模糊层次评价法在隧道地质灾害评估中的应用

运用模糊层次评价法对椿树垭隧道施工中可能遇到的地质灾害风险进行了评估。采用德尔菲法建立了椿树垭隧道地质灾害风险评价指标体系;运用层次分析法计算各风险因素的相对权重;以问卷调查的形式对各风险因素进行单因素评价并建立模糊关系矩阵;采用模糊综合评价法计算出椿树垭隧道地质灾害的风险等级及风险值。评估结果:在椿树垭隧道施工中最可能发生的地质灾害风险是岩溶和岩爆,其次为塌方和涌水,而发生大变形和瓦斯的可能性则非常小。椿树垭隧道整体综合评价风险等级为三级,即中等风险。应用表明:该方法是可行的,可以为隧道施工制定或完善施工方案和确定综合超前地质预报方法提供依据。     

大型公共建筑风险评估框架研究

大型公共建筑是开放复杂系统,其风险由可靠性风险、安全性风险和可持续发展性风险构成.大型公共建筑的风险评估、需要从系统的角度,针对3类风险的不同特性,采用定性与定量结合的方法,进行系统的风险评估.针对可靠性风险侧重系统的可靠程度评估,安全性风险侧重风险源和系统脆弱性评估,可持续发展性风险侧重关联风险事件评估.大型公共建筑...     

PPP项目风险分担研究评述

通过整理和分析大量文献,界定风险分担的概念并对该领城研究进行详细的归类阐释,从中提炼出PPP项目风险分担的三种基本研究路径:理论推演、理论应用和实践总结,得出PPP项目风险分担研究具有三个薄弱环节,即风险分担的过程评价、风险分担比例的确定以及风险分担与其他方面的关联关系,从而指出该领城未来的研究方向.     

大型集群式工程项目的WBS-RBS风险识别方法及其应用

简述了大型集群式工程项目的风险与风险群概念,对WBS-RBS的组合矩阵风险分析模型做了介绍。以广州亚运海心沙工程项目为例,描述了使用该模型构建起大型集群工程项目风险分析矩阵的方法。并结合实际使用效果,对WBS-RBS风险分析模式做出评价。     

基于蒙特卡罗法的施工成本扰动风险研究

针对项目施工过程中成本风险对企业影响最为深远这一问题,利用蒙特卡罗方法对工程项目施工阶段成本的风险特性进行有效分析。而依据成本分析的蒙特卡罗方法建立的工程项目成本风险指标体系的模型,能够对成本进行估算能够达到预期效果,不仅有助于提高投资决策的可靠性,而且有助于了解项目所承受的各种风险,便于提出各种措施提高应对项目成本风险的能力。     

包兰铁路青天寺隧道运营通风及防灾救援设计

青天寺隧道长度超过20 km,隧道的运营通风、防灾及救援(含紧急救援站)等,考虑的因素非常多,本文通过包兰铁路青天寺隧道运营通风及防灾救援设计的工程实例,介绍了特长隧道运营通风及防灾救援设计主要应考虑的问题和工程措施。通过数值模型计算,青天寺隧道运营通风得出可采用自然通风方式的结论;论述了定点救援和隧道内随机停车救援的原理和措施;对隧道内需要设置的通风机功率进行了详细的计算,对不同火灾工况的防灾通风形式、人员的疏散、风机的配置等进行了系统的论述。为以后类似工程设计提供参考。     

Health risk assessment on dietary exposure to polycyclic aromatic hydrocarbons (PAHs) in Taiyuan, China

