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991.
992.
Based on non-Darcian flow law described by exponent and threshold gradient within a double-layered soil, the classic theory
of one-dimensional consolidation of double-layered soil was modified to consider the change of vertical total stress with
depth and time together. Because of the complexity of governing equations, the numerical solutions were obtained in detail
by finite difference method. Then, the numerical solutions were compared with the analytical solutions in condition that non-Darcian
flow law was degenerated to Dary’s law, and the comparison results show that numerical solutions are reliable. Finally, consolidation
behavior of double-layered soil with different parameters was analyzed, and the results show that the consolidation rate of
double-layered soil decreases with increasing the value of exponent and threshold of non-Darcian flow, and the exponent and
threshold gradient of the first soil layer greatly influence the consolidation rate of double-layered soil. The larger the
ratio of the equivalent water head of external load to the total thickness of double-layered soil, the larger the rate of
the consolidation, and the similitude relationship in classical consolidation theory of double-layered soil is not satisfied.
The other consolidation behavior of double-layered soil with non-Darcian flow is the same as that with Darcy’s law. 相似文献
993.
Influence of subsequent curing on water sorptivity and pore structure of steam-cured concrete 总被引:1,自引:0,他引:1
Steam-cured condition is found to cause larger porosity and worse properties of concrete compared with normal curing condition.
For the sake of seeking effective measurements to eliminate this bad effect of steam-cured condition on concrete, the water
sorptivity and pore structure of steam-cured concretes exposed to different subsequent curing conditions were investigated
after steam-curing treatment. The capillary absorption coefficient and porosity of the corresponding concretes were analyzed,
and their mechanisms were also discussed. The results indicate that water sorptivity and pore structure of steam-cured concrete
are greatly influenced by the curing condition used in subsequent ages. Exposure steam-cured concrete to air condition has
an obviously bad effect on its properties and microstructures. Adopting subsequent curing of immersing steam-cured concrete
into about 20 °C water after steam curing period can significantly decrease its capillary absorption coefficient and porosity.
Steam-cured concrete with 7 d water curing has minimum capillary absorption coefficient and total porosity. Its water sorptivity
is decreased by 23% compared with standard curing concrete and the porosity is 9.6% lower. Moreover, the corresponding gradient
of water sorptivity and porosity of steam-cured concrete both decrease, thus microstructure of concrete becomes more homogeneous. 相似文献
994.
A series of Ag, Cu and Co-doped manganese oxide octahedral molecular sieves (OMS-2) were synthesized and evaluated to remove
nitrogen oxides (NO
x
) from cigarette mainstream smoke. The three kinds of catalysts were added to cigarettes for studying the capabilities of
reducing NO
x
from cigarette mainstream smoke. The catalysis and reduction of NO in laboratory were studied. A mechanism for NO
x
catalytic reduction from burning cigarettes with the catalysts adding to cigarettes was described. The catalysts show excellent
catalytic activity for NO
x
removal, especially the Ag-doped OMS-2 catalyst. 0.5% (mass fraction) Ag-doped OMS-2 catalyst has the best ability to remove
NO
x
from cigarette mainstream smoke. The use of Ag-doped OMS-2 as catalyst for removing carcinogenic compounds from cigarette
smoke will be an effective strategy to protect the environment and public health. 相似文献
995.
研究通过调查问卷的形式,收集学生身体健康与宿舍环境的信息,并利用SPSS对数据进行整理分析,旨在得出高校宿舍潮湿与学生呼吸道疾病症状之间的关系.研究结果表明57.9%的同学报告宿舍出现潮湿表征,43%的同学在最近12个月内出现呼吸道疾病症状,室内潮湿与学生呼吸道疾病症状之间存在显著相关性(P<0.05),室内的潮湿表征是呼吸道疾病症状爆发的危险因素(OR 2.362 95%CI),同时,研究发现学生呼吸道疾病症状的爆发以及室内潮湿表征与宿舍朝向有关. 相似文献
996.
油气藏开发过程的实质就是一个流体置换的过程,这就为非一致性采集资料地震监测提供了可能。本文基于gassmann方程,详细地分析了流体替代时储层物性参数(地震波速度,密度,泊松比等)的变化规律,建立了相应的孔隙度变化地震地质模型。最终对该模型所提取的振幅类属性进行优选技术处理,找到了适合本工区的两种敏感振幅属性,为准确预测目的储层段剩余油的分布奠定了基础。 相似文献
997.
998.
某RCC重力坝坝基巨型溶蚀大厅规模大,坝基以下岩体厚度小,发育深度大,坝基开挖爆破导致洞顶以上岩体松动,存在坝基塌陷的安全隐患.在充分研究区域地形地质条件的基础上,采用三维非线性有限元法研究了不同施工方案下坝基巨型溶蚀大厅的应力场、位移场及破坏区分布,并在此基础上提出溶蚀大厅的加固处理方案及喷锚支护参数. 相似文献
999.
Doddi YUDIANTO 《水科学与水工程》2012,5(3):278-290
Phosphorus is one of the most important nutrients required to support various kinds of biodegradation processes. As this particular nutrient is not included in the activated sludge model no. 1 (ASM1), this study extended this model in order to determine the fate of phosphorus during the biodegradation processes. When some of the kinetics parameters are modified using observed data from the restoration project of the Xuxi River in Wuxi City, China, from August 25 to 31 in 2009, the extended model shows excellent results. In order to obtain optimum values of coefficients of nitrogen and phosphorus, the mass fraction method was used to ensure that the final results were reasonable and practically relevant. The temporal distribution of the data calculated with the extended ASM1 approximates that of the observed data. 相似文献
1000.