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排序方式: 共有475条查询结果,搜索用时 156 毫秒
51.
海底地貌是海水覆盖下的固体地球表面形态的总称。海底地貌巨变往往与海底地质灾害息息相关,会对海底管线和海上平台等海洋工程设施造成危害,因而对海底地貌进行原位观测具有重要意义。本研究基于前人研究成果和团队常年自主研发仪器经验,研制出了剖面声呐海底微地貌原位观测系统,详细介绍了观测系统的组成、功能、工作原理和工作模式,并提出了观测数据的处理分析方法;然后,使用观测系统进行了标志物检验实验,通过将观测系统测量数据与其他设备测量数据相对比,验证了观测系统的可行性和数据准确性;最后,使用观测系统在舟山海域朱家尖滑坡区进行原位观测,进一步验证了观测系统的可行性。观测结果进一步表明剖面声呐观测系统可以用于海底微地貌的观测研究。 相似文献
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Parameters play a very important and determinative role in the dynamics of a dynamical system as well as in the formation
of its particular characteristics. In this paper we investigate the way in which a large scale variation of the mass parameter,
influences the behavior of a mass-less particle which moves in the vicinity of a ring arrangement of N-bodies. More precisely, we study the impact of this parameter on periodic motions and their characteristics. 相似文献
54.
Terrain Pattern Recognition and Spatial Decision Making for Regional Slope Stability Studies 总被引:1,自引:0,他引:1
George?MiliaresisEmail author Nikos?Sabatakakis George?Koukis 《Natural Resources Research》2005,14(2):91-100
A terrain partition scheme is presented that allows the identification of regions with high landslide risk in natural terrain zones on the basis of geomorphometric criteria from moderate resolution DEMs. The key factor being the terrain segmentation to aspect regions (regions formed by points preserving the same aspect direction) instead of using an artificial regular-grid terrain partition scheme. The study area is in western Greece (NW Peloponnesus) whereas a moderate resolution digital elevation model with spacing 75 m is used. Landslide inventory analysis and knowledge conceptualization identified that the landslide susceptibility of a particular aspect region is high, if the mean elevation is low and the mean gradient is high. Each aspect region was parametrically represented on the basis of its mean gradient and elevation. The domain of each parameter was divided to seven slices (classes) on the basis of the observed density. Subsequent knowledge based mapping identified aspect regions with high landslide susceptibility for the following spatial rule: (a) “mean slope in class 6 or 7” and (b) “mean elevation in class 1 to 5”. Alternatively the rule is expressed as mean slope to be equal or greater than 15∘ whereas mean elevation to be in the range 0 to 750 m. These identified zones correspond to regions where historical landslides occurred (populated coastal areas in the North) as well as to south regions (natural terrain zone) where no landslide record is available, because of the limitations posed by the natural terrain landslide mapping program in Greece. The presented terrain segmentation technique combined to the spatial decision-making process, provided both an object framework for integrating geomorphometric parameters and a method for landslide risk analysis in natural terrain zones. 相似文献
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Sumanta Dandapath Andrew Menezes Bishwajit Chakraborty John Kurian Koppella N. Prudhvi Raju 《Marine Geodesy》2018,41(2):177-200
An assessment of the multibeam sonar data of the central Western Continental Margins of India has been carried out to evaluate the seafloor geomorphology and processes by examining the geomorphological attributes e.g., slope, sediments, structures, etc. associated with geomorphic features. The variation in relief and the features located in the region have been mapped and interpreted collectively by utilizing several geospatial mapping tools. The backscatter strength across the area, apparently congruent with the local relief, has helped to examine the sediment movement on the seafloor. The prominent features found in the region include faults, pockmarks, mounds, submarine terraces, and submerged fossil reefs. Several areas with varying topography engender comparable fractal dimension at short scale breaks, and the probability density functions (PDFs) utilizing backscatter data depicting overlapping classes. The present study highlights how fractals and scale break parameters can be utilized to determine the seafloor processes and associated sedimentological dynamics in a complex geographical environment with strong bottom currents, seasonal upwelling, and faulted structure. The role and impact of the various geomorphic processes on the reworking of sediment movement and the overall progression of the seafloor morphology has been revealed for the first time in this part of the ocean bottom. 相似文献
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雨水入渗对非饱和土坡稳定性影响的参数研究 总被引:57,自引:1,他引:56
很多国家和地区的斜坡失稳与雨水入渗有密切关系。通过参数分析研究可以深化对这种关系的认识和理解,因而对滑坡灾害的预测和预防有重要意义。针对香港地区一种典型非饱和土斜坡,用有限元法模拟雨水入渗引起的暂态渗流场,然后将计算得到的暂态孔隙水压力分布用于斜坡的极限平衡分析。计算中采用延伸的摩尔-库伦破坏准则以便考虑基质吸力对抗剪强度的贡献,研究了降雨特征、水文地质条件及坡面防渗处理等因素对暂态渗流场和斜坡安全因数的影响。数值模拟结果表明:降雨强度、降雨历时和雨型对暂态渗流场及斜坡稳定性有明显的影响;土体的渗透系数,尤其是渗透系数各向异性的影响特别显著;斜坡中相对隔水层的存在以及斜坡防渗护面的效果等因素的影响均不容忽视。 相似文献
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对水下地形、碍航物的搜寻方式已由过去的单一设备探测向多种设备复合探测转变。介绍了多种复合探测的基本方法和特点。通过沉船、飞机残骸和航道扫测实例,证明复合探测可大幅度增强水下地形测量结论和水下失落物搜寻判别的真实性、可靠性,同时缩短了搜寻时问,提高了工作效率。 相似文献
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