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891.
In this paper the probability of green water occurrence is investigated by taking into account the threshold of the vertical relative motion exceeding the freeboard. The number of wetting of the unit/vessel is predicted using probabilistic method. This paper compares the significant load, due to shipping of green water with the works of other researchers, and the loads are found to be close with the results presented in this paper. There is no direct relation between the velocities in the waves and the water velocity over the deck. The water velocities around the bow are heavily distributed by the presence of the bow. This scenario makes the flow very complex for schematic modelling. 相似文献
892.
构造形成序列的砂箱实验研究──以黄骅盆地中区新生代构造为例 总被引:3,自引:2,他引:1
按照黄骅盆地中区典型构造剖面设计砂箱实验模型,实验结果表明,通过砂箱实验可以有效重现构造形成的过程和序列,黄骅盆地中区新生代构造形成序列是:歧东构造带、歧中构造带、自东构造带、新港断层带,在同一构造带中断层形成的总体顺序是北倾断层略早于南倾断层。 相似文献
893.
894.
895.
896.
地理信息系统集成平台框架结构研究 总被引:51,自引:3,他引:48
提出了基于客户/服务器结构的地理信息系统集成平台总体结构,探讨了基于元数据的地理信息系统数据集成平台以建立物理上分布而逻辑上集中的分布式地理信息系统数据库,提出了应用符合3NF范式的关系数据库进行模型管理的模式,在此基础上探讨了地理信息系统可视化建模工具。 相似文献
897.
M. Thangarajan 《Environmental Geology》1999,38(3):209-222
Palar River Basin, a crystalline rock region in North Arcot District (Tamil Nadu), India, possesses vast groundwater potential
along and near the river course and its lands are fertile. Serious contamination of both surface water and groundwater has
been reported in this basin as a result of uncontrolled discharge of untreated effluents by the tanning industries for the
last three decades. The health of the rural farming community and people working in the tanning industries has been seriously
affected and they are suffering from occupational diseases such as asthma, chromium ulcers and skin diseases. About an 11000
hectares area of fertile land has lost its fertility. Total dissolved solids (TDS) concentration in groundwater at some pockets
varies from 3000 to 10000 mg/l. As the discharge of effluents is continuing, a prognosis of further pollutant migration is
carried out using a mathematical model. A numerical model of the Upper Palar River Basin was developed using the finite difference
technique coupled with method of characteristics and used to predict TDS migration for the next 20 years. Sensitivity analysis
was carried out to identify the parameters which are influencing the contaminant migration. Sensitivity analysis shows that
advection and not dispersion is the predominant mode of solute migration in Palar Basin. Prognosis using the model confirms
that the polluted area zone as well as the concentration of pollutants in the groundwater will continue to increase in future.
The study also indicated that even if the pollutant sources are reduced to 25% of the present level, the TDS concentration
level in the groundwater, even after 20 years, will not be reduced below 50% of its 1992 level.
Received: 20 June 1998 · Accepted: 26 October 1998 相似文献
898.
土钉墙与压密注浆在复杂地质条件下基坑中的应用 总被引:1,自引:0,他引:1
通过上海长途客运公司恒丰路高速客运站基坑土钉支护工程实例,阐明了土钉支护在复杂地质条件下的适用性及灵活性,并提出了相应处理措施,说明了只有有效地结合其他多种施工方法,才能更好地处理复杂情况。 相似文献
899.
Autoregressive models have been shown to adequately model the time series of significant wave height. However, since this series exhibits a seasonal component and has a non-gaussian nature, it is necessary to transform the series before a model can be fit to the data. Two different transformations that have been used in earlier work are shown not to be appropriate for all types of applications. A third transformation is proposed here, which combines the better features of the two earlier ones and which is appropriate for simulation work. This is demonstrated with an example of a series from Figueira da Foz, a location of the Portuguese Coast. 相似文献
900.
In this paper, a study on the transient response of an elastic structure embedded in a homogeneous, isotropic and linearly elastic half-plane is presented. Transient dynamic and seismic forces are considered in the analysis. The numerical method employed is the coupled Finite-Element–Boundary-Element technique (FE–BE). The finite element method (FEM) is used for discretization of the near field and the boundary element method (BEM) is employed to model the semi-infinite far field. These two methods are coupled through equilibrium and compatibility conditions at the soil–structure interface. Effects of non-zero initial conditions due to the pre-dynamic loads and/or self-weight of the structure are included in the transient boundary element formulation. Hence, it is possible to analyse practical cases (such as dam–foundation systems) involving initial conditions due to the pre-seismic loads such as water pressure and self-weight of the dam. As an application of the proposed formulation, a gravity dam has been analysed and the results for different foundation stiffness are presented. The results of the analysis indicate the importance of including the foundation stiffness and thus the dam–foundation interaction. 相似文献