Discussion on Cathodic Protection of HZ 21-1 Platform     

Chen Lisheng Engineer  Nanhai East Oil Corporation. CNOOC  Guangzhou 《中国海洋工程》1992,(2)

The environmental conditions around the first offshore HZ 21- 1 steel wellhead platform in the South China Sea are characterized by deep water, frequent typhoons, rough waves, high water temperature, severely corrosive seawater, and thick fouling organism attachments. The design and effectiveness of galvanic anode protection system are presented, and several methods are described, which are the calculation method of the protective current density considering the variation of water depth, the method of determining protection parameters considering various factors, the arrangement of anodes based on potential distribution and current requirements at different water depths, and the method of anode installation. Finally the effect of the accuracy of selected cathodic protection parameters on the economic benefits of offshore projects is also discussed..  相似文献   

Qualification Test for the Reliability of Diver Gas Recovery System     

Mao Fangguan  Lu Shunchang  Luo Ruiren Senior Engineer  The Naval Medical Research Institute  Shanghai . Senior Engineer  The Navigation Guarantee 《中国海洋工程》1997,(3)

A qualification test for the reliability of a newly-developed Diver Gas Recovery System(DGRS)was carried out in the Naval Medical Research Institute of the People's Liberation Army,Chinafrom March 29 to April 2,1995.A sequential test plan of high discrimination ratio for the mean time be-tween failures(MTBF)was adopted.The test procedures simulated those of a 300 msw dive.A hyperbaricbreathing machine was used for the simulation of diver's respiratory functions.Parameters,such as divingdepth,respiratory minute volume(RMV),CO_2 production,gas flow rate,partial pressure of carbondioxide,and ambient temperature and himidity were all displayed and recorded with a microcomputer sys-tem.The results indicated that no failure occurred during the 91.5 h operation.According to the accept-ance and rejection criteria specified in the statistical test plan,a no-failure score in the 88 h operation is ac-ceptable.Therefore,the DGRS has been demonstrated to meet the requirements of MTBF specified in thecontract.  相似文献   

Numerical Study of Oil Pollution on Sea Waters     

Geng Zhaoquan  Ni Yongqiang  Zhou Anguo Senior Engineer  Zhejiang Provincial Institute of Estuarine  Coastal Engineering Research  Hangzhou Engineer  Zhejiang Provincial Institute of Estuarine  Coastal Engineering Research  Hangzhou Engineer  Zhejiang Institute of Environmental Protection Science  Hangzhou 《中国海洋工程》1992,(1)

This paper adopted an upstream FEM of 2-D unsteady flow to calculate the tidal flow in Zhoushan sea area. Based on the verification of the tidal current and environmental situation, the effects of the oily waste discharged from the oil berths on water quality have been calculated with a similar method. The isodilutions of oil pollutant are drawn from different sewage discharges. The moving loci of the slick centrepoint of oil spill have been calculated. The spreading area of the oil spill has also been forecasted. The results indicate that the set of models can predict the transport of oil spill in the sea area with reasonable accuracy.  相似文献   

Test Study on Erosion and Siltation Patterns of Sandy Bottom Before Mound Breakwater Under the Effect of Waves     

Zhang Furan  Wang Huaren Zhao Jun Assistant Researcher  Tianjin Research Institute of Water Transport Engineering    Tianjin Assistant Engineer  Tianjin Research Institute of Water Transport Engineering    Tianjin 《中国海洋工程》1992,(4)

In this paper, the effect of waves on erosion of the sandy bottom before mound breakwaters is studied. The sandy bottom basically presents two erosion patterns, between which there is a transitional state, under the action of partially standing waves. The two erosion patterns can be determined by dimensionless parameter Us, defined in this paper. The erosion locations, depths and lengths can be estimated by a series of equations presented in the text. Irregular waves are employed in the test besides regular waves, and the effect of the irregular waves can be estimated by the element of equivalent waves, such as T1/3, H1/3.  相似文献   

Dynamic Load Identification in Time Domain   总被引：1，自引：0，他引：1  

Chu Liangcheng  Qu Natsi  Wu Ruifeng Lu Min  Yang Guojin Assistant  M. S.  Dalian University of Technology  Dalian Associate Professor  Dalian University of Technology  Dalian Professor  Dalian University of Technology  Dalian Engineer  Bohai Oil Company Senior Engineer  Bohai Oil Company 《中国海洋工程》1991,(3)

