Kumamoto Port located on a tidal flat in Ariake Bay is being constructed under uniquely natural conditions; 40m soft ground layer, great tidal range of 4.5m and mild slope of 1/1000. To overcome technical difficulties, engineers have developed and introduced practical use, original technologies and methods such as: a new type of breakwater not requiring foundation improvement even on soft ground (Soft ground dike); the waterway submerged dike, a measure against waterway siltation; and the high-density air-compressed transport process, a method of transporting dredged spoil pneumatically, thus reducing water content in the spoil and thereby preventing marine pollution.

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Harmonizing development and environmental conservation has recently been realized as an important problem to our society. The environmental inpact assessment (EIA) is one of the most efficient ways to solve this problem. This study presents the attempt to restore a marshy valley, which is thought of as an important element of environmental conservation, through the EIA process applied to the Kanagawa University Hiratsuka Campus project. The result is that it is possible to restore a marshy valley on a developed slope, where there was a marshy valley of an abandanned paddy-field before development.

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This paper described groundwater behavior due to the construction of large-scale caverns st Kikuma underground oil storage plant. This paper showed that groundwater behavior during cave excavation is heavily affected by discontinuity of rock masses based on field measurement results. This investigation made it clear that the concept of crack tensor has great potential to quantify the relationship between groundwater behavior and the distribution of discontinuity of rock mass by analyzing the distribution of cracks in rock masses observed at the surface of excavated caverns during construction.

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Concrete-filled tubular steel column with cast steel bearing plates has been recently developed subway station by the unification of conventional tubular steel column and composite column. The following investigations were conducted. 1) Numerical simuration by FEM to analyze the structurally optimum configuration of bearing plates. 2) Experimental study with half-size models. 3) Standardization for practical application. This development has enabled to achieve new economical system as well as to make the construction more simplified.

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In this study, one practical blast vibration estimating method was proposed, taking into account the overlapping holes. In the first step, we proposed that the time delay deviation of the detonator in actual field blasting is larger than the values measured in a factory. On the basis of the former deviation, we calculated the simultaneously blasted hole numbers which produced the same magnitude of blast vibration as produced by the larger number of holes blasted with the same delay number detonators. In the third step, we proposed the new blast vibration estimating method based on the number of overlapping holes. The results confirm the method is more acculate than the usual one.

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We made an attempt on open cutting the ares where a grouting test was provided, and made a search for the critical width of fissure for possible penetrating of grout. This paper also deals with the mechanisms of clogging media for grouting in comparison with 1-dimensional model tests of bricks with a crack. With these investigation and chemical analisys of grout tips from above site, it was shown that clogging of cracks was mainly affected by sedimention of grout.

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The pourpose of this study is to verify the adequacy of an FEM model taking into account soil-structure interaction applied to earthquake response analysis of a bridge pier with a large-scale group-pile foundation. Principally, this paper describes the results of dynamic FEM analyses compared with those of in-situ vibration test using an exciter.
Results from the experiments and analyses are as follows; (1) Coupling resonant phenomena between the ground and the pier are conspicuously observed at the first and the second natural frequencies. (2) Dynamic axial strain which occurs at the top of the piles is transmitted to the end of the piles. (3) The experimental results can be simulated by the two-dimensional analysis model, FLUSH and the three-dimensional analysis model. (4)Inner concretes of the pier show effect of the damping to the pier and the pile foundation under earthquake.

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In recent years, wind-induced cable vibrations of cable-stayed bridges have been observed, and phenomena of these have become a major problem in the wind engineering. In the present paper, the effects of elascity on the damping characteristics of viscous shearing damper are investigated, and the full scale measurements for a actual bridge cable are compared with the results of complex-eigenvalue calculations taken into consideration the elascity in order to examine the damper effectiveness. Furthermore, a simple design curve for estimating the modal damping in stay cables with dampers is proposed from the practical point of view. The use of the design curve is also illustrated through actual examples of bridge stay cables.

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A design method for tunnel to be excavated by NATM in low strength ground is expected to be established. We showed previously that “the tunnel design method for minimum excavation” aimed at achieving the minimum excavation limit is effective for tunnel in low strength ground. It is not unusual, however, that low strength ground is also expansive, and the design and construction of tunnel in expansive ground inevitably depend on trial and error. The behavior of expansive ground can be regarded as creep. In this study, the applicability of the tunnel design method for minimum excavation to ground subject to creep has been investigated.

