دانلود رایگان مقاله انگلیسی رفتار لرزه ای موج شکن ها در زمین های پیچیده با استفاده از تست های عددی - اشپرینگر 2018

Abstract:

A large number of breakwaters have been constructed along coasts to protect humans and infrastructures from tsunamis. There is a risk that foundation soils of these structures may liquefy, or partially liquefy during the earthquake preceding a tsunami, which would greatly reduce the structures’ capacity to resist the tsunami. It is necessary to consider not only the soil’s liquefaction behavior due to earthquake motions but also its post-liquefaction behavior because this behavior will affect the breakwater’s capacity to resist an incoming tsunami. In this study, numerical tests based on a sophisticated constitutive model and a soil-water coupled fi nite element method are used to predict the mechanical behavior of breakwaters and the surrounding soils. Two real breakwaters subjected to two different seismic excitations are examined through numerical simulation. The simulation results show that, earthquakes affect not only the immediate behavior of breakwaters and the surrounding soils but also their long-term settlements due to post-earthquake consolidation. A soil profi le with thick clayey layers beneath liquefi ed soil is more vulnerable to tsunami than a soil profi le with only sandy layers. Therefore, quantitatively evaluating the seismic behavior of breakwaters and surrounding soils is important for the design of breakwater structures to resist tsunamis.

5 Conclusions

Numerical tests were carried out to study the seismic behavior of seabed ground and the anti-tsunami performance of two existing breakwaters constructed forty years ago. It has been clearly illustrated that, in a normal numerical analysis of a practical geotechnical problem, the parameters of the soils involved in a prescribed constitutive model are adjusted to fi t the observed behavior of a boundary value problem (BVP). In a numerical test, however, all of the soil parameters are determined based on element tests or engineering judgments without being infl uenced or modifi ed by the observed behavior of a BVP. The fi nal goal of a numerical test is not only to be able to simulate an actual event but also to predict an event that has not yet occurred when there is only part of the test data or the available information about the soils and some of the parameters are from element tests. The numerical tests were based on a sophisticated constitutive model that could describe the mechanical behavior of different soft soils at the element level in a unifi ed way. Moreover, the corresponding soil-water coupling fi nite element analysis allowed the static and dynamic behavior of the boundary value problem to be treated in a unifi ed way as well. The validity of this numerical method has been proved multiple times in the literature.