Numeričko ispitivanje seizmičkog ponašanja željezničkog nasipa u hladnim područjima

• Published in: Journal of the Croatian Association of Civil Engineers
• Main Authors: Tuo, Chen, Yanhu, Mu, Jianzhou, Wang, Junwei, Zhang
• Format: Article in Journal/Newspaper
• Language: English; Croatian
• Published: 2021
• Subjects: permafrost; dinamičko ponašanje; seizmički odziv; područje plastičnosti; permafrost. dynamic behaviour. seismic response. plastic zone
• Online Access: https://hrcak.srce.hr/262815; https://hrcak.srce.hr/file/382085; https://hrcak.srce.hr/file/382084

U ovom radu provedene su iscrpne rasprave i analize primjenom numeričkih tehnika, a s ciljem da se posve ispita seizmičko ponašanje željezničkog nasipa Qinghai-Tibet. Točnije, provedena je analiza jednodimenzionalnog ekvivalentnog linearnog odziva tla u područjima permafrosta. Na temelju toga, seizmički odziv tipičnog željezničkog nasipa dalje se ispitao nelinearnim dinamičkim proračunom metodom konačnih elemenata. To je rezultiralo određivanjem nelinearnog ponašanja tla na području permafrosta (stalno smrznuto tlo), a raspravljalo se o dinamičkom ubrzanju, brzini i pomaku nasipa te se predvidjela približna kvantitativna ocjena. Rezultati upućuju na to da dinamički odziv nasipa ima izrazito nelinearna svojstva. Koeficijent vršnog ubrzanja tla na kruni nasipa veći je nego na prirodnoj površini tla, a označava povećanje od 73 % u odnosu na koeficijent na prirodnoj površini tla. Kada seizmički intenzitet postigne određenu vrijednost, područje plastičnosti postupno se pojavljivalo na nasipu, a postoji i kontinuirano proširenje područja plastičnosti koje je povezano s povećanjem vršnog ubrzanja ulaznog seizmičkog vala. Rezultati istraživanja mogu dati uvide i imati značajne implikacije za daljnje istraživanje hladnih područja. To investigate more fully seismic behaviour of the Qinghai-Tibet railway embankment, a comprehensive discussion and a781nalysis is conducted in this paper by applying a numerical technique. Specifically, the one dimensional equivalent linear ground response analysis was conducted in permafrost regions. On this basis, the seismic response of a typical railway embankment was further studied by applying the nonlinear dynamic finite element analysis method. As a result, nonlinear behaviour of permafrost sites was determined, and the dynamic acceleration, velocity and displacement of the embankment was discussed and the quantitative assessment was approximately estimated. The results indicate that the dynamic response of the embankment has distinct nonlinear characteristics. The peak ground acceleration coefficient at the embankment shoulder is larger than the natural ground surface, marking a 73% increase compared to the coefficient on the natural ground surface. When the seismic intensity reaches a certain value, a plastic zone gradually appears in the embankment, and a continuous extension of the plastic zone can be noted with an increase in peak acceleration of the input seismic wave. The findings of this research may provide an additional insight and have significant implications for further research of cold regions.