铅芯橡胶支座等效线性分析模型参数的研究

针对目前铅芯橡胶支座等效线性分析模型动力参数选取不够合理的现状 ,笔者通过对铅芯橡胶支座水平动态试验分析 ,系统研究了铅芯橡胶支座等效线性分析模型参数与其几何结构及外加动力荷载特性的关系。研究结果表明 :铅芯橡胶支座等效线性分析模型参数 (水平耗能、等效刚度及等效阻尼比 )主要由其本身的几何构造及组成材料决定 ,且在往复加、卸载循环过程中具有较好的稳定性。笔者对试验数据进行数学统计分析 ,归纳出一些经验公式 ,为其等效线性化动力分析模型参数的合理选取提供了计算方法 ,从而提高其动力分析结果的安全性。     

近断层地震动考虑能量损伤效应的非弹性强度需求

由于靠近断层处地震地面运动中速度脉冲作用的存在,导致传统的基于瞬时加速度反应谱的抗震设计,不能有效考虑由此带来的巨大能量耗散和位移需求。笔者采用代表性的脉冲型实际近场地震记录和人工模拟三角函数地震动时程,在分析累积输入地震动耗能和结构位移间关系基础上,提出了等效速度比的表达式;给出了近场地震动的等效变形需求表达式;提出了等价延性系数的概念,来考虑由于地震动能量耗散对结构的强度需求;经非线性时程分析方法对其稳定性进行了验证比较,有利于增强结构的安全性。     

大直径桩端阻力面积修正系数研究

桩端阻力和桩端直径呈非线性关系,随着桩端直径的增加而逐渐减小。本文根据线弹性理论和非线性弹性理论分别求得大直径灌注桩桩端阻力的面积修正系数的上限解和下限解,得到了桩端土承载力标准值与桩端直径的非线性关系和桩端土承载力面积修正系数与桩端直径的非线性关系。与现行建筑桩基技术规范相比,当桩径 0．80～3．00 m时,规范给定的面积修正系数稍大于理论上限值,其它桩径范围的桩端面积修正系数均在理论值的上、下限范围。当桩径0．80～2．00 m时,按规范给定的面积修正系数修正后的承载力标准值稍大于理论上限值, 其它桩径范围按规范修正后的桩端土承载力标准值均在理论值的上、下限范围。     

等效数值模型用于污水综合排放级别划分研究

依据国家污水综合排放标准 ( GB8978-1 996) ,建立了多污染成分的污水排放级别的等效数值模型 ,应用表明 :该模型符合实际 ,对污水排放的环境管理具有重要的意义     

单一震源地震发生的等效物理模型

建立了模拟单一潜在震源区地震孕育和发生的等效物理模型，给出了通过调整各次地震之间断层位移速率来拟合已有地震序列的方法。通过考虑模型参数的不确定性，提出了在未来一定年限内潜在震源区发生震级在不同震级段的概率预报方法。通过两种等效物理模型的对比，本文认为就工程地震危险性评定而言，可用简单的滑块－弹簧模型代替滑块－弹粘塑性模型     

高速铁路声屏障对居民环境影响的试验研究

以三种结构的高速铁路声屏障为研究对象,测量了高速列车通过有声、无声屏障两种状态下8个测点的声压值,并计算各测点等效连续A计权声压和声屏障的隔声量,结合GB3096-2008中规定的环境噪声限值进行声屏障结构对高速铁路周边居民的声环境影响评价。试验分析结果表明:声屏障不同程度改善了居民的声环境;由于试验所用的三种结构的声屏障隔声量离一般设计要求(20~25dB(A))相差太远,使得高速铁路周边环境噪声高于国家标准规定限值;声屏障结构改进应着力提高中低频噪声的隔声量。     

Unignited High-Pressure Methane Jet Impinging a Pipe Rack: Practical Tools for Risk Assessment

Although the diffusion of its storage and transport under liquefied conditions, nowadays it is common to have methane in gaseous form in several industrial applications. This leads to safety implications to be considered: hazards are linked to both the high-pressure at which the gas is kept and to its flammability. Scenarios where flammable jets impact an obstacle are of paramount importance because of their possible occurrence. Following a numerical approach, literature shows up that their assessment can be reliably performed by means of only Computational Fluid Dynamics tools. However, despite the improvements of computing power, Computational Fluid Dynamics costs still limit its use in daily risk analysts’ activities. Therefore, considering an accidental jet-obstacle scenario of industrial interest, the present work investigates how a pipe rack can influence the development of a high-pressure methane jet. Based on a Computational Fluid Dynamics analysis, main achievements of this work are a simple criterion able to identify the situations where the pipe rack does not influence the high-pressure methane jet behavior, therefore allowing to identify the scenarios where simpler models can be used (i.e., analytical correlations known for the free jet situation), and, if present, a simple analytical relationship that roughly predicts the influence of the pipe rack without the need of performing complex Computational Fluid Dynamics simulations.     

汽车制造业验收监测中排气筒等效计算的探讨

通过对某一汽车制造企业等效排气筒组的实际监测与相关参数计算的分析,讨论并提出了对此类排气筒组等效排气筒高度的计算方法.     

Equivalent roaded area as a measure of cumulative effect of logging

A watershed disturbance index developed by the USDA Forest Service called equivalent roaded area (ERA) was used to assess the cumulative effect from forest management in California's Sierra Nevada and Klamath mountain ranges. The basins' ERA index increased as logging and road-building occurred and then decreased over time as management ceased and vegetation recovered. A refinement of the standard index emphasized disturbances in sensitive, near-channel areas, and evaluated recovery periods of 20, 30, and 50 years. Shorter recovery periods yielded better correlations between recovering forest systems and aquatic response than the longer recovery period, as represented by ERA and diversity or dominance, respectively. The refined ERA index correlated more closely with macroinvertebrate dominance and diversity information that was available for part of the study period. A minimum ERA threshold of 5% was detected, below which no effect to the macroinvertebrate community was observed. Above this threshold, elevated ERA values were associated with a decline in macroinvertebrate diversity and an increase in dominance of the top five taxa. Use of an ERA technique that emphasizes near-channel areas and biological thresholds would contribute to the Forest Service's implementation of ecosystem management.     

人身伤亡赔偿计算方法及理论依据新探

全面、准确、合理的估算并给出因人身伤亡产生的赔偿金额,目前似乎是一个世界性的难题。这主要由于人们受生命伦理观念的束缚而未曾深入探讨个体生命在社会生活中的经济学意义。笔者通过分析和总结现存赔偿方法的缺陷和理论认识的不足,参照一般性实物的损坏赔偿原则,引申提出了人身伤亡赔偿的新理论。该理论认为:对人的赔偿也应当遵循“损失有多大赔偿就应当有多少”的世界通行原则。因此,对由于受伤或死亡带来的工资收入、生命健康和精神创伤三大损失,应当逐项予以合理的估算和足额的赔偿。根据该观点,笔者设计整合了一套相对完整的赔偿计算公式,从而为解决人身伤亡的赔偿难题提供了一种新的选择。