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Tunneling under roadway/railroad in a busy urban area is not an easy work due to a hostile environment involving weak ground and a shallow embedded condition and resulting in a great possibility of tunnel face stability problems. Divided Shield Method (DSM) is one of techniques to reduce the instability of the tunnel face using divided steel plates as a shield for tunneling. This study investigated the effectiveness of layers of the horizontal pipe grouting at the face of DSM tunneling on the stability and construction speed. The investigation was undertaken by the test chamber and its numerical verification. Surface deflection of the chamber fill and the stability of the tunnel face were measured with the excavation sequence. Numerical analyses of the chamber test were conducted to predict further behaviors of DSM tunneling. The results of the study show that DSM tunneling reinforced by horizontal pipe grouting reduced the ground movement and construction time, and enhanced the stability of the tunnel face significantly. Using the test and analysis results, the potential development of a new method that can reduce the construction period was discussed in detail.

Structural vibration design of a pod structure including an optical system installed on a fighter aircraft is very significant in improving accuracy of targeting system to the target objects. To reduce and isolate the vibration generated during the flight, it is crucial to properly design the rubber mount between the pod and the aircraft. In this study, free vibration analysis of the pod is conducted through finite element analysis (FEA) and experiments. Correlations are performed with reasonably acceptable accuracy about the natural frequencies, mode shapes, and frequency response functions obtained by FEA and experiment. Then to optimize the structural dynamics of the pod, three variables are considered, which are mass of the dummies, the numbers of and positions of rubber mounts, and hyperelastic property of rubber mounts. In addition, the position of the pod on the fighter is analysed by FEM to estimate the possibility of further enhancement of