The purpose of this study is to propose a quantitative criterion for evaluation from pictures of tunnel lining concrete. Firstly, detailed items for evaluation were set up based on the previous research data. The evaluation grade of each item was decided from the AHP questionnaire of inspectors. The proposed criterion was employed for some actual highway tunnels in order to investigate the applicability. The crack evaluation results by using the proposed criterion were generally correct to results of detailed inspection at site. However, the evaluation for exfoliation of concrete was not always corresponding to the detailed inspection at site.

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Wave-dissipating block removal work is conventionally done by workers or divers using wire ropes. However, the work area is unstable and this work is dangerous. A device for transferring wave-dissipating blocks was developed using net chains to allow for automation and labor saving. Model block transfer experiment and block removal work ware done. The results showed that by adjusting work conditions, the working time efficiency under good visibility situations is 3 min./piece and that for poor visibility situations is about 4-6 min./piece. The cost for transferring a block is about 1/3 of the conventional manual method.

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In this paper, a pavement deterioration model is presented to forecast the progression of pavement deterioration based upon the inspection/rehabilitation data. The pavement performances are described by the multiple rating indices, and the Markov transition probabilities are modeled by multi-staged exponential hazard model. In the processes, a part of samples are systematically dropped by preventive rehabilitation activities. In this paper, a choice-based sampling technique is applied to cope with estimation biases caused by sample dropping. The case study is carried out based upon the rutting progression data observed on the expressways to illustrate the applicability of the proposed methodology.

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In this paper, the road hazards generation processes are modeled as numerical counting processes. The counting processes are first formulated as Poisson processes, and extended to the mixed Poisson processes by incorporating the heterogeneity of the arrival rates of hazardous events. Assuming the arrival rates are subject to the Poisson Gamma distributions, a couple of evaluation indices are presented to measure the road hazard risks. The methodology to find out the patrol frequencies is presented to reduce the patrol costs given the management targets on the road hazard risks. The applicability of the methodology presented in this paper is investigated by the empirical data observed on the national highways.

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This paper focuses on applicability of the cost evaluation method based on geostatistics theory, which authors have proposed, to actual underground construction projects. First, the relationship between cost variation risk, which is defined based on financial engineering theory, and deviation of evaluated cost from actual one has been discussed. Secondly, results of investigation applied the method to two underground construction projects have pointed out that the limitation of the method heavily depends on quality and/or preciousness of in-situ survey. Finally, from a viewpoint of risk management on underground construction projects, the concept of new risk response method, which associates with construction contracts and insurance, has been presented.

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The purpose of this study was to understand the flow properties and permeability of bentonite grout with NaCl added, using laboratory tests, and to clarify the mixing conditions of bentonite as a material. Given that the required permeability of clay grout is 10^-9(m/s), the combination of grout (W/B) becomes 6 or less. The viscosity of the grout was measured, and because the viscosity was higher than the thickest cement milk on dam grouting, it was found that grout with a W/B of less than 10 was difficult to inject into rock joints. We then added NaCl to grout with a W/B is 6, and its viscosity decreased as the amount of NaCl increased. A grout of viscosity able to be injected into rock joints was achieved by adding NaCl in a density higher than ”W: NaCl = 40:1”. Next, the permeability of a bentonite suspension with NaCl was examined using the falling head permeability test. Testing the sample ”B:W:NaCl = 20:20:1” for 10 days revealed that the initial permeability 10^-8(m/s) decreased to 10^-10~10^-11(m/s). These results showed that a suspension to inject into rock joints could be made by adding NaCl, and clarified that permeation of groundwater into the suspension causes a decline in permeability.

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It is efficient to adopt the modern PM concept, such as PMBOK issued by PMI for construction field. In this paper, we carried out the general survey regarding PM knowledge areas for managers, who work for contractors, consultants and overseas, to concern for managing a construction project. Based on the result, we analyzed the efficient management process by using Design Structure Matrix. Furthermore we utilized a graph theory for proposing the efficient construction management configuration as the interdependent management elements should compose a network structure. Our study brought that scope management, communication management & risk management should support the efficiency of overall management.

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In the ground freezing method, the temperature distribution usually exists within a frozen soil wall, because it is made by the row freezing tubes at constant intervals. However, on the usual design technique of the ground freezing method, the strength calculation for setting the adequate safety rate is done by taking based on the average temperature of the frozen soil wall. In this study, the elasticity bending theories of the beams with near temperature distribution naturally, the approximation curve of the temperature distribution and the linear temperature distribution were analyzed, and the results of the elasticity theory for the linear temperature distribution were compared with the experiment data of beams with same temperature distribution at the laboratory examination.

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It is one of the important problems to push forward a disaster prevention business effectively to evaluate danger of dangerous spots for sediment-related disasters. Although it is originally desirable to perform examination based on ground engineering about this, it is very difficult to perform detailed examination individually so that an object point becomes an enormous number. Therefore this study decides to utilize mathematic technique: Support Vector Machine (SVM) and tries to evaluate a risk by learning data of each slope. As a result of having analyzed slope data using SVM, it becomes clear that can evaluate a risk with high precision than a conventional rating method. In addition, we suggest it about a method to evaluate an effect of construction measures using SVM. These results are thought to be very useful in anti-disaster measures.

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A method of dehumidifying the inside of box girders by reducing the moisture of the inner humid air is proposed at Hakucho Bridge. The inside of the girders is highly sealed space, so it could keep dry condition if the moisture taken from the outside is dehumidified. Numerical results indicate that the dehumidifier with 120m³/h capacity can easily dry 3,000m³ space below 40%RH (Relative Humidity). In a large suspension bridge, part of the box girder is sealed (3,200m³), and the dehumidification equipment is installed. It was confirmed that high humid (more than 60%RH) was reduced to 40%RH or even less. A model, which can simulate the humidity change measured in the bridge, is developed and a design procedure is presented.

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The present study focuses on the pavement concrete with high volume fly ash (HVFA concrete). The HVFA concrete develops the flextural strength higher than normal pavement concrete at the age of 91 days. Based on the pavement design method and the present study, the thickness of HVFA concrete pavement becomes thinner than the normal concrete pavement in the same condition. Furthermore the initial construction cost of HVFA concrete pavement is lower than the normal concrete pavement.

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