Temporal variation of modulated-wave-train geometries and their influence on vertical bending moments of a container ship     

《Applied Ocean Research》2019

A towing experiment was conducted using a modulated wave train to investigate the vertical bending responses of a hydro-structural container ship model. In the experiment, a spatially periodic modulated wave train, as a model of a freak wave in successive high waves mimicking the so-called three sisters, was generated by the recently established higher-order spectral method wave generation (HOSM-WG) method. HOSM-WG enables us to control the location and timing of the maximum crest height in a wave tank. With precise control of the towing carriage, an experiment was conducted in which the timing of the encounters between the ship model and the modulated wave train was accurately determined. The maximum sagging moment (SM) was found to increase in proportion with the encounter wave height. However, because of differences in the relative depth of the fore and aft troughs, the maximum SM is highly variable for a given wave height. The temporal wave-geometry evolution caused the relative trough-depth to vary significantly within a wave period in the vicinity of the maximum crest height. As a result, depending on the encounter timing, the SM varied considerably for a given wave height. The temporal variation of the wave geometry is a robust feature of a modulated wave train and is common between the spatially periodic and temporally periodic modulated wave trains.  相似文献   

横观各向同性岩体中圆形巷道反分析的惟一性   总被引：1，自引：1，他引：0  

张志增  李仲奎 《岩土力学》2011,32(7):2066-2072

惟一性研究是位移反分析的基础工作之一。推导了横观各向同性岩体中圆形巷道的位移解析解,利用参数可辨识条件对横观各向同性岩体中圆形巷道位移反分析的惟一性进行了探讨。结果表明,无论量测多少个点的位移也不能惟一地反演出所有6个参数;必须至少已知3个参数时,才有可能惟一地反演其他参数;2个地应力分量是否相等对反分析结果有明显的影响;2个地应力分量的可辨识性最好,各向同性面上的弹性模量和泊松比次之,垂直各向同性面方向的弹性模量和泊松比最差。  相似文献   

西藏当雄地区拉屋矿床磁黄铁矿Re-Os同位素测年 和成矿物质来源示踪   总被引：1，自引：0，他引：1  

崔玉斌  赵元艺  屈文俊  刘伟  叶荣  刘妍 《地质通报》2011,30(8):1283-1293

拉屋矿床位于西藏自治区当雄县境内,大地构造位置处于冈底斯成矿区申扎-旁多铜、银、铅、锌、金成矿带,为大型矽卡岩型铜铅多金属矿床。在系统研究拉屋矿床地质地球化学特征的基础上,以矿石的磁黄铁矿为对象,测定Re-Os同位素年龄,获得等时线年龄数据为(309±31)Ma,187Os/188Os的初始值为0.51±0.12,γOs值为306.90~880.29,Re/Os为20.46~80.46。上述结果,结合矿区野外地质特征和稳定同位素特征,证明拉屋矿床主要形成于晚石炭世来故期,其成矿物质来源于地幔,并在喷流过程中与地壳海底卤水汇合,遭受了壳源物质的混染,形成喷流成因矽卡岩型矿床。  相似文献   

娄江特大桥深孔泵吸反循环工艺的改进          下载免费PDF全文

张广亮  刘建涛  陈益敏 《探矿工程》2011,38(6):47-50

随着国家基础设施投入的加大,桩径1000－2000 mm、孔深100－130 m的钻孔灌注桩在各类工程中屡被采用。泵吸反循环传统上被用于孔深不超过80 m的深孔,在京沪高铁第六标段娄江特大桥钻孔灌注桩施工中,通过对现有的反循环钻机进行改进,很大程度上提高了泵吸反循环的工作效率,顺利地完成了孔深131 m、桩径1.8 m桩孔的施工,产生了很好的经济效益。  相似文献   

HNCORS在电力工程测量中的应用     

孙建勇  张中原 《测绘与空间地理信息》2011,34(3):121-122,125

介绍了连续运行参考站网系统的有关概念,结合HNCORS系统的建设运行,详细探讨了CORS系统在电力工程测量中的应用.  相似文献   

村镇滑移隔震建筑瞬时摩擦耗能的参数敏感性分析          下载免费PDF全文

孙敏  王锦燕  孙光林 《世界地震工程》2020,(3):100-108

给出了村镇滑移隔震建筑瞬时摩擦耗能的概念，并以此概念为响应指标。通过极差大小的对比，分析了该响应指标对刚度比、第二阶段刚度系数、隔震层屈服位移、隔震层摩擦系数、系统质量比和上部结构自振周期六个参数变化的敏感程度，阐述了上述系统参数对瞬时摩擦耗能这一响应指标的影响规律。研究表明:场地条件和地震动幅值大小对瞬时摩擦耗能均有显著影响；在所考虑的参数范围内，上部结构自振周期总是对瞬时摩擦耗能有较为显著的影响，摩擦系数对瞬时摩擦耗能的影响跟场地条件有关，Ⅰ类场地条件中摩擦系数对瞬时摩擦耗能影响不显著，而Ⅱ、Ⅲ和Ⅳ类场地条件中，摩擦系数对瞬时摩擦耗能的影响则非常显著；隔震层屈服位移、刚度比和第二阶段刚度系数总得来讲对瞬时摩擦耗能影响不显著，质量比对瞬时摩擦耗能影响居中。  相似文献   

