Soil water coupled analysis of soil behavior under breakwater during water action was performed using SYS Cam-clay model. In fact under cyclic loading, the plastic strain goes on regardless the state of overconsolidation. In this model, the cyclic plasticity was introduced, so that it can be explained the accumulation of plastic strain.
The soil resistance of shear strength under breakwater was investigated supporting the typical clay soil. Acted on the static force to the breakwater, the relation between force and horizontal displacement was shown. Compared with the safety ratio of port standard, some good correspondence was obtained.

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A flume model experiment is newly developed to simulate the wave-induced liquefaction in seabed on a reduced scare of 1: 100, and examine influential factors such as the relative density of seabed on the mechanism of waveinduced liquefaction. This experiment was carried out under these conditions; the depth of water, 17cm, the wave period, 1.0s, the incident wave height, 5.5cm, the thickness of permeable layer, 35cm, and the relative density, _Dr (%), 20-60. In order to satisfy similarity law in 1g gravitational field, the polymer fluid was used to change the permeability of seabed. The main conclusions obtained from this study are as follows; 1) When the relative density is about 20-40%, wave-induced liquefaction due to the increase in residual excess pore water pressure were observed in deep seabed, and shear failure due to wave force were observed in shallow seabed. 2) When the relative density is about 50-60%, wave-induced liquefaction due to the increase in residual excess pore water pressure were not observed in the present experimental condition. 3) Vertical deformation of seabed decreases with increasing density while the shape of seabed surface is similar regardless of the relative density.

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This paper summarizes the state of works have been studied by the Engineering Advancement Association of Japan and the results of the rear metal adsorbent experiments conducted in Okinotorishima-island and Iriomote-island. The adsorbents used in the experiments were developed by the National Institute of Advanced Industrial Science and Technology in lithium and by the Japan Atomic Energy Agency in uranium. The results of adsorbent efficiency in both lithium and uranium were mainly presented in this paper.

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The Port of Shimizu consists of semi-closed estuaries, and the heavy metal content of its water is higher than in open sea water. This contaminant presumably flowed into the harbor where it accumulated in the past. Recovering these contaminants would be extremely costly and energy-intensive, so it is not realistic. So this study examined a method of recovering this contaminant through bioaccumulation by the food chain. The state of sessile animal was investigated and the change over time of the amount of heavy metals accumulated in oysters and mussels that are the dominant species in the Port of Shimizu was surveyed, to set the appropriate recovery time for these sessile animals. They accumulate trace metals in a higher density than in the sea water within the port. Moreover, the sessile animals within the Port of Shimizu port die in larger numbers than during the summer. Therefore, it was assumed that the most appropriate recovery time is the spring season before the sessile animals die, regardless of the amount of trace metals accumulated in their tissue.

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Red spotted grouper Epinephelus akaara is a target species for artificial production and stock because of high market value and their poor migrate habit. But it is feared to decrease for predation and/or starvation immediately after stock. To increase survival rate of grouper seeds, we proposed to stock them into the artificial reefs with shells to provide prey organisms. These reefs were attached the protection units with scallop shells, having achievements as refuge. Results as post-research 8 days after stock, it's suggested that reefs with units have seeds stay as 2.8 times high as without units (24.1% to 8.6% both on the average). Reefs with more complicated units, moreover, could hold 1.3 times more seeds than uniformed ones (29.2% to 23.3% both on the average) and accommodate more various length seeds than smaller ones (F-test, P<0.05). Their gut contents coincided with small animals increasing in reefs. Judging from those results, the institutions are effective for seeds to forage and inhabit as the nursery. We are convinced that this technique makes harbor area strengthen the aquaculture function to insert into the harbor facilities.

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To investigate the possibility of utilization of dredged soil and converter steel-making slag for coastal environmental improvement works, the experimental evaluation of dredged soil mixed with converter steel-making slag was executed. On this study, the following characteristics about mixture were confirmed that strength of soft dredged soil was improved by hydration reaction, the up of pH value of surrounding seawater were controlled, and the quantity of phosphorus elution from dredged soil was decreased. In addition, in the examination for the mix proportion, it was confirmed that f-CaO/W (ratio of quantity of free-CaO and quantity of water in the unit mixture) and D-Si/W (ratio of quantity of dissolvable silicic acid and quantity of water in the unit mixture) were parameters to influence strength of mixture.

