海洋工程中桩身自由站立稳定性影响因素分析     

刘润  闫澍旺  毛永华  闫玥  禚瑞花  樊之夏 《海洋工程》2006,24(3):6-13

由于海洋工程中的钢管桩具有直径大、桩壁薄和超长的特点,桩的自由站立稳定性分析是桩基设计的重要组成部分。结合海洋工程的设计实例,借助三维非线性有限元分析方法,考虑桩身变形的几何非线性特性,研究了桩身倾斜度、支撑情况以及水平荷载等因素对桩身自由站立稳定性的影响规律,并将线性分析方法和非线性分析方法得到的结果进行了比较。  相似文献   

Geometries and mechanism of folds in sediments on the southern Huanghai Sea shelf     

LI Xishuang  LIU Baohu  ZHAO Yuexi  LI Sanzhong 《海洋学报(英文版)》2006,25(4):23-31

1Intraduction Foldsinconsolidatedstrataareoftendocumen ted.Butfoldsinloosely consolidatedsedimentsare rarelydiscussed,probablybecauseofthefollowings:(1)folddeformationsinloosely consolidatedsedi mentsareweakortheyhavebeendestroyed;(2)tectonicactivityhasbe…  相似文献   

A major change in the phytoplankton of a Swedish sill fjord—A consequence of engineering work?     

H.L. Filipsson  G. Bjrk  R. Harland  M.R. McQuoid  K. Nordberg 《Estuarine, Coastal and Shelf Science》2005,63(4):551-560

A major phytoplankton change occurred during the late 1930s and early 1940s in Koljö Fjord, a sill fjord on the Swedish west coast. Dinoflagellate cyst concentrations increased tenfold over a short period of time, from hundreds of cysts per gram sediment to thousands; and the species composition of both dinoflagellate cysts and diatoms changed markedly. These changes took place during a period of extensive engineering work at the entrance to the fjord from the Skagerrak. At this time, the entire passage was straightened, a new channel was built in a previously shallow area, and the old connection was closed. This study investigates whether this engineering work could have sufficiently altered the surface-water circulation to bring about the change in the phytoplankton composition. Several mechanisms are explored by which the construction could have influenced the phytoplankton in the fjord. The primary mechanism is probably increased efficiency of tidal-generated surface-water exchange in the fjord, resulting in a larger transport of surface water from the Skagerrak and consequently a changed surface-water environment. This study highlights how engineering work can have a substantial impact on the local and regional marine environment, a factor that must not be overlooked in environmental planning.  相似文献   

临海工程建设对厦门北面海域底质粒级组成的影响     

蔡锋  陈承惠 《台湾海峡》1992,11(1):2-7

本文根据1980年厦门港湾底质调查的70个样品,应用R型因子分析方法,对沉积物粒级组成的成因进行分析。结果表明,该海域陆续修建的临海工程对其沉积物组成影响明显,使其由粗粒组成向细粒组成变化。尤其是高集海堤的兴建,泥沙大量淤积;海堤建成后,沉积环境日益稳定,接受沉积物以粉砂、粘土占主导地位。  相似文献   

土地整治项目科技化管理的探索研究          下载免费PDF全文

王燕鹏  巩玉虎  赵跃伦  张黎芹 《山东国土资源》2018,34(3)

目前,国内土地整治项目管理工作已趋入正规化,各项制度建设较为完善,但普遍存在项目规划设计调查不充分,实施难以有效监管,设计目标完成情况难以落实,档案管理难以规范等不足之处。为转变传统的土地整治低效管理模式,提高管理效率,实现项目管理模式的专业化、精准化、高效化。基于"互联网+"与地理信息系统技术,创新土地整治项目管理模式,在国内首次开发了包含移动巡查填报、移动端采集监管、土地综合项目巡查监管展示和土地综合项目动态监管四大功能模块的土地综合项目动态监管系统,突破了办公环境的限制,实时传输项目的信息,接受社会的广泛监督,减少人工作业条件下的人为干扰因素,科学考核土地整治工作,实现对土地整治项目的高效监管,促进土地资源保护和合理利用。  相似文献   

Measured and calculated spudcan penetration profiles for case histories in sand-over-clay     

《Applied Ocean Research》2019

This paper reports five case histories of jack-up rig installation in layered soil profiles where a dominate feature was a stronger sand layer overlaying a weaker clay layer. In all cases a relatively continuous load-penetration profile was measured during installation of each of the three spudcan foundations. Summary site-investigation data is provided and consisted of mainly torvane, minature vane, unconsolidated undrained triaxial and pocket penetrometer tests for determining undrained shear strength of the clays and blow counts for deriving the relative density of sand. A statistical averaging method recommended in the InSafeJIP guidelines was used to provide the best fit of the undrained shear strength profile in the clay as this then allowed for spudcan load-penetration profiles to be estimated without introduction of user interpretation or bias. Sand properties were taken as provided in the original site-investigation report. Comparisons between load-penetration profiles calculated using the industry-standard ISO guideline, more recently proposed mechanism-based calculation method and three-dimensional large deformation finite element simulations are made with the measured data, leading to valuable insights for practitioners for estimating behaviour of jack-up installations in problematic sand-over-clay soil profiles.  相似文献   

渤中34-2油田复合射孔事故初探     

张飞  李君宝  王晓龙  金鑫  张彬奇  陈欣  徐鲲 《海洋地质译丛》2010,(2):100-104

渤中34-2油田P10井为一口调整井,属于正常温度、压力系统,孔隙度较低,近井带污染比较严重,完井射孔方式采用复合射孔。针对射孔作业中出现减震器上端油管挤瘪、RTTS封隔器水力锚和胶筒损坏、点火棒卡于封隔器芯管内等现象,从管柱设计、负压选择、管柱材质、现场施工管理等方面对此次事故进行分析,并提出相关建议,对射孔作业中类似事故的应对及处理有一定的指导意义。  相似文献   

二十一世纪城市地质工作的思考     

葛双成 《浙江国土资源》1999,(2)

本文阐述了城市地质工作的历史发展，着重论述了城市地质工作的内容，进而对城市地质工作的思路、方法和组织管理提出了设想。  相似文献   

参数方程法确定线路放样中边桩坐标          下载免费PDF全文

刘卉卉  覃辉  赵福君 《海洋测绘》2008,28(2):44-47

给出了线路放样过程中确定中边桩坐标的新方法。根据曲线模型，找出线路控制坐标系与局部坐标系坐标之间的参数方程关系，推出了缓和曲线及圆曲线中、边桩坐标的参数方程，代入已知量求得参数的值，且给出了求解步骤。该方法思路清晰，具有一次转换计算就可以实现获取线路中边桩测量坐标的优点，便于工程应用。  相似文献   

岛礁工程海水拌养珊瑚礁、砂混凝土修补与应用研究   总被引：1，自引：0，他引：1  

陈兆林  孙国峰  唐筱宁  柳玉良 《海岸工程》2008,27(4):60-69

对用海水拌养珊瑚礁、砂混凝土修补与抢修远离大陆的岛碾损坏工程进行应用研究和调研，对该种混凝土的原材料和物理力学性能进行检测，研究了修补界面剂的配合比与修补工艺以及操作方法，并进行了海水拌养珊瑚礁、砂混凝土与海水拌养普通混凝土修补的粘结强度对比测试和海水拌养快凝快强混凝土快速抢修的工程应用实践检验，为岛礁工程修补和抢修提供技术参考资料。  相似文献