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11.
Lagoon berms in western Alaska are difficult to design and build due to limited resources, high cost of construction and materials, and warm permafrost conditions. This paper explores methods to treat locally available frozen materials and use them for berm construction. The goal is to find an optimized mix ratio for cement and additives that can be effective in increasing the strength and decreasing the thaw settlement of an ice-rich frozen silty soil. Soil of similar type and ice content to the permafrost found at a project site in Eek, Alaska is prepared in a cold room. The frozen soil is pulverized and cement, additives and fibers are added to the samples for enhancing shear strength and controlling thaw settlement. Thaw settlement and direct shear testsare performed to assess strength and settlement characteristics. This paper presents a sample preparation method, data from thaw settlement and direct shear tests, and analyses of the test results and preliminary conclusions. 相似文献
12.
Lateral spread of frozen ground crust over liquefied soil has caused extensive bridge foundation damage in the past winter earthquakes. A shake table experiment was conducted to investigate the performance of a model pile in this scenario and revealed unique pile failure mechanisms. The modelling results provided valuable data for validating numerical models. This paper presents analyses and results of this experiment using two numerical modeling approaches: solid-fluid coupled finite element (FE) modeling and the beam-on-nonlinear-Winkler-foundation (BNWF) method. A FE model was constructed based on the experiment configuration and subjected to earthquake loading. Soil and pile response results were presented and compared with experimental results to validate this model. The BNWF method was used to predict the pile response and failure mechanism. A p-y curve was presented for modelling the frozen ground crust with the free-field displacement from the experiment as loading. Pile responses were presented and compared with those of the experiment and FE model. It was concluded that the coupled FE model was effective in predicting formation of three plastic hinges at ground surface, ground crust-liquefiable soil interface and within the medium dense sand layer, while the BNWF method was only able to predict the latter two. 相似文献
13.
Stephanie E. Chang Timothy L. McDaniels Joey Mikawoz Krista Peterson 《Natural Hazards》2007,41(2):337-358
This paper addresses the problem of interdependent failures of critical infrastructures in disasters. Disruptions to critical
infrastructure systems such as electric power or transportation frequently cause major social and economic loss in disasters,
both directly and through failures in one system leading to or compounding disruptions in another. Strategic approaches regarding
infrastructure failures are needed to guide community mitigation and preparedness efforts. This paper defines and provides
a conceptual framework for investigating infrastructure failure interdependencies (IFIs) from the standpoint of societal impacts.
In order to identify empirical patterns, a unique database has been developed of IFIs observed in major electric power outage
events. This paper presents analysis of this data for a major Canadian disaster, the 1998 Ice Storm that affected the northeastern
region of the country. The analysis identifies IFIs due to power outage caused by the storm that are of greatest societal
concern. These represent potential foci for effective, targeted pre-disaster mitigation and preparedness efforts. The framework
and approach are broadly applicable across a range of natural and human-induced hazards. 相似文献