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To investigate the possibility of utilization of dredged soil and converter steel-making slug for coastal environmental improvement works, the fundamental evaluation is executed for influence on pH value of surrounding seawater. Strength of alkalinity source was examined by water column experiment for the soil-slug mixture and the converter steel-making slug only. The influence on pH value of the peripheral sea area was evaluated by advection diffusion analysis.

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This paper describes the fall characteristic of the mixture materials in vertical tube. In this paper, the mixture materials were made by clay and converter steel-making slag. As time passed, the cohesion of the mixture materials was growing up, and we measured it by the cylinder flow test. We experimented about the dumping the mixture materials into the vertical tube.
As the result, we found that the mixture materials had three fall conditions which depended on its flow value, and became three accumulated shapes, and that the turbidity from clay and pH from converter steel-making slag were influenced by their fall condition and accumulated shape.

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It is examined to be recycled by mixing the steel slag with dredged clay as base material of the tideland and the structure in shallow water. To confirm the possibility of application as a basic material of such a mixture material and the possibility of construction, the Field performance tests was executed. Dredged clay is mixed with steel slag and it is made to harden. Underwater mounds are made by using the one that the mixtured soil that had become hard was disturbed. To do adequate construction, the indoor examination was executed. The best mixture proportion of dredged clay and steel slag was decided. The effect of controlling the pH and the increase of SS of the mixture material in the sea was verified.

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This paper describes a study on design, management and construction method for dredged soil improvement with converter steel-making slag. After a continuously mixing and damping system was introduced, several tests in laboratory and field experiments were executed. It is found that the density measurement of mixture is available for quality control to keep mixture ratio and a uniform mixture was supplied by the introduced method. In addition, the effectiveness of mixture, decrease of suspended solids under construction, increase of the strength of mixture in situ and little increase of pH just above the constructed mixture mound were confirmed.

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Filter-press technique for dredged clay deposits has been developed, and can produce large volume of dewatered clay lumps. The dewatered clay lump has volume reduction and strength gain. If this lump is used as geo-material for back-filling, the life of disposal pond will be extended.
In this project, a trail construction of revetment backfill is planned and performed in order to confirm the characteristics of dewatered clay lumps. In this paper, the outline of this trial construction is summarized, and the density of backfill and compressibility and shear behavior of dewatered clay lumps are described.

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The large amounts of nitrogen, phosphorus, etc. to be exhausted are causing the eutrophication problem, and it is recognized as a social issue. Moreover, on the bottom of the water stream there is eutrophicated, high density accumulation mud. They cause the abnormal occurrence of algae. Although those substances were transported together with large volumes of water or seawater, the separation of the gas-liquid after the transportation was not easy. Due to the return to the sea of the water which was transportation medium, the micro soil particle contained in that water were diffused in that water area, then this kinds of the method was prohibited in concern with the pollution of the fishery. Then, it is the compressed air transportation to attract much attention. This method has the advantage to be able to transport at high speed by the intermittent flow; “slug flow”, by supplying into the conduit the compressed air and the transportation medium simultaneously. This is the hydraulics study to analyze the phenomena of flowing characteristic and the process of “slug flow”, as a basic research of the technological application of the slug flow.

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In this construction, steel-concrete sandwich structural immersed tunnel constructed by using the semi-selfcompacting concrete for the winter season. In this application, the quality under the degree environment of low temperature of the semi-selfcompacting concrete mixed by the system mixer was checked. Moreover the filling experiment was conducted using the full-scale model which imitated the very narrow division, and the filling performance was checked. In actual construction, the new technologies for semi-selfcompacting and site management were developed and introduced.
These mesures have proved semi-selfcompacting that filling nature equivalent to hi-performance concrete could secure. Therefore, it turned out to steel-concrete sandwich structural immersed tunnel that semi-selfcompacting concrete can apply enough.

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This paper introduces characteristics of observed offshore waves by two sets of GPS buoy system at the Northern Pacific Coast of Japan from April to September in 2007. Very few lack of data appeared during the term, including in the very rough sea conditions caused by typhoon attacks. Offshore GPS buoys observed much bigger significant wave heights in both normal and abnormal sea states than the shallower seabed wave gauges, due to the topographical sheltering effects by peninsulas, meaning that deep-sea wave observation is necessary in order to obtain offshore wave conditions.