3D geological modeling for prediction of subsurface Mo targets in the Luanchuan district,China     

《Ore Geology Reviews》2015

Three-dimensional (3D) district-scale geoscience information for the Luanchuan Mo district was integrated for understanding the development of its regional geology and ore-forming processes and for decision-making about potential targets for mineral exploration. The methodology and datasets used were: (1) construction of an initial geological model (25 km × 20 km × 2.5 km) using 1:10,000 scale geological map, nine geological cross-sections and gravity and magnetic data; (2) construction of three large-scale Mo deposits model (5 km × 4 km × 2.5 km) using 1:2000 scale geological and topographic maps, 288 boreholes (total core length of 158,700 m), and 32 1:2000 scale cross-sections; (3) 3D inversion of 1:25,000 scale gravity and magnetic data for identification metallogenic anomaly zones which are associated with Jurassic intrusions; (4) extraction of ore-controlling formation and sequence of the Luanchuan Group using the large-scale 3D models of Mo deposits and results of analysis of lithogeochemical samples from outcrops and borehole cores; (5) identification of ore-forming and ore-controlling faults using the large-scale 3D model of Mo deposits and mineralized Jurassic granite porphyry stocks; (6) boost weights-of-evidence and concentration–volume (C–V) fractal analyses to integrate metallogenic information and to identify and classify potential Mo targets. Four classes of exploration targets were identified using C–V modeling and 3D known orebodies model: the first and second class targets are mainly located in three large magma-skarn type deposit camps, occupying ~ 1.4 km³ with total estimated reserve of ~ 2.3 Mt; the third class targets, which are mainly located in Huangbeiling and Yuku deposit camps comprising concealed magma-skarn type deposits, occupy ~ 2.8 km³ and represent a new target exploration zone in the Luanchuan district; the fourth class targets, which are located in the Huoshenmiao, Majuan, and Daping zones, occupy ~ 15 km³ and represent potential mineral resources with likely similar orebody features as the Yuku deposit.  相似文献   

河南省三门峡尖草地铝土矿地质特征及成矿演化模式     

李建全  席善峰  赵晓宁  李书文  赵钦  冯建涛  王猛  裴满意 《地质与资源》2017,26(6):564-569

以三门峡尖草地铝土矿床为对象,在研究矿床地质特征的基础上,分析了成矿物质来源、控矿因素,并刻画了成矿演化模式.三门峡尖草地铝土矿床赋矿层位为本溪组,是在沉积间断面、沉积古地理、古构造等多个条件的耦合作用下形成的.该地层后期抬升遭受剥蚀,再沉积形成局部堆积型的铝土矿床.其成矿演化模式在豫西地区具有典型找矿意义.  相似文献   

我国典型资源枯竭型城市生态系统健康综合评价   总被引：3，自引：0，他引：3  

陶晓燕 《地域研究与开发》2010,29(1)

资源枯竭和环境恶化影响着典型资源枯竭型城市的发展。根据"压力-状态-响应"模型,构建了一个度量典型资源枯竭型城市生态系统健康水平的含有4个层次35项具体指标的指标体系,并运用客观的改进的熵值法赋权、模糊综合评价法及划分的等级标准对我国9个典型资源枯竭型城市的生态系统健康水平进行量化分析。结果表明,阜新市的生态系统健康水平属于"较健康"级,伊春、辽源、白银、焦作属于"临界状态"级,盘锦、白山、萍乡属于"较不健康"级,而石嘴山则属于"不健康"级。典型资源枯竭型城市的生态系统健康水平总体上不容乐观。  相似文献   

GPS在机载雷达测速精度鉴定中的应用     

王云河  王存良 《全球定位系统》2010,35(2):5-8

论述了利用GPS来鉴定机载雷达的测速精度，推导了雷达对目标径向的速度基准值计算公式及其精度计算公式，并计算了该速度基准值及其精度，结果表明：能够满足速度基准值精度要求。强调了在做测速精度鉴定方案时，需要计算在被鉴定速度方向上的速度基准值精度是否满足要求。  相似文献