土与结构相互作用体系振动台模型试验数值模拟研究(英文)

运用土与结构动力相互作用 (SSI)有限元三维分析软件 SASSI2 0 0 0对一个土与结构动力相互作用体系振动台模型试验进行了模拟计算。对振动台模型试验作了简单的介绍 ,并详细叙述了试验的建模方法。对于试验中的刚性地基和柔性地基条件 ,El- centro波、Taft波和 5 0年超越概率为 10 %的南京人工波等三种地震波输入 ,三个加速度峰值水平 0 .1g、0 .2 g、0 .3g及两个水平向地震波输入的各种组合工况均进行了计算。在数值计算中 ,假设地基土为覆盖于基岩上的半无限粘弹性水平成层土 ,采用等效线性模型考虑土的动力非线性的影响 ;上部结构用三维杆系有限元单元模拟 ,楼板用四结点壳单元模拟 ,每个结点有三个平动自由度和三个转动自由度 ,模型试验中所施加的人工质量均匀分布于壳单元上 ;基础视为平板基础 ,用八结点块体单元模拟 ,每个结点有三个平动自由度。将试验结果与计算结果进行对比较 ,结果表明 :计算所建立的模型较好地模拟了相互作用体系在地震荷载下的反应性状 ,计算结果与试验结果吻合较好 ,SSI效应对结构地震反应有很大影响     

黄土地基湿陷时桩的负摩阻力最大值出现深度研究

负摩阻力及中性点的定义表明,负摩阻力沿桩身(从桩顶两侧到中性点位置)的变化并不均匀,其间应存在一个最大值,最近的黄土地基浸水湿陷试验证明了这一点。本文利用该试验的资料,从理论上对桩的负摩阻力最大值出现深度进行分析研究,结果表明负摩阻力随深度的变化受到某一深度(如负摩阻力最大值处)以上土体有效重量和该深度桩周土体的有效沉降量这两个主要因素的制约,并由此推导出不同沉降性能土体湿陷时桩的负摩阻力最大值出现的深度。通过与实测资料的对比可见,本文提出的确定桩的负摩阻力最大值出现深度的理论是可信的,由此得到的计算黄土地基湿陷时桩身总的负摩阻力的方法更具合理性。     

Evaluation of the california environmental quality act

The California Environmental Quality Act (CEQA) has evolved from a mini-NEPA, first enacted in 1970, into a procedural act that affects the approval process of all large developments in California. In 1990, California local governments produced over 1600 environmental impact reports and 30,000 initial studies under CEQA. Because of its widespread use, CEQA has periodically drawn the attention of the state legislature, most recently in 1993, when over 60 CEQA reform bills were introduced. This paper describes the CEQA process and evaluates its success at meeting its explicit and implicit goals. The research includes a statewide survey of CEQA practice, sent to the planning departments of all 513 local governments in California in 1991. Survey respondents agreed that CEQA helps in evaluating environmental impacts, reducing impacts, informing the public, and coordinating public agency review. It is effective in reducing the environmental impacts of individual projects, but is not as effective in improving environmental quality on an areawide scale. This research concludes that CEQA has led to positive outcomes and is not as deeply flawed as many of its critics claim. Still, CEQA as currently designed may not be the optimal vehicle for ensuring environmental quality.     

生活事件分析法在煤矿企业中的应用

我国煤矿一再的发生事故,绝大部分原因是人为失误.根据人为失误的发生机理,本文提出了生活事件分析方法,并研制了其配套应用程序,对某煤矿企业的人因事故危险性进行了实际评价.该方法可方便地应用于煤矿企业人为事故的预防工作中.     

