The air-borne magnetic surveys and rock magnetic measurement were applied to the tunnel site in the granite hydrothermal alteration zone. The results showed the strong magnetic anomaly for the igneous rocks, while the weak magnetic anomaly was found at the hydrothermal alternation zone. Further, the air-borne magnetic survey showed the correlation between the grade of magnetic anomalies and the degree and range of the hydrothermal alteration. But bedrock had been changing rapidly by hydrothermal alteration, the air-borne magnetic surveys did not follow the change. The results in this study indicate that the air-borne magnetic survey technique could be a powerful tool for the first screening survey for the tunnel.

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 Numerical analysis is often used for examining underground excavations, especially under severe ground conditions where rock failure such as rockburst, swelling, or squeezing may occur. Perfectly plastic material models are most commonly used in determining rock failures around excavations even though most rocks exhibit brittle and softening behavior in their post-peak regime. In this study, brittle, lessbrittle and perfectly plastic materials are used in the finite difference study with plane strain condition to examine the effect of the brittleness on unstable failure during tunnel excavation. In addition, the influence of tunnel shape during unstable failure is also examined using the most brittle material characteristics. The major conclusions of this study include: (1) The failed area formed in the numerical model is dependent on the brittleness of the material. (2) Unstable failure such as rockburst can be examined using numerical measures including velocity, acceleration and excess energy in the numerical model. (3) Rectangular tunnel shapes lead to the largest releases of excess energy during unstable failure as compared to circular and horse-shoe shaped tunnels.

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 In this paper, we report on experimental evaluation of the concrete plate reinforced by grid FFU (Glass Fiber Reinforced Urethane) subject to distributed load. First, to clarify the shear capacity of a simply-supported composite beam of concrete and FFU subject to bending moment, four points test was carried out. As a result, the shear capacity of the FFU composite beam almost agrees with that estimated by conventional equation for RC beam. Then we conduct the loading tests on the mortar plate reinforced by grid FFU, subject to distributed load. Consequently, it is found that the shear capacity of the plate can be underestimated by the conventional equation for deep-beam.

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 The diaphragm wall of deep circular shaft is needed to construct a building structure in great depth of large city. The diaphragm wall of deep circular shaft designed lateral pressure is no evidence on scientific fields. From the measurement results of earth pressure gauge and water pressure gauge and reinforcement stress gauge are located on the field, the uneven lateral pressure acting on the diaphragm wall of deep circular shaft, the main factor is bias of water pressure. It is clarified by Iwanami et al. However, design water pressure of current deep circular shaft is adopted as hydrostatic pressure or pore water pressure. Therefore, in this study, is comparing and confirming the measurement results that validity of design water pressure by 3D seepage flow analysis, performing structural analysis for the design water pressure distribution, showing aptitude of design load, proposed the setting method of the design water pressure.

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 In sewer pipeline rehabilitation, it is a common practice to renovate the aging pipe as a composite pipe to resist external forces by forming a reinforcing liner with grouted mortar in sewer pipe. Because the renovated sewer pipe features having old pipe and the special structural form of composite pipe, the structural design is difficult to apply the existing design approach for a common underground structures directly. A design method of composite pipe was developed and has been applied in sewer pipe rehabilitation practice, which applies the nonlinear finite element analysis method and the limit state design concept. In this paper, the design method for sewer pipe renovation is introduced, as well as its verification experiments. In addition, the efect of pre-load acting on the existing pipe is investigated experimentally and numerically, and the validation of the proposed design method is clarifled.

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 Pneumatic caisson method can be widely applied to various ground and has high reliability, while its applicable depth is restricted due to the work under high pressure. To overcome the problem, the pneumatic caisson method employing an unmanned excavation method with helium mixed gas has been developed, which enables the work under pressure up to 0.7MPa. However, the new technology of the pneumatic caisson method for “ultra-great depth” underground space with a groundwater level of 100m will be required to construct infrastructures in urban areas. Therefore, this paper proposes a method to reduce work atmospheric pressure for pneumatic caisson, applying water-sealing technologies at shield tail.

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