A Study on Impervious and Heat-Insulating Performance of Geomembrane Composites Within Breakwater

This paper investigates the performance of geomembrane composites used as impervious andheat-insulating lining within a breakwater for a power station.The seepage field,distribution ofstress-strain contour and seepage discharge of hot water which has been treated as the inner thermalsource in the calculation of heat-insulation,have been given by three-dimensional calculation method coup-ling seepage with stress.The results indicate that the impervious and heat-insulation effect ofgeomembrane composites is significant.     

Investigation on the Performance of Articulated Buoys

Articulated buoys become more and more popular by the marine management departments as a new type of aids to navigation, for they possess an excellent hydrodynamic performance with small static heel angle in wind and current and small rolling in wave and accurate position. The structure of articulated buoys and calculation method of their hydrodynamic performance are introduced in this paper. A scries of experiments has been conducted in the State Key Laboratory of Ocean Engineering of China and useful results achieved for providing a design optimization basis.     

Evalution of Application of p-y Curve Method in Offshore Engineering Foundation

- Based on the Mohr-Coulomb failure principle and Rankine's theory, the laterally loaded pile ultimate resistance formulas of sand and soft clay proposed by Reese and Matlock respectively are discussed in this paper. The authors put forward the modified ultimate resistance formulas on the basis of which the ultimate resistance formula is developed for horizontally loaded pile in multi-layer soil in consideration of the effect of the overburden soil pressure on the calculation of soil layer. It is significant to the correct application of the ultimate resistance formulas in API and ZCS Rules into offshore engineering.     

Simulation and Analysis of a Gravity Cyh''''nder''''s Stability in Short-Crested Sea

Generally, the reliability of ami -sliding and anti-overturning stability of an isolated gravity cylinder in a certain working period can be evaluated only when the statistical properties of short term stability are given first. The authors used numerical method to simulate the stability state function of a cylinder in short-crested sea, and further to get the probabilitical characteristics of the structure's stability by time domain analysis. The external loads appeared in the state functions include horizontal wave force, lift force and the respective moments, and the loads are correlated by co- spectrum. The numerical method presented in this paper can be used not only to solve short term reliability problem directly, but to calculate and analyse the long term reliability problem as well. For circular cylinders, an example of simulation and analysis is displayed in this paper.     

Determination of Shaft Capacity for Pile under Cyclic Axial Loading in Clay

For load-controlled and displacement-controlled test data of piles cyclically axially loaded in clay, the displacement conditions are suggested for determining the shaft capacity. According to the suggested displacement conditions, not only the results of shaft capacity from laboratory model piles are close to those from in-situ piles, but also the results of load-controlled tests are in satisfactory agreement with those of displacement-controlled tests. Moreover, based on the test data of laboratory model piles in combination with the test data published, the paper suggests the values of the normalized shaft capacity of piles under a variety of static and cyclic loading combinations.     

Experimental Study on Rectangular Floating Breakwaters

This paper proposes ten types of improved floating breakwaters for experiment with regular waves, based on the experience in the development and manufacture of existing floating breakwaters both at home and abroad, and on the results of experimental studies on the hydraulic characteristics of several types of floating breakwaters. The wave heights before and behind the breakwaters are measured, the movements of floating breakwaters are observed and the chain forces of the floating breakwaters are measured. The paper studies and compares the hydraulic characteristics of the improved rectangular floating breakwaters of which the internal and external structures and their installation methods are changed. Finally the optimal type of structure is selected through experiments.     

Investigation on Settling Characteristics of Floes in the Changjiang Estuary, China

- Settling characteristics of floes, including relative settling velocity, relative flocculation coefficient and flocculation exponent, are obtained by the suspended load equations for different size fractions. Data of the Changjiang Estuary suggest that level of flocculation changes from river section, river mouth (turbidity maximum) to offshore area in sequence of low, very high and high. The settling characteristics of floes reflected by in situ estimation performs a similar feature as that obtained from still water experiment.     

Structural Vibration Mode Re-Analysis of Offshore Structures

-This paper reviews the current methodology for dynamic reanalysis. Rayleigh-Ritz approach and receptance approach are discussed in detail. Based on a general finite element structural analysis program SAPS, an eigenproblem re-analysis prorgram ERP was compiled. With a very small change the program can be implemented readily with any general FEM program. Finally, some numerical examples show that the new algorithm is of high precision and efficiency. In the case of local modification in the offshore platform, the efficiency is raised by 20- 50 times when compared with the re-calculation of the whole model.     

Brief Account of Breakwater Construction in China

-The construction of breakwaters in China in more than 40 years since the founding of the People's Republic of China is reviewed. The construction of two main types of breakwater, upright breakwaters and rubble mound breakwaters, and the way in which they are built are expounded. Recommendations to improve the technology for future breakwater construction are presented.     

Stochastic Response Analysis of Piled Offshore Platforms to Earthquake Load

- In this paper, using the theory of stochastic analysis of the response to earthquake load, a stochastic analysis method of the response of piled platforms to earthquake load has been established. In the method, the strong ground motion is considered as three dimensional stationary white noise process and the pile-soil interaction and water-structure interaction are considered. The stochastic response of a typical platform to eqrthquake load has been computed with this method and the results compared with those obtained with the response spectrum analysis method. The comparison shows that the stochastic analysis method of the response of piled platforms to earthquake load is suitable for this kind of analysis.