- In the time domain method the dynamic load is successfully identified when the accelerations, velocities and displacements or velocities and displacements of the structure are known. But in engineering practice or experiments usually only the acceleration response is recorded. In this paper an improved time domain method is proposed for dynamic load identification. In this method by using of Duhamel integral, only the acceleration response is required for load identification. As an application of the present method, the dynamic ice load on a Bohai offshore platform is identified based on some measured acceleration. The identified values of ice load are in good agreement with the measured ones.  相似文献   

Investigation of Performance of Turret Assembly in Inboard Turret Mooring System     

Ma Peisun  Ma Lie  Lu Shunshou Associate Professor  Shanghai Jiaotong University  Shanghai Graduate  Shanghai Jiaotong University  Shanghai Engineer  Shanghai Jiaotong University  Shanghai 《中国海洋工程》1991,(4)

To fulfil the need of development of offshore oil floating production system, the performance of turret assembly in an inboard turret mooring system has been investigated in the paper. By means of systematic evaluation, the optimal structure of the turret for single-point mooring systems has been determined. Through model tests of a turret mooring system, several groups of data such as forces, moments and displacements under different environmental conditions have been obtained. Stresses and strains of the turret structure have been calculated by means of the finite element method corresponding to the situation in the model experiment. The study shows that the selected turret structure and the designed turret assembly are technically feasible.  相似文献   

Application of Explosion Method to Soft Foundation Treatment of Great-West Dyke,Lianyungang Port     

Liu Huairen Engineer  Fifth Engineering Company  Third Navigational Engineering Bureau  The Ministry of Communications  Lianyungang 《中国海洋工程》1995,(2)

Explosion for the treatment of underwater soft foundation is a technique newly developed in China. This paper describes the application of the method of explosion to underwater soft foundation treatment of the Great-West Dyke, Lianyungang Port, including the technical characteristics and the effect, selection of explosion parameters, workmanship of construction, requirements of quality and inspection, and the like.  相似文献   

Design of Distorted Wave Protection Armor Units     

Lou Hongen Senior Engineer  Nanjing Hydraulic Research Institute    Nanjing 《中国海洋工程》1992,(4)

In consideration of the global optimization for engineering projects, a group of calculation formulas have been derived by means of theoretical derivation and model tests. On this basis, a design procedure for the distorted units is proposed, by means of which the distorted units of an anology shape and an identical porosity ratio with the original units can be obtained after conducting a distorted enlargement and a normal contraction. The stability waveheight and stability factor of the distorted unit can be calculated with the enlargement factor, a, of the horizontal dimension of the distorted unit, or with the contraction scale, A , of the contracted distorted unit. As a result, the stability of the armor unit can be significantly improved without increasing the quantity of concrete. For the same wave met by the original units, the thickness of placement of the contracted distorted unit can be obviously reduced, thus, a large quantity of concrete can be saved, consequently, economic benefit can be achieved.  相似文献   

Probabilistic Analysis for Seismic Stability of Beach Earth Embankment     

He Guangne Yang Bin Professor  Dalian University of Technology  Dalian Engineer  Design  Research Institute of Shanghai Harbour Engineering  Shanghai 《中国海洋工程》1995,(4)

The current safety factor method for evaluating earth embankment stability is not very rational since the assessment of slope stability is really an uncertainty problem. In order to consider the random property of this problem, the probabilistic analysis is introduced herein. Finally, the stability of a real beach earth embankment is analysed by means of the suggested probabilitic approach. It may be seen that the results of analysis can represent the numerical assessment of the degree of seismic stability.  相似文献   

Model Study of Permeable Caisson Breakwater with Slanting Slabs     

Wang Jianyi Ge Zhijin Senior Engineer  River  Harbour Department  Nanjing Hydraulic Research Institute  Nanjing 《中国海洋工程》1993,(2)

- This paper describes the design of a permeable caisson breakwater with slanting slabs (Types I and 11) and presents some preliminary experimental results, together with relevant figures and tables. Analysis is made of the reflection coefficient, transmission coefficient, acting wave pressures, water jetting at the crest of the breakwater, and wave overtopping. Experiments show conclusively that this type of breakwater has the advantages of light dead weight, good wave-absorbing performance, low coefficients of reflection and transmission, and small wave overtopping.  相似文献