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101.
压实度对路基回弹模量的影响分析 总被引:1,自引:0,他引:1
路基回弹模量是反映路基承载能力的主要力学参数,它的确定直接影响到路面的设计厚度,因此有关路基回弹模量的研究具有十分重要的意义。选定三种不同类型的路基填料,分析在不同压实度条件下路基回弹模量的变化规律,并结合PFWD(便携式落锤弯沉仪)检测方法,将设计参数回弹模量与施工控制指标压实度联系起来,得出三种路基填料的回弹模量与压实度的转换关系,可为路面设计与施工提供合理的依据。 相似文献
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地铁网络突发重大事故后,通常会启动公交接驳疏散滞留乘客。提出衡量网络性能的网络效率可达性指标,考虑地铁站点发生故障后公交接驳对乘客的紧急疏散作用。基于网络效率可达性指标构建韧性评估模型,提出多故障下以韧性最大化为目标的修复策略,并以上海市地铁网络为例进行实例研究。研究结果表明,单个站点发生故障后启动公交接驳可使网络性能损失降低5.1%;占网络站点总数2.14%的多个站点发生故障后启动公交接驳可使网络性能损失降低13.48%;多故障下相比基于站点度、介数、脆弱性等评估得到的修复序列,基于韧性评估得到的最优修复序列可使网络性能累积损失降低2.86%。此外,研究发现在公交接驳场景下,当地铁网络中多个站点发生故障后,优先修复客流量大、站点周边线路稀疏、失效后造成影响大且修复时间短的站点,有助于降低网络性能的累积损失。 相似文献
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应用便携式落锤弯沉仪测定路基回弹模量 总被引:30,自引:0,他引:30
应用便携式落锤弯沉仪(PFWD),研究了动弹性模量与压实度和含水量的关系,得出动弹性模量与静弹性模量、压实度和含水量相关系数大于0.85,动弹性模量最大值在最佳含水量附近,这与实际情况相符.结果表明,PFWD可用于路基回弹模量的快速检测和评价. 相似文献
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This paper analyzes the interdependency across two critical infrastructures of transportation and motor fueling supply chains, and investigates how vulnerability to climatic extremes in a fueling infrastructure hampers the resilience of a transportation system. The proposed model features both a bi-stage mathematical program and an extension to an ‘α-reliable mean-excess’ regret model. The former aspect allows decision makers to optimize the pre-disaster asset prepositioning against the maximum post-disaster system resilience. The latter aspect of the proposed model devalues the impact of ‘low-probability, high-cost’ sub-scenarios upon model results. The model reveals the reliance of post-disaster urban mobility on the interdependent critical infrastructure of motor fueling supply chains. The results also suggest how investment in the fueling infrastructure’s vulnerable elements protects urban mobility while the transportation network is stressed or under attack. 相似文献
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Livelihood diversification can increase the number of activities generating income and is often adopted as a means to reduce vulnerability to risk and provide a pathway out of poverty. Previous empirical studies, however, have found that this diversification carries no guarantee of success. This study examines the impacts of investments in conservation-based enterprises and micro-credit interventions implemented in coastal Tanzania. Project beneficiaries (n = 178) and non-beneficiaries (n = 117) from seventeen communities surrounding Saadani National Park and the Menai Bay Conservation area were surveyed in 2013, to gather quantitative and qualitative data on a suite of parameters including the number of livelihood activities, total annual income, and engagement in extractive activities. We found that the beneficiaries reported an average of 2.15 livelihoods, which was significantly higher than the 1.44 average reported by the non-beneficiaries. The beneficiaries also had significantly higher mean annual incomes than the non-beneficiaries as the former reported an annual mean income of US $2,076 while the latter reported US $646. The research found a complex relationship between occupational diversity and people's interactions with the environment and it is clear that livelihood diversification is not a blanket solution to reducing pressure on coastal resources. Another important finding from the research is that there are distinct differences between types of livelihood interventions and it is crucial to be clear about the goal of a livelihoods intervention. If the goal is diversifying livelihoods and strengthening resilience, then livelihoods that provide a small and steady income for many entrepreneurs may be enough. However, if the goal is to bring people out of a poverty trap, then it makes more sense to invest in livelihoods that bring in a higher income, even if that means reaching fewer beneficiaries. 相似文献
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Amber Himes-Cornell Carlos Ormond Kristin Hoelting Natalie C. Ban J. Zachary Koehn Edward H. Allison 《Coastal management》2013,41(5):335-358
AbstractDisaster research often focuses on how and why communities are affected by a discrete extreme event. We used the community capitals framework to understand how community characteristics influence their preparedness, response to, and recovery from successive or multiple disasters using the 1964 Good Friday Earthquake and the 1989 Exxon Valdez Oil Spill as case studies. This study assesses community response to these disasters by reviewing published literature on impacts to create profiles for six communities and by identifying community capitals before and during these disasters, and throughout the long-term recovery. While the presence of rich natural capitals commonly contributed resources to pre-disaster planning and long-term recovery, restriction of resource access immediately following the disasters was detrimental to many communities. Communities with strong political, social, and financial capitals tended to fare better immediately following disasters, enabling longer-term processes of transformation or recovery. However, in some communities the oil spill undermined these capitals more than the earthquake and resulting tsunami. In understanding how use and reliance on community capitals can lead to varied recovery success from different kinds of disasters, these findings can help coastal managers and planners prepare for future disasters. 相似文献