Twenty-five kinds of seven categories of foods were sampled in December 2008 and the concentrations of 16 polycyclic aromatic hydrocarbons (PAHs) were determined. The highest level of total PAHs was detected in pork (195.30 ng/g) whereas the lowest concentration was found in milk (8.73 ng/g). The median values of B[a]P equivalent (B[a]P_eq) daily exposure doses for children, adolescents, adults and seniors of male were estimated to be 392.42, 511.01, 571.56 and 532.56 ng/d, respectively, whereas those for the above population groups of female were found to be 355.16, 440.51, 487.64 and 444.85 ng/d, respectively. The incremental lifetime cancer risk (ILCR) values at the 22.1th, 26.1th, 12.7th, 24.9th, 22.7th, 27.0th, 12.9th, and 25.5th percentiles for male children, male adolescents, male adults, male seniors, female children, female adolescents, female adults and female seniors, respectively, were larger than 10^− 6, indicating high potential carcinogenic risk, and were larger than 10^− 4 at the 74.5th, 78.7th, 60.6th, 77.4th, 75.3th, 79.5th, 60.8th and 77.9th percentiles for the above groups, respectively, which implied significant cancer risk. Sensitivity analysis found that the two variables of oral cancer slope factor of benzo(a) pyrene (SF) and the daily dietary PAH exposure level (ED) had the greater impact than that of body weight (BW) on the ILCR.     

Assessing the public health risk of microbial intrusion events in distribution systems: conceptual model, available data, and challenges

Low and negative pressure events in drinking water distribution systems have the potential to result in intrusion of pathogenic microorganisms if an external source of contamination is present (e.g., nearby leaking sewer main) and there is a pathway for contaminant entry (e.g., leaks in drinking water main). While the public health risk associated with such events is not well understood, quantitative microbial risk assessment can be used to estimate such risk. A conceptual model is provided and the state of knowledge, current assumptions, and challenges associated with the conceptual model parameters are presented. This review provides a characterization of the causes, magnitudes, durations and frequencies of low/negative pressure events; pathways for pathogen entry; pathogen occurrence in external sources of contamination; volumes of water that may enter through the different pathways; fate and transport of pathogens from the pathways of entry to customer taps; pathogen exposure to populations consuming the drinking water; and risk associated with pathogen exposure.     

Polycyclic aromatic hydrocarbons (PAHs) in urban surface dust of Guangzhou, China: Status, sources and human health risk assessment

Ninety-six urban surface dust samples collected from Guangzhou, a typical urban center in South China, were analyzed for 16 PAHs (2-6 rings). ∑ PAHs concentrations in the urban surface dust ranged from 0.84 to 12.3 μg/g with a mean of 4.80 μg/g. High molecular weight compounds (4-6 rings) contributed to 62 to 94% of ∑ PAHs mass in the surface dust samples. Four hotspots with highest ∑ PAHs were identified via kriging prediction mapping, representing the highly-urbanized regions: central downtown, highway and industrial area. Two major origins of PAHs inputs to urban surface dust were identified as vehicle emissions (51.9%) and coal combustion (26.8%). The 95% UCL of Incremental Lifetime Cancer Risk (ILCR) due to human exposure to urban surface dust PAHs in central South China was 3.03 × 10⁻⁶ for children and 2.92 × 10⁻⁶ for adults.     

冰冻灾害及其他心理因素对脑出血发病的影响

目的探讨冰冻灾害及其他社会心理因素对脑出血患者发病的影响。方法应用自制一般情况量表、生活事件量表、社会支持量表、特质应对方式问卷、A型行为类型评定量表对60例脑出血患者及60例健康体检者进行病例对照研究。结果冰冻灾害、文化、职业、高血压病史、糖尿病病史、卒中家族史、正性事件刺激量、负性事件刺激量、事件刺激总量、主观支持、对支持的利用度、消极应对、积极应对,脑出血患者与健康体检者比较差异有统计学意义（P〈0.05或P〈0.01）。多元逐步Logistic回归分析发现：冰冻灾害、高血压病史、负性事件刺激量与脑出血呈正相关（P〈0.05或P〈0.01）,主观支持与脑出血呈负相关（P〈0.05）。结论冰冻灾害作为社会环境因素对脑出血患者发病有明显影响。