Applied Mechanics and Materials Vols. 170-173

Abstract: How to estimate the modal parameters (including natural frequencies and mode shapes) of an offshore platform accurately is crucial for the health monitoring problems. The purpose of this paper is to identify the modal parameters of a physical jacket-type platform model from measured modal testing data using Prony’s method. In the modal testing, the identified false modes are unavoidable and bring much difficulty to determine the accurate modal parameters. To solve these problems, in this paper, the Modal Phase Collinearity (MPC) and Modal Assurance Criterion (MAC) are applied to distinguish the true and false modal. The measured data are extracted from a physical model of a realistic offshore platform. And the results demonstrate that the modal parameters of the first two modes of each direction can be accurately estimated by using the proposed method.

Abstract: A two dimensional semi-implicit finite volume free-surface ocean model(FVFOM2D) based on unstructured C-grid is built, in which the momentum equation is discretized on the faces of each cell, the continuity equation is discretized on the cell. The model is discretized by semi-implicit finite volume method, in that the free-surface is semi-implicit and the bottom friction is implicit, thereby removing stability limitations associated with the surface gravity wave and friction. The remaining terms in the momentum equations are discretized explicitly by integral finite volume method and second order Adams-Bashforth method. The performance of the present model to simulate tidal flow in a geometrically complex domain is examined by simulation of tidal currents in Pear River Estuary.

Abstract: A study was made into the resistance in frost-thaw cycles and chloride penetration of silica-fume concrete by simulating the characteristics of the marine environment and using the R-value evaluation method. The results show that as a result of mixing silica fume in concrete, the R-value increases by 52.1%; the composite use of silica fume and air-entraining agent with an adequate mixing amount can increase substantially the comprehensive property of concrete in resisting frost-thaw cycles and chloride penetration, with the magnitude of R-value increase being as high as 174%~ 284% and the silica mixing amount being best at around 10%.

Abstract: The doppler velocity apparatus of the data collected on the corners river water cut stress in the system were studied. According to the test data, this paper analyzes the different working conditions river bend by shear stress, and draw a conclusion

Abstract: A study was made from both macro and micro aspects into the resistance in frost-thaw cycles and chloride penetration of silica-fume concrete by simulating the characteristics of the marine environment and using the R-value evaluation method, MIP and SEM experiments. after concrete is under frost and thaw cycles by the erosion of seawater, the levels of the most probable pore radius and total porosity have a certain law of varying with the level of R-value, among which, an obvious relation of correspondence in a inverse proportion exists; the concrete mixed with silica fume has a poor ability of SO4²⁻ penetration resistance; the amount and types of superficial and internal corrosive products can reflect the reason of difference in concrete R-value, that is, when the R-value is high, the amount and types of superficial corrosive products are more than that of internal corrosive products. MIP and SEM micro analytical results can prove the macro conclusion of R-value evaluation method.

Abstract: Under the steady and uniform state, the sediment concentration profile of Van Rijn can be deduced. However the formula of Van Rijn is a piecewise function. It is modified by a unification method, and a continuous sediment concentration distribution formula is obtained. The profile of sediment concentration agrees with the field data of Rizhao and Zhoushan.

Abstract: The embankments dwellings in southeast of Henan Province have significant geographical characteristics and the uniqueness of which mainly reflected in the pattern construction of “inhabit by the water”. The formation of this kind of residential morphology is the result of long-term comprehensive effects of various factors, such as historical cultural heritage, molding of physical geography and climate conditions, as well as timing. It can not be realized overnight. The making of embankments dwellings reflects a series of plain ecological coping strategy and manifests unique regional experience of human settlement construction.

Abstract: Rapid industrialization and urbanization development had brought a serious challenge for coastal zone in China. A coastal management model had been set up for coastal zone, the coordination degree and coordinated development model were adopted to analyze the development trend. The results show that the gap between the environment comprehensive efficiency index and economic efficiency index is getting bigger and bigger for Bohai Bay coastal zone.

Abstract: This paper aims to study the hinterland relevant to container port to provide theoretical reference for macroscopically layout and scale building of port. First we analyze competition characteristic and actuality of container port and the relationship between port and its interrelated hinterland. Second, we dissertate the necessity to estimate hinterland range of port and discuss a serious theoretical argument about port hinterland, and then after analyzing actual each method of partition port hinterland, we calculate hinterland occupancy rate of each container port in Liaoning province in China based on p–choice probability and the optimal path-searching algorithm and analyze relevant result. As last we obtain the conclusion that container scale building should according as it’s interrelated hinterland scale in the whole transport network, not any other factor, to avoid enormous invest waste that is brought by blind competition.

Abstract: Hydraulic fill silty sands in Caofeidian port serves as the research object. Through a large volume uniaxial compression test of dredger fill silty sand, the stain-time curves under various levels of normal stress are obtained. The charts show that stain-time curves are all with similarly shaped nonlinear characteristics. The results of tests illustrate that dredger fill silty sands show some creep behavior. In general, the creep process can be divided into three stages: instantaneous deformation, rapid deformation and slow deformation. In addition, normal stress has an evident impact on consolidation-creep behavior of dredger fill silty sands. Initial deformation and final deformation grow larger and larger with an increasing normal stress. In the meanwhile, the time of achieving stable deformation becomes longer as well. Based on the achieved creep charts, a power function is proposed to describe the relationship of deformation-time for the dredger fill silty sands.