深水铺管船托管架疲劳分析及动态监测点选取研究     

闫宏生  王哲  王晓波  陈永訢  孟祥伟 《海洋工程》2018,36(1):107-113

作为S型铺管作业的关键性装备,托管架长期承受着交变载荷的作用,随着海洋开发向超深水发展,结构疲劳破坏问题不容忽视。采用疲劳谱分析的方法并结合线性累积损伤理论,对托管架结构频域下的变形进行了分析,计算了正常海况下和极端海况下托管架疲劳损伤度并对疲劳寿命进行了评估。研究发现托管架在正常海况下作业符合安全要求,在极端海况下局部结构会受到破坏。并从托管架结构安全监测角度,筛选了结构疲劳分析关键点位,为监测点位的选取提供了依据。  相似文献   

青藏高原第一条超深反射地震剖面的数据采集及其处理方法   总被引：1，自引：0，他引：1  

郭景如  蒋多元  唐文榜  赵文津 《地球学报》1996,17(2):202-213

中美ＩＮＤＥＰＴＨ项目第一阶段先导性试验，提供了高分辨率、高信噪比和反射信息非常丰富的近垂直反射剖面。其中主喜马拉雅滑脱界面（ＭＨＴ）和深达７０—８０ｋｍ的Ｍｏｈｏ，清晰可见；Ｍｏｈｏ以下仍有反射信息。事实证明．采用井深５０ｍ、药量５０ｋｇ和５０ｓ超长记录长度３个技术措施后，近垂直反射技术可以取得深部反射信息。在工作中井深和激发岩性是影响记录质量的两个互相依赖的重要因素。资料分析表明．井深大于２５ｍ的单孔爆炸，其记录质量较好，而井深大于２５ｍ组合的炮记录，几乎接收不到深反射信息。钻井所采用的泥浆固井和装炸药后填井等技术措施，对提高记录质量有较大帮助。在地震数据处理工作中，针对激发岩性沿线变化剧烈，我们做了地表子波一致性处理和去噪处理，极大地提高了深反射叠加剖面的质量。  相似文献   

喷涂聚脲弹性体技术在海港码头预应力大管桩上的应用     

李森林  范卫国  史忠裕  王家顺  孙红尧 《海洋工程》2010,28(1)

针对北仑电厂预应力大管桩表面潮湿,需候潮作业,施工条件复杂,施工作业时间短的特点,从表面处理、参数的设定、喷涂施工、质量控制及验收和存在问题及解决方案等方面,介绍了喷涂聚脲弹性体技术在已建海港码头预应力大管桩表面防腐保护工程中的应用情况。可为类似结构物的设计、施工、维护及管理提供参考。  相似文献   

海洋纤维增强热塑性立管极限承载拉力预测方法     

何杨烨  谭健  韩元明  袁坤  刘军鹏  安峰辰 《海洋工程》2024,(3):44-59

海洋新型纤维增强热塑性立管因其可盘卷、耐腐蚀、耐疲劳和轻质化等优点,在深水油气开发中应用前景十分广阔。热塑性立管具有复合材料的各向异性、受力耦合效应及复杂的本构关系,且承受浮体运动和复杂海洋环境载荷,其失效模式尚未明确。针对轴对称载荷作用下纤维增强热塑性立管极限承载力问题,进行热塑性管稳态热传导和热应力的理论推导,求解了稳态温度和应力分布,首次给出了在任意温度载荷作用下管体径向位移的解析解,并直接求解其径向、轴向、环向和剪切应力。采用各向同性层Von Mises和各向异性层最大应力（Max Stress）准则或Tsai-Hill准则判定热塑性管的失效,基于应力分布、失效准则和二分法计算了热塑性管的极限载荷。温度载荷、纤维铺设角度和径厚比对管道的应力分布影响显著。不同温度载荷会改变失效指数沿径向的变化趋势,增大轴向拉力将增大热塑性管的失效指数,选用不同的失效准则在管体失效判定上存在一定的差异。热塑性管温度越低、纤维铺设角越小及径厚比越大,管道对轴向拉伸载荷的承载能力越强。  相似文献   

Lateral dynamic response of a pipe pile in saturated soil layer          下载免费PDF全文