可视化通风机性能测试程序设计

介绍了用通风机性能曲线测定可视化计算机程序的设计。该程序基于Windows环境，采用C Builder5．0开发，可以实现数据的自动保存、处理，及性能曲线、结果报表输出，同时具有可视化的人机界面。应用该程序可以使通风机性能曲线测定试验更加简便易行，还可以使试验结果更加精确。     

焦化厂火灾应急预案的建立

从焦化生产的工艺以及产品的特性入手，分析了焦化厂潜在的火灾事故隐患以及发生事故的可能性，强调了焦化厂作为一个化工企业建立应急预案的必要性。阐述了建立应急预案的注意事项和内容。     

水入渗条件下边坡破坏离心模型试验研究

水的人渗能对土体强度产生较大的影响,它是造成边坡破坏的一个主要因素.不同含水量土质边坡的离心模型试验表明:边坡的破坏类型与其含水量大小有关,且主要存在两种破坏类型:一种是含水量较小时形成的拉裂缝破坏,另一种是含水量较大时形成的整体滑塌破坏;同时,含水量与边坡的最大稳定高度呈非线性关系.进一步的损伤力学分析表明,随着土体含水量的增加,损伤变量增大,并存在一个突变点;通过同离心模型试验结果比较,发现该突变点对应的含水量可作为两种破坏类型的判据.     

稠油污水处理系统改造与絮凝剂筛选试验研究

河南油田井楼稠油联合站含油污水中的污油和悬浮物含量较高,超过150mg/L。为此,对该处理系统进行了改造,并对絮凝剂的筛选进行了试验。结果表明:无机絮凝剂与有机絮凝剂联合作用,可对污水中所含有的污油和有机物杂质的悬浮物产生很好的絮凝沉降效果。加药浓度、加药顺序及沉降时间均对絮凝沉降效果有一定的影响。改造后的污水处理系统实现了污水达标回注,降低了无效回注费用。同时还回收了污油,降低了药剂成本,产生了十分明显的经济效益,每年节约成本约500万元。     

ENHANCING FECAL COLIFORM TOTAL MAXIMUM DAILY LOAD MODELS THROUGH BACTERIAL SOURCE TRACKING1

ABSTRACT: Surface water impairment by fecal coliform bacteria is a water quality issue of national scope and importance. In Virginia, more than 400 stream and river segments are on the Commonwealth's 2002 303(d) list because of fecal coliform impairment. Total maximum daily loads (TMDLs) will be developed for most of these listed streams and rivers. Information regarding the major fecal coliform sources that impair surface water quality would enhance the development of effective watershed models and improve TMDLs. Bacterial source tracking (BST) is a recently developed technology for identifying the sources of fecal coliform bacteria and it may be helpful in generating improved TMDLs. Bacterial source tracking was performed, watershed models were developed, and TMDLs were prepared for three streams (Accotink Creek, Christians Creek, and Blacks Run) on Virginia's 303(d) list of impaired waters. Quality assurance of the BST work suggests that these data adequately describe the bacteria sources that are impairing these streams. Initial comparison of simulated bacterial sources with the observed BST data indicated that the fecal coliform sources were represented inaccurately in the initial model simulation. Revised model simulations (based on BST data) appeared to provide a better representation of the sources of fecal coliform bacteria in these three streams. The coupled approach of incorporating BST data into the fecal coliform transport model appears to reduce model uncertainty and should result in an improved TMDL.     

我国安全学科学历教育的困境与对策

我国安全形势严峻的重要原因是安全科技人才缺乏。安全学科学历教育作为我国安全科技高级人才培养的主要渠道之一,为国家造就和输送了大批安全科技人才。但是,由于安全学科学历教育体制没有很好适应市场经济的发展,遇到了不少难以解决的问题。依据对高校和煤炭企业调查所获得的资料,统计发现:目前我国安全学科学历教育所面临的主要问题是专业设置的局限性、培养目标的雷同性和课程设置的低通用性;社会对安全人才需求与目前高校安全专业招生和毕业生就业之间存在的突出矛盾。在详细调研和分析的基础上,提出了相应的安全人才后备队伍建设应采取的对策,即加大政府调控力度、实施“人才兴安”战略,深化教育教学改革、培养高素质安全人才。