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为了解决桥下堆积物燃烧对混凝土墩身的影响问题,以某桥梁工程9~#桥墩、10~#桥墩以及两墩之间的三七遮阳网作为研究对象,采用FDS和ANSYS数值仿真分析的方法,并与火灾后桥墩的现场调查结果进行对比。结果表明:火灾影响最严重的部位可以通过墩身表面温度大于800℃的面积(S800℃)、墩身内部温度大于100℃的壁厚(b100℃)这两个参数来判定;混凝土墩的表面最大剥落高度可以通过墩身表面温度大于300℃的墩高、横截面内部温度大于100℃的墩高(H100℃)来判定,研究提出的4个参数对其他类似工程有一定的借鉴意义。 相似文献
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An interesting result with the products of crystallization being dominated by the cooling rate has been raised in the crystallization of ethylenediamine (EDA)-directed cobalt phosphates and 1,2-diaminopropane (PDA) -directed zinc phosphates. To explore the reason and mechanism behind this phenomenon,these two systems were crystallized under different temperatures from 1 to 6 d followed by fast cooling (in 10 min) or slow cooling (in 3 h) route, respectively. The results showed that, within a certain range ofcrystallization time, slow cooling rate would result in a framework transformation. Further investigation indicates that this transformation is lower-temperature-preferable in EDA-CoPO4 system, and the slow cooling process give the system a period of time to carry out the transformation under lower temperature. However, in PDA-ZnPO4 system, a higher-temperature-preferable transformation has been found, and further study on SAPO-CHA presents a similar result, which is in consistent with general transformation conditions of most crystals, which protrudes the uniqueness of EDA-directed crystallization of cobalt phosphates systems. 相似文献
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采用径向剖分的有限元法对井地三维电阻率法进行数值模拟,以适应不同观测装置对数值模拟的要求。以井口为中心,将区域在环钻孔方向以45°夹角均匀剖分为八等分,再在直径方向上等距离剖分。径向剖分形成的单元呈环形分布,更符合井中电场的分布规律。与这种剖分相对应,设计了以井口为中心布置4条放射状测线("米"字形)的井地观测装置,解决了井旁地质体位置未知的情况下难以确定观测方向的问题。通过对典型的地质模型进行有限元正演模拟计算,结果表明径向剖分数值模拟方法是可行的、准确的;以这种井地观测方式探测位置未知的地质体是行之有效的。 相似文献
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