Changjie Zheng  Hanlong Liu  Xuanming Ding 《国际地质力学数值与分析法杂志》2016,40(2):159-184

This paper presents an analytical solution for the lateral dynamic response of a pipe pile in a saturated soil layer. The wave propagations in the saturated soil and the pipe pile are simulated by Biot's three‐dimensional poroelastic theory and one‐dimensional elastic theory, respectively. The governing equations of soil are solved directly without introducing potential functions. The displacement response and dynamic impedances of the pipe pile are obtained based on the continuous conditions between the pipe pile and both the outer and inner soil. A comparison with an existing solution is performed to verify the proposed solution. Selected numerical results for the lateral dynamic responses and impedances of the pipe pile are presented to reveal the lateral vibration characteristics of the pile‐soil system. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

A 3D discrete FEM iterative algorithm for solving the water pipe cooling problems of massive concrete structures          下载免费PDF全文

Jing Cheng  T. C. Li  Xiaoqing Liu  L. H. Zhao 《国际地质力学数值与分析法杂志》2016,40(4):487-508

Water pipe cooling has been widely used for the temperature control and crack prevention of massive concrete structures such as high dams. Because both under‐cooling and over‐cooling may reduce the efficiency of crack prevention, or even lead to great harm to structures, we need an accurate and robust numerical tool for the prediction of cooling effect. Here, a 3D discrete FEM Iterative Algorithm is introduced, which can simulate the concrete temperature gradient near the pipes, as well as the water temperature rising along the pipes. On the basis of the heat balance between water and concrete, the whole temperature field of the problem can be computed exactly within a few iteration steps. Providing the pipe meshing tool for building the FE model, this algorithm can take account of the water pipe distribution, the variation of water flow, water temperature, and other factors, while the traditional equivalent algorithm based on semi‐theoretical solutions can only solve problems with constant water flow and water temperature. The validation and convergence are proved by comparing the simulated results and analytical solutions of two standard second‐stage cooling problems. Then, a practical concrete block with different cooling schemes is analyzed and the influences of cooling factors are investigated. In the end, detailed guidance for pipe system optimization is provided. Copyright © 2015 John Wiley & Sons, Ltd.  相似文献   

An inexpensive and portable drill rig for bedrock groundwater studies in headwater catchments     

C. P. Gabrielli  J. J. McDonnell 《水文研究》2012,26(4):622-632

Bedrock groundwater dynamics in headwater catchments are poorly understood and poorly characterized. Here, we present an inexpensive and portable bedrock drilling system designed for use in remote locations. Our system is capable of drilling bedrock wells up to 11 m deep and 38 mm in diameter in a wide range of bedrock types. The drill consists of a lawn mower engine adapted to rotate a diamond tipped coring bit, a small water pump to cool and flush the drill bit and a scaffolding platform for stable footing on steep slopes. The complete drilling assembly costs under $ 2000 USD. Here, we show proof‐of‐concept of our approach with 40 successful wells drilled in different geological substrates, including a conglomerate at the Maimai experimental catchment in New Zealand, volcanic breccias at the HJ Andrews experimental watershed in Oregon, USA, sandstone and siltstone at the Alsea watershed in Oregon, USA, and basalt at the Los Gavilanes experimental watershed in Veracruz, Mexico. We also present a transparent comparison between our design and other portable bedrock drilling systems and outline the strengths and weaknesses of each system. Copyright © 2011 John Wiley & Sons, Ltd.  相似文献   

地下管线探测的基本原理及解释方法研究   总被引：2，自引：0，他引：2  

封崇德  史保连 《物探与化探》1994,18(6):463-467

本文较详细地讨论了电磁直接探测法探测地下管线的基本原理和解释方法;提出了一种新的求解管线位置和深度、并给出探测结果可信度的向量交绘法。现场提供高可信度的结果;对管线探测仪器设备及应用效果作了介绍。  相似文献   

冲击反循环工程钻机自动同步机构的原理          下载免费PDF全文

喻重山  孙孝庆 《探矿工程》1994,(4):1-3

采用行星齿轮差速机构作为ＧＣＦ－１５００型冲击反循环工程钻机的自动同步机构，已经获得成功。分析了该机构的运动学原理和力平衡原理。该机构具有结构简单、工作可不的特点。  相似文献   

地层压力和大直径套管抗挤压力计算   总被引：2，自引：0，他引：2  

张平占  叶礼明 《煤田地质与勘探》1995,23(1):62-66

介绍了上覆地层压力和粘土吸水膨胀对套管挤压以及大直径管受外挤力失稳破坏的计算方法。解决了现场遇到的实际问题。  相似文献