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This paper presents an impact response analysis for the collision behavior of concrete check dams by using a distinct element method (DEM). The object of this study is to provide the fundamental data for the impact resistant design of concrete check dam under huge stones in the debris flow. At first a concrete check dam sleeve is modeled into circle rigid elements with a spring and a dashpot. The impact response and failure of a model test was simulated by the DEM. Then, the effect of impact absorbing energy is examined for a sand bag on a model of the concrete check dam sleeve. Finally, the damage of actual concrete check dam under debris flow has been simulated by changing the loading condition. It is found that the DEM can simulate well the impact model test in a small scale and the actual damage profile in the case of the loading condition in which a huge stone. dynamic water pressure and the earth pressure are applied.

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This paper describes the weathering durability of fluoropolymer, by analyzing deterioration mechanism of plastics and by evaluating exposure test results. It became obvious that fluoropolymer is superior to other plastics, especially in weathering durability because of its strong bonding energy in molecular structures. Judging from outdoor exposure tests of 0.2mm thickness film and not showing deterioration for a period of about 20 years, the weathering durability of fluoropolymer can be estimated for more than 100 years if it has a 1mm thickness. An outdoor accelerated exposure test (EMMAQUA) was carried out using 2500MJ/m² of UV radiation. The results assures that colored fluoropolymer film has excellent weathering resistant ability with regard to color change and gloss retention. These characteristics of fluoropolymer show that it can be used for various structures and elongate service life and add aesthetic aspects.

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The objective of this study is to compare the constructability of self-placeable concrete with that of conventional concrete and examine its efficiency. Self-placeable concrete developed at the University of Tokyo, in Concrete Engineering Laboratory, could be filled everywhere in the formwork without any consolidation procedure. This concrete possesses the flowability and segregation resistance under fresh concrete and durability under hardening stage. This study discusses about the efficiency of the self-placeable concrete which is applied to the usual reinforced concrete structures.

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The subject of present research is concerned with in-service slopes that collapse due to heavy rain. The authors proposed a procedure to formulate slope collapse or noncollapse judgement system together with the new slope collapse factors, time and rain-fall, in addition to the previously proposed ones. The data used in the analysis are collected from several cut-off slopes constructed on three types of sites (metamorphic, sedimentary and igneous). From these data, the factors that bear an impact on the collapse of slope during heavy rain are clarified and some problematic points are brought under scrutiny in forecasting the slope collapse.

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Carrying up and down a scraper under transportation of soil on a weak sloped terrain, the application height of the effective driving and braking force of a bulldozer could be controlled to obtain the maximum force and the maximum efficiency of power. Several tractive and braking performances of a 50kN weight rubber tracked bulldozer trailing up and down a given weak sandy sloped terrain have been simulated. As a result, it is clarified that the optimum application height is 60, 60, 20, -40cm for slope angle 0, π/18, π/9, π/6rad in driving state, and 20, 0, 100, 100cm in braking state, respectively. The automated control positioning system of the attachment could be developed by use of an inclinometer.

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The purpose of this study is to construct the expert's decision making process, in which judgment whether the value of field measured data with respect to the deformation of retaining wall agrees considerably with the predicted values or not may be made automatically in computer system. In order to simulate the expert's decision making process based on fuzzy set theory, a questionnaire regarding to the above mentioned judgment was set out to 83 experts in excavation work. The results show that the decision making process of expert in excavation work can be simulated by using fussy set theory. It has been also revealed that the expert in excavation work must mainly pay attenion to the five factors.

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One of the recent trends in the area of research on methods of tunneling in urban environments is the use of shields with irregularly shaped cross sections. A series of boring performance tests and tunneling efficiency tests were conducted to verify the effectiveness of a pressurized slurry box shield tunneling machine with a rectangular cross section. The tests confirmed that the box shield tunneling method using the machine is viable. This paper reports on the tests and the evaluation of the test results, as well as the differences between the rectangular shield machine and the conventional circular shield machine.

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