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61.
1:25万区域地质调查修测的核心任务是挖掘、利用前人资料和对前人资料的二次开发。在1:25万玉林市幅数字地质填图试点的过程中.总结出一套基于数字填图系统的前人地质资料利用与数据采集的工作方法。其工作流程和工作步骤可分为6个阶段:①前期准备阶段;②室内地质资料录八阶段;③野外数字地质调查阶段;④室内资料整理阶段;⑤图件编制阶段;⑥成果提交阶段。该工作方法与传统的地质调查方法相比,提高了地质调查的工作效率和质量,已基本上达到了在1:252万区调修测区推广应用的“实战性”要求。 相似文献
62.
RTK技术在杭州湾跨海大桥桥位地形测绘中的应用 总被引:1,自引:0,他引:1
介绍了RTK技术在杭州湾跨海大桥桥位地形测绘中的应用,并对其定位结果进行了精度比较与分析,结果表明:RTK定位测量的点位精度可达厘米级,各点位之间不存在误差积累,与全站仪等测量手段取得的结果符合得较好,可以用来代替二三级导线控制测量和等外水准等测量方法;流动站与基准站的距离在10km范围以内时,应用RTK技术对近岸水下地形进行测量具有方便、快捷、精度高等特点,但当此距离超过10km时,其精度则难以保证。杭州湾跨海大桥施工时应用RTK技术进行定位、高程测量,可提高工作效率和成果的质量。 相似文献
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AbstractThe ground vibrations during pile driving operation have a drastic potential to undermine the surrounding structures both in land and reclaimed land. Particularly, reclaimed land necessitates ample application of pile driving due to the weak land condition. To prevent the structural damage, attenuation of the ground vibrations to an allowable level through active isolation of circular open trench is the scope of this study. In this research, finite element simulations of continuous impact pile driving process from the ground surface was executed with particular attention to the pile-soil interaction, and thereby, the efficiency of open trench application in attenuation of the unsafe distance of different structures was surveyed using the vibration sensitivity degree. Regarding the crucial parameters of an open trench (depth, width, and location), it was concluded that a sufficient high depth can attenuate the unsafe distance up to 68%, the trench width variations are less effective, and an average pile-trench distance is the most efficient option. The excavation volume was also concluded as another crucial parameter in open trench design which takes all three parameters into account. The trench depth equal to the pile’s maximum critical depth of vibration was inferred for an optimum design. 相似文献
65.
在分析综合辽宁省海岸带调查和沿海经济贝类污染监测资料基础上,根据辽宁海岸带水质,沉积物和生物污染现状及发展趋势。针对所存在的问题,讨论了辽宁省海洋污染特别是赤潮对海洋资源的破坏,并在组织机构,地方立法,海岸带环境保护规划,污染源控制与整体环境改进,监测方案等方面提出了建设海上辽宁、加强辽宁省海洋环境保护与海岸可持续开发利用的建议。 相似文献
66.
INTRODUCTIONTheOkinawaTrough (OT) ,locatednorthwestoftheRyukyuTrenchandtheRyukyugunto ,eastoftheEastChinaSeashelf,isaback arcbasinbulgedtotheRyukyuTrench .TheOTextendsfromKyushuinthesouthwestofJapantotheIlanPlaininthenortheasternTaiwan ,Chinainthesouthwest… 相似文献
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Environmental control of growth and BChl a expression in an aerobic anoxygenic phototrophic bacterium, Erythrobacter longus (DSMZ6997) 总被引:1,自引:0,他引:1
1Introduction Aerobic anoxygenic phototrophic bacteria(AAPB) are facultative heterotrophs that can utilizelight for photosynthesis. These unique-functioningbacteria are widely distributed in marine environ-ments, such as coastal waters (Shiba et al., 1991… 相似文献
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Lodolo Emanuele Coren Franco Schreider Anatoly A. Ceccone Giulio 《Marine Geophysical Researches》1997,19(5):439-450
The southwestern part of the Scotia Sea, at the corner of the Shackleton Fracture Zone with the South Scotia Ridge has been investigated, combining marine magnetic profiles, multichannel seismic reflection data, and satellite-derived gravity anomaly data. From the integrated analysis of data, we identified the presence of the oldest part of the crust in this sector, which tentative age is older than anomaly C10 (28.7 Ma). The area is surrounded by structural features clearly imaged by seismic data, which correspond to gravity lows in the satellite-derived map, and presents a rhomboid-shaped geometry. Along its southern boundary, structural features related to convergence and possible incipient subduction beneath the continental South Scotia Ridge have been evidenced from the seismic profile. We interpret this area, now located at the edge of the south-western Scotia Sea, as a relict of ocean-like crust formed during an earlier, possibly diffuse and disorganized episode of spreading at the first onset of the Drake Passage opening. The successive episode of organized seafloor spreading responsible for the opening of the Drake Passage that definitively separated southern South America from the Antarctic Peninsula, instigated ridge-push forces that can account for the subduction-related structures found along the western part of the South Scotia Ridge. This seafloor accretion phase occurred from 27 to about 10 Ma, when spreading stopped in the western Scotia Sea Ridge, as resulted from the identification of the marine magnetic anomalies. 相似文献