1999) Second, we focused onto the occurrence of liquefaction at two sites: an inherently liquefiable site (HOR2) and relatively nonliquefiable site (HOR1) in Kamisu City, in which the affected sewer pipes are distributed, based on effective stress analyses using one synthetic waveform and three observed waveforms near the associated liquefied areas in the Tohoku earthquake. For the HOR2 site subjected to the synthetic waveform which wave amplitude at the engineering bedrock shows more than 0.5 m/s and 1.0 m/s2 with the abundance of about 3.0 s long-period components, but that is a relatively smaller amplitude level, the excess pore water pressure ratio gradually increases to the liquefaction criterion of 97% with the long duration of about 100 s excitation. In contrast, for the HOR1 site subjected to observed waveforms with the less long-period components but long duration of more than 100 s showing a relatively larger intensity of about 4.0 m/s2 after the main shocks, the excess pore water pressure ratio also reaches gradually and exceed the liquefaction level. Therefore, the input acceleration to the engineering bedrock with the rich long-period component of more than about 3.0 s and the long duration of more than about 100 s could gradually induce the liquefaction for an inherently liquefiable ground surface such as the Kamisu HOR2 site. From the other aspect, the input acceleration with the long duration of about 100 s after the main shocks showing the maximum intensity of about 4.0 m/s2 also could induce the liquefaction for a relatively non-liquefiable ground surface such as the Kamisu HOR1 site.

000018664 540__ $$aText je chráněný podle autorského zákona č. 121/2000 Sb.
000018664 653__ $$athe 2011 off the Pacific coast of Tohoku earthquake, sewer pipes, liquefaction, effective stress analysis

000018664 7112_ $$a16th World Conference on Earthquake Engineering$$cSantiago (CL)$$d2017-01-09 / 2017-01-13$$gWCEE16
000018664 720__ $$aHara, Masahiro$$iShoji, Gaku
000018664 8560_ $$ffischerc@itam.cas.cz
000018664 8564_ $$s6306003$$uhttps://invenio.itam.cas.cz/record/18664/files/1945.pdf$$yOriginal version of the author's contribution as presented on USB, paper 1945.
000018664 962__ $$r16048
000018664 980__ $$aPAPER