Applied Mechanics and Materials Vols. 744-746

Abstract: The paper introduces the distributed temperature sensor (DTS), analyzes the system veracity and the concrete temperature change compared with the conventional thermometer, shows that DTS can fast and accurately monitor the temperature of the dam and provide messages for the construction. It has great value in engineering application.

Abstract: In this study, erosion mitigation by submerged breakwater with artificial reefs is investigated among other means of countermeasures. Beach erosion mechanism near the submerged breakwater and the performance of artificial reef blocks are analyzed in the laboratory. Two-dimensional and three-dimensional laboratory experiments are applied to the analysis. The results of two-dimensional experiments prove that new artifi-cial blocks showed a better performance than the existing blocks in terms of wave attenuation due to wave breaking turbulence near the crest of the structure. Three-dimensional experiments show reduced return flow velocity by half by installing another type of new artificial block in between submerged breakwaters. Return flow has been creating vulnerability in countermeasures by submerged breakwater. Therefore, artifi-cial reef blocks suggested by this study offer solutions to the existing mitigation problems with submerged breakwater.

Abstract: The impact process of 50000t ship and steel sheet pile bulkhead is simulated by finite element software ANSYS/LS-DYNA. This article acquires the impact force-time curve, equivalent force-time curve of steel sheet pile and the pressure-time curve of breast wall. Comparing the impact force of numerical simulation with the result of ship-bridge collision specifications, and general rules and characteristics are obtained. At the same time, put forward some measures to prevent the damage of wharf structure under the ship of large velocity impact, which provide theoretical references during the design, maintenance, and transformation of similar wharf.

Abstract: With the development of steel sheet pile bulkhead gradually toward large-scale and deep water, natural conditions become worse and structural load rating continues to improve, design and construction of steel sheet pile bulkhead needs higher requirements. Then the stability of sheet pile bulkhead under horizontal loads becomes particularly prominent. This paper presents the displacement and stress of steel sheet pile bulkhead structure under different horizontal loads using ANSYS, which provide academic support for the design and construction of steel sheet pile bulkhead.

Abstract: Flexible berthing pile-high pile wharf is a system which is composed of flexible berthing pile, rubber fender and pile platform. The system was divided into two forms based on the pile platform sustained the impact load or not. The method to analysis the lateral deformation of the pile was relatively mature when the platform was subjected to the impact load. Instead, when the pile platform is subjected to the impact load, the analytical method is unsatisfactory because of the complexity about the lateral deformation of the system. This paper takes the second condition as the research object, and study the lateral deformation of the pile, rubber fender and the pile platform. The mathematical formula is built on the horizontal force balancing condition and displacement coordination at the top of pile, the method to evaluate the correlation coefficients of the formulas is suggested, and the steps that solve the formulas by iterative method are described. The theory is clear, and the result can offer a reference for structure design and code revision.

Abstract: Scarce natural resources make it imperative for Korea to exploit nuclear power plant technology to supply energy for industrial purposes not to mention for everyday usage. Korea’s nuclear power plant started when Gori Nuclear Plant started its operation in 1978 and as of today, there are 4 nuclear plants nationwide including the Gori Nuclear Plant, making up 38.2% of all of Korea’s energy supply. Since ‘waste heat’ is generated as a result of plant operation, sea water is needed for cooling purposes and therefore plants are situated near coastal areas. However, the effect on the coastal area such as erosion, deposition, and siltation from the construction of the plant itself is subject of continuing controversy and another being the effects on the coastal environment from warm water that is produced after the cooling process. Generally, topographic change is maintained in equilibrium by the tidal currents’ reciprocating motion in the coastal areas where there are dominant tidal currents. However, artificial action on the current flow for operating a nuclear plant operation at the intake and the outlet breaks the equilibrium of the tides and this in the end results in disturbing the equilibrium condition of bottom topography. This research used the results of long term investigation data of water depth and data of flow discharge conducted inside the intake to investigate erosion and the change in siltation at the intake of the nuclear power plant. After having analyzed the changes in water depth of the intake area, the results confirmed that there are 100~140cm/year and 80~300 cm/year of excess siltation at the middle area and both sides, respectively. After artificial dredging which is conducted every two years, siltation had proceeded at a substantial pace, and after some time, the pace has slowed down to its normal rate, going towards equilibrium condition. This research used the siltation pace change acquired from monitoring results to formulate coupled model in order to predict the change of water depth which will take place due to artificial construction of the intake in the future more precisely.

Abstract: As a newly developed engineering structure, bucket foundation breakwater is adapted to soft soil. In this paper, the general-purpose finite element analysis package ABAQUS is employed to conduct three-dimensional numerical analyses on bucket foundation breakwater. Then earth pressure variation on bucket foundation is carried out under different loads of horizontal displacement. Through analysis it obtains the laws of the earth pressure on the meeting-wave side and the back-wave side of bucket foundation breakwater. This will provide the reference and the evidence of preliminary theory for the stability research and practical engineering application of bucket foundation breakwater.

Abstract: Based on the durability investigation on marine concrete structures in South China, the surface chloride concentration and the critical chloride concentration inducing reinforcement corrosion were researched. The surface concentration under the marine environment in South China was analyzed by solid core tests on the harbors with different service ages, and the fluctuation range of surface concentration ranges from 0.2% to 1.1%. Through electrochemical testing and appearance investigation, the value of the critical chloride concentration in concrete components is studied, which is in the range of 0.0518% to 0.0824% by mass of concrete.

Abstract: To verify the resistance to moisture damage of warm mix rubber asphalt mixture, the splitting strength test of warm mix rubber asphalt mixture (WMRAC-13) was conducted under different immersion time and immersion temperature. Test results show that freeze-thaw splitting strength of warm mix rubber asphalt mixture meets the requirement of moisture stability. The immersion splitting strengths in 60°C and 4°C decline with the extension of immersion time. The immersion splitting strengths in 60°C decline faster than those in 4°C. The best fitting function of immersion splitting strengths with immersion time obeys second-order polynomial and power function respectively, and their correlations are the best. The inflection point of attenuation curves is 3th day and 20th day respectively.

Abstract: Quality of steel rail affects directly the running state of locomotive. According to detection problem of rail head’s abrasion loss, a feasibility study was done that collecting image through CCD camera. Computing models of abrasion detection were established by MATLAB soft. The key question about image location was studied using the method of edge detection and image filling. Results indicate that the image detection system could obtain the abrasion loss accurately in non-contact condition. This method could provide a reference for the development of loss prevention and new detection technology.