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The artificial sea Mountains is a mound installed in the bottom of the sea bed. It used the energy of the flow, and it bring nutritive salts of the bottom of the sea neighborhood to the upper layer. The outbreak mechanism of the effect was complicated, and the lee wave had been confirmed mainly so far.
We could include the other phenomena for this examination and analyzed it in detail, and the method depended on spot observation and numerical value simulation. We was able to confirm the phenomenon that lee wave broke into.
In addition, We was able to confirm the lee wave and interaction of the shear flow.

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The Fisheries Agency of Japan is undertaking a man-made sea mount enterprise in order to increase the fishing resources in offshore area. It is thought that this enterprise leads to fixation of carbon dioxide by photosynthesis of phytoplankton. However, any detail evaluation has not been made on this subject.
Based on the carbon cycle published in the International Panel on Climate Change report on 2007, this paper considered the possibility of carbon dioxide fixation by the man-made sea mount. It was concluded that the man-made sea mount could contribute to sequestrate carbon dioxide by delivering from surface to deep sea.

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In the construction of artificial rubble reef, rubble materials are usually dumped from a barge into the sea directly. The diffusion of materials in the longitudinal direction becomes large in use of the conventional method, which makes accurate construction difficult. In this study, the construction method which uses diffusion-reducing sheets in the longitudinal direction was developed. As a result of laboratory experiment, the effectiveness of the diffusion-reducing sheets became clear. This method was applied to actual construction site with water depth of 85m. As a result, the diffusion in the longitudinal was reduced clearly and the effectiveness of this method was demonstrated.

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In this study, the magnitude of upwelling and resultant convective and mixing zone about the upwelling structure have been examined by the 3-D numerical simulation method. The computation area about the upwelling structure was 2400m long, 960m wide and 200m deep. The finite differential method was applied for the discretion. The marker layer of 14m thick was placed on the bottom in order to visualize the upwelling. We have adopted three different shapes of upwelling structure, such as I-shaped, V-shaped and X-shaped plates in the horizontal plane.
Based on the results on a series of numerical experiments, it has been revealed that the most effective structure is the V-shaped plate for generating the upwelling and resulting mixing in the 3-D flow field. It is also seen that the vortices are generated from both wing edges of the V-shaped structure. The analysis on the V-shaped structure with various heights and open width and angles was carried out for the most effective structure.

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The Naha-harbor in Okinawa-Prefecture is located in a coastal region with coral reef where the wave transformation due to wave refraction, diffraction, shoaling and breaking are induced. The present harbor planning has been carried out employing only the wave diffraction calculation with a uniform water depth. Therefore the wave heights designed in some quay walls may differ from the practical wave situation. In the paper, a new wave simulation in the harbor area is carried out employing the new Boussinesq form named NOWT-PARI to evaluate the effect of an offshore permeable type breakwater with good accuracy. The simulated results are validated by the field observation carried out after the implementation of the breakwater in 2007.

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In many ports in Japan, long-period waves cause disturbances of cargo handling and breaks of mooring ropes. We developed a new type of long-period wave absorption structure which involves two oblique walls and a vertical slit between them. The performance of various structural types of them has been examined by two dimensional hydraulic experiments.
In this paper, the performance when installing proposed structure in an actual port is examined. We study the effect of the proposed structure to reduce standing wave height in the harbor by three dimensional model test and numerical experiment using boussinesq equation.

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This study examines how to assure safe mooring under influence of long period waves and swells for a passenger ship (50, 142GT) and a large wood-chip carrier (40, 245GT) by means of numerical ship motion simulations. In the Port of Shingu, an offshore breakwater is still under construction, which allows the incident waves from the outer sea to reach the quay wall (depth of the water 11m) directly depending on the wave direction. This requires urgent countermeasures against unfavorable motion of the moored ships at the wharf in the port. The purpose of this study is to discuss how to secure safe mooring, considering progress of the breakwater construction.
As a result of the study, it is concluded that, while the breakwater should be completed as soon as possible, installation of air-type fenders on the existing quay wall makes mooring of the examined vessels safe even before completion of the breakwater.

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Infragravity waves are generally analyzed as components whose frequencies are more than thirty seconds. As many components are included in the frequency area, it is necessary to clarify the characteristic of each component.
We analyzed wave height data of four components (30-60s, 60-300s, 300-600s and 600s-) of infragravity waves compiled by NOWPHAS system. This study reveals that the characteristics of infragravity waves are very different depending on frequencies and sea areas. The wave height longevity of the longer component (600s-) is smaller than those of shorter components.

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To estimate long period ship motions in harbors, specific wave information like long wave spectrum is more useful than the mean value like information such as the significant wave height and the significant wave period. As for wave field calculations in harbors, so-called Boussinesq's model seems to be widely used because of its versatile features. However, it hasn't been clarified yet about how large the sponge layer should be taken to simulate open-sea condition; how long the computation should be continued to obtain statistically stable spectrum; what size of the computational area should be considered, etc. In this study these basic conditions were investigated by conducting wave field simulations by Boussinesq's model. Useful information was obtained such as: the data length, from which the spectrum is calculated, need to be longer than at least 5 to 6 hours to get a stable spectrum; the length of the sponge layer could be much less than the length expected from one-dimensional calculations; the size of computational area doesn't affect the results so much if it is as large as the one empirically taken in computations.

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The current measurements have been carried out by NOWPHAS at several stations in the coastal area around Japan since 1996. In the data, temporal but simultaneous changes in residual currents were recognized at several stations in the Japan Sea side. The cause of this temporal change was deduced to be due to the strong currents caused by typhoon approach. In this study, attention was paid especially on the period of typhoon approach, and the occurrence characteristics of the strong currents in the offshore area was investigated based on the data of wind speed, the atmospheric pressure and the typhoon track provided by Japan Meteorological Agency.
As a result, it was found that typhoon approach contributes to the generation of the offshore strong current in many cases. In addition to this, it was also found that the current velocity increases in the area where wind blows for a long time in the same direction. Furthermore, it was also observed that the strong current is likely to appear at more than two stations during the typhoon.

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On September 6, 2007, rough waves with a significant wave height of 6 m and wave period of 14 s due to typhoon 0709 attacked the Shonan coast. After the wave attack, scarp was formed in an extensive area of the coast, where beach nourishment has been carried out. Many surfing grounds on the Shonan coast, where is famous at surfing, were damaged by this wave attack. These damages in terms of coastal protection and surfing were investigated through the comparison of the shoreline changes and changes in longitudinal profiles as well as the analysis of the wave information for the surfers. As a result, although the shoreline was kept intact, bar formation was confirmed due to offshore sand transport. It was found that the surfing grounds were significantly affected by this offshore sand movement, but the total sand volume in the zone shallower than the depth of closure (9m below the mean sea level) was maintained.

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A real-time forecast system for storm surges and waves in Ariake Sea is developed to include wave runups and overtopping discharges as more appropriate warning system for the residents. This real-time warning system consits of simplified and suitable tuned theoretical and empirical prediction models. In the system, runup predictions are carried out the Savile's method of which validity was checked by employing the numerical model called as the CADMAS-SURF for cases applies to the target condition in the Ariake Sea area. By using this system, administrators can make decisions evaculation in advance. However, it is still necessary to develop more sophisticated and valuable information as the warning system.

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Three major bays in Japan have large low-lying lands. Inundation damage there by storm surges is increased by sea level rise and typhoon strengthening due to global warming. For estimating this damage, numerical models that describe storm surges, waves and inundation were built up. Then, damage graphs that output damage index from sea level rise and typhoon strengthening were drawn based on calculations by the models. The graphs showed that inundation area, inundated population and amount of loss increase rapidly at typhoon strengthening ratio 1.0to 1.3.

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A new scheme of numerical simulation of storm surge has been developed recently. With this simulation model, abnormally high storm surges generated by large typhoons around the coasts of Japan were well reproduced. Furthermore, numerical simulation model for storm surge inundation is developed to study and prevent storm surge disasters on Japanese coasts. Inundation simulation method induced by overflow, overtopping and dike breach is incorporated into this model. With this inundation simulation, coastal protection works consisted of hard and soft countermeasures can be designed. This paper presents the application to Ise Bay.

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Cyclone Sidr passed on the southwestern part of Bangladesh and induced storm surge disasters affecting 8.9 million people in November 15, 2007. From the point of disaster mitigation on storm surges, we surveyed damages of this disaster and assistance needs for recovery in damaged areas. Long stretch of river embankments was eroded by overflowing during the storm surge. Cyclone warning was transmitted to many people through the system based on Cyclone Preparedness Program. Continuous disaster education and succession of disaster experiences are important as well as improvement of river embankments.

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This paper aims at establishing the level-one reliability-based design method for jacket type wharves. The target reliability indices for jacket type wharves were set as the same level of pile-supported wharves. Then, the sensitivity factors of the members of jacket type wharves were classified into four categories from the viewpoint of similarity of the values of sensitivity factors. Furthermore, the partial factors were evaluated by using the target reliability indices, sensitivity factors, mean and standard variation of parameters. Finally, the applicability of partial factors was assessed by checking the result of partial factors design method.

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This paper aims at discussing the reliability indices for the members of jacket type wharves designed by conventional design method. First-Order Reliability Method was used for the calculation of the reliability indices for conditions under level-one earthquake ground motion, berthing and traction.
The results of the analyses indicate that the reliability indices for the members of jacket type wharves have larger dispersion than those of the pile-supported wharves. For conditions under level-one earthquake ground motion, the average reliability indices of can, brace and upper-pile are larger than those of pile at undersea and lower-pile. Reliability indices for the latter are less than those for pile supported wharves. For conditions under berthing and traction, the reliability indices are almost the same level as those for the pile-supported wharves.

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The reliability-based design method is the standard design method for the technical codes for port facilities. Determination of target failure probability is very important on the reliability-based design.
In this study, the sliding failure of the caisson type breakwater (composite type breakwater and breakwater covered with wave-dissipating blocks) is treated in view of sliding displacement. First, survey of the latest design wave condition including extreme probability condition is conducted. Characteristic of design wave condition in each area is analyzed. Next, failure probability for caisson type breakwaters designed by conventional design method is estimated in view of sliding displacement. Finally, target failure probability is optimized in order to apply the reliability-based design to practical design using the latest design wave condition.

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In order to confirm the effects on stability of structure and external force acting on the leaning type retaining wall, this sensitivity analysis is conducted. As a result of the analysis, a backwash, which is traditionally not considered as an active element, actually has a considerable impact on the leaning type retaining wall. Therefore, we have been measuring the wave forces and we also have found out the mechanism of destruction acting on the new type retaining wall by the hydraulic model experiments. This new type retaining wall will bring better results on Hiroshima harbor development plan.

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In this study, fluid motions in the joint gap of caisson-type breakwater are investigated experimentally. This study focuses on a random wave attack as incident wave and discusses: 1) whether fluid resonance occurs in the gap; 2) the conditions at which fluid resonance occurs; 3) the scale of wave heights in the gaps at the resonance.
In the experiments, fluid resonance occurred in the gap under random wave as fluid resonance happened under monochromatic waves. The appearance of fluid resonance under random waves depended on the resonant frequency at which fluid resonance occurred under monochromatic waves. Furthermore, the amplification of wave height in the gap was linearly proportional to the relative frequency spectrum at the resonant frequency.

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The flexible bulkhead such as anchored sheet pile wall is often employed for soil retaining work of port facilities in Japan. In recent years, existing sheet pile walls are requested to be reinforced for maintenance and to be functionally enhanced for large ships. To meet these requests, a reinforcement method called dual-anchored sheet pile wall, in which the second anchorage work is to be attached to the existing anchored sheet pile wall, is expected. The design method of dual-anchored sheet pile wall, however, has not been established. In this study, model tests of the dual-anchored sheet pile wall were conducted in order to understand its behaviors. This paper describes the effect of the additional anchorage work to reduce the load acting on the existing anchored sheet pile wall, such as the bending moment of the sheet pile and the tension of the tie rod.

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A caisson with a rear parapet is advantageous because the wave force acts on the caisson and the parapet having a time lag, so that the total wave force becomes smaller. However, the wave force acting on the parapet was not well investigated, especially the impact wave force was not clear when the caisson locates in the surf zone. We carried out hydraulic model experiments to investigate the characteristics of the impact wave force on the parapet.
The experiments showed that the shape of the wave at the front of caisson varies wave force widely and the water splashed from the edge of the caisson makes large force on the parapet. Though the observed wave force changed when the tests repeated, the largest wave pressure acting on the parapet was about 3ρgH_max and it acted evenly from top to bottom of the parapet.

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In recent years, there have been an increasing number of projects that adopt “sloping top caisson breakwater” to reduce construction cost. It is however known that this type of structure tends to increase transmission coefficient of wave. Accordingly, this study was conducted to elucidate transmitted wave characteristic about “sloping top caisson breakwater with upright-wall in the rear” of hydraulic model tests. The basic data obtained is expected to be greatly helpful in future breakwater design.

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A set of experiments was conducted to examine the stability of new type of wave dissipating blocks. It was confirmed from the experimental results that offshore wave steepness influences the stability of blocks. The parameters of stability number formula were derived with classification of wave steepness. Required weight of new block against a design wave can be reduced to 90 percent compared to a typical standard block because the stability is being improved. The wave steepness relates deeply to the breaker type, and wave steepness' effect should not be neglected in the stability estimation of blocks. In order to separate the effects of wave steepness and wave breaking, it had better to conduct the experiments with flat bottom condition for further investigation of blocks' stability.

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Authors have developed the offshore structure for control of sea environment named S-VHS construction method, which is composed of the sloping top slit-type caisson and steel pipe piles. The sloping top form enables to realize the remarkable reduction of wave force exerted on the dike body compared with the conventional one.
In this paper, hydraulic feature with wave dissipation ability and wave force reduction effect are verified through some hydraulic experiments. After the preliminary study for the valid structure form, reflection and transmission ability for the selected structure models were tested with the hydraulic experiment relevant to the ratio of caisson width and wave length. Finally, wave force experiment was executed and it revealed the performance of wave force reduction. Based on the results, we proposed specific design wave force formula for S-VHS construction method.

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近年台風災害の頻発が上がりました。2004年10月20日に台風トカゲが西周参見の防波堤を破損しまりました。Kim et al. (2005) はこの破損の記録をとりました。本論に西周参見の防波堤の破損は算出記載する。Esteban et al. (2007) は波浪の作用によって生じるケーソン式防波堤のマウンドの変形手法を提案した。ブシネスクの解を使用する簡便な土質力学の理論を適用することで, ケーソン式防波堤の鉛直と滑り込み (Sliding) 変位を予測する。

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Many of port facilities in Japan were constructed in 1960s, so most of them will be renewed or repaired in 10-20 years. To carry out these renewals and repairs with budgetary limit, reduction of life-cycle cost and/or extension of life for each of these facilities shall be required. Therefore the preventive approach is to be put into the manner of maintenance for port facilities.
Ministry of Land, Infrastructure and Transport updated the ordinance on the technical standards for port and harbour facilities in Japan in 2007. The updated ordinance requires that owners of port facilities shall establish a maintenance plan for each of them, and manage it adaptively according to the plan.
This report shows a practical procedure of the preventive maintenance approach according to the updated ordinance, and gives some examples of the preventive maintenance. Also in this report, issues in carrying out the preventive maintenance and their measures are discussed.

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Many of port facilities in Japan were constructed in 1960s, so most of them will be renewed or repaired in 10-20 years. To carry out these renewals and repairs with budgetary limit, reduction of life-cycle cost and/or extension of life for each of these facilities shall be required. Therefore the preventive approach is to be put into the manner of maintenance for port facilities.
Ministry of Land, Infrastructure and Transport updated the ordinance on the technical standards for port and harbour facilities in Japan in 2007. The updated ordinance requires that owners of port facilities shall establish a maintenance plan for each of them, and manage it adaptively according to the plan.
This report shows the analytical procedure of life-cycle cost for port facilities. Parametric study of this analytical method is carried out to provide the effect of preventive maintenance on life cycle cost for each part of each facility. Based on the result of this parametric study, the effect on whole life-cycle cost for port facilities is also discussed.

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The purpose of this study is to develop of detective method for degradation under paint film using exposure sample. Fundamental experiments for development of nondestructive evaluation method by using characteristics on propagation of low-frequency waves in coating thin plate were carried out. The proposed detective method applied distribution of response of deflection amplitude at degradation part and no degradation part in coating thin plate model to low-frequency incident wave.
The distinct responses of deflection amplitude at degradation part and no degradation part were obtained although using low-frequency waves. The results of the experiments show that it is possible to detect for degradation in coating thin plate by proposed nondestructive evaluation method.

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Japan's coastal protection facilities were developed with the intention of protecting those cities behind the coastline from natural disasters such as high water, tidal waves, tsunamis and erosion. The majority of these facilities were constructed until the 1960s and hence have suffered damage and deteriorated functioning due to aging of materials and the force of the waves. This being the situation, the government and various local bodies must work within their straightened fiscal circumstances to effectively diagnose the degree of degradation, improve functioning as appropriate and perform maintenance. This study has ordered the relationships between the causes of the facilities deformation and the countermeasure construction methods as well as verifying their validity, thus enabling the correct countermeasure construction methods to be selected.

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The technical management of old and age-advancing concrete armored coastal dikes to function longer is currently required. The purpose of this investigation is to discuss the number, location and width of cracks occurred on the parapet of old concrete armored coastal dikes along Mikawa Bay, by means of field measurement. The field measurement shows clearly that the crack width increases with advancing age of the coastal dike and that number of cracks increases as the design wave height becomes higher. The crack is found out to increase remarkably on the parapet length of9.5m-10.5m. The crack width of the banking-type coastal dike constructed more than 40years ago is revealed to be 1mm-73mm, which is much larger than 1mm-15mm of the retaining wall-type coastal dike constructed 23-28years ago. In addition, with increasing number of cracks, crack-occurrence locations are found out to be spread from central part to overall the parapet crown.

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We are executing Tokushima airport expansion project, what is to extend the runway from 2, 000m to 2, 500m to enable the larger airplane to take off/land, and what is the relocation of passenger terminal facilities. In this project, it is required that the area is rapidly reclaimed about 40 hectares in short period of 4.5 years. Under the situation of such a large-scale, and rapid construction, accurate reclaiming design on the minute settlement presumption that considers functionality, economy, and constructional is demanded. This paper reports the interim results of settlement analysis based on monitoring while reclaiming this area.

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In this study, a low reflective dike that aims sea water mixing and diffusion along the vertical direction in a semiclosed bay is intended for development through the use of wave energy as a driving force. A water chamber type dike comprised of a row of vertical walls of different drafts and a submerged horizontal plate was proposed as a typical structure in order to be able to utilize piston mode wave resonances and resultant vortex generations for the effective vertical mixing. Especially, a wedge section of the front wall was adopted to induce the mean current along the vertical direction of the structure as a resultant effect of asymmetrically generated vortex flows at the mouth of the water chamber. Additional function of the structure as a low reflective dike was also examined.

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For the economical construction of breakwaters in relatively deep sea ports, we have already proposed a jackettype breakwater with water chambers consisting of more than two vertical walls and one submerged horizontal plate. In the practical application of pile supported breakwaters of this kind, inclined support piles are usually adopted because of economical points of view. In such a situation, the shape of the water chamber may become trapezoidal because of inclinations of support piles. In addition to the rectangular-shaped water chamber, the trapezoidal-shaped water chamber was used for a jacket type breakwater. Hydraulics performance of the breakwaters, such as reductions of transmitted waves and water exchange abilities etc., is examined experimentally and theoretically.

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Ofunato Bay has tsunami protection breakwaters at the mouth of the bay, which decrease a bay-water exchange rate to outside and degrade the water quality. The strong density stratification has been formed in summer. These environments have been said causes of hypoxia and eutrophication in the bay. In order to manage the bay environment, an enhancement system for bay-water exchange rate using natural energy has been implemented on the tsunami protection breakwaters since September, 2004. Enhancing mixing of surface and bottom water by flux control was a target of this system. After the implementation, continual monitoring has been done. It showed pumping discharge upward and downward by wave, tide, and oceanic water intrusion. The intensity of the discharge could be formulated as a function of approaching velocity and stratification of the bay.

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Sea water pollution in a fishery harbor is one of serious problems in fishery industries. Safety of sea foods is heavily dependent upon the quality of sea water in a harbor and its neighboring sea area. On the other hand, since a fishery harbor is a base for fishing boats and vessels, the tranquility of a harbor basin must be securely controlled by the surrounding breakwater system. In order to solve the above mentioned contradictory problems of the fishery harbor, we have proposed and developed a new type of sea water exchange breakwater, which has a wave control function as well as water exchange function. In this study, performance of the newly developed water exchange breakwater in the model harbor basin was examined extensively, such as a water exchange function and wave sheltering effect for various water-exchange breakwater allocations. It was confirmed that five water exchange breakwaters were sufficient to exchange sea water in the model basin for given nominal wave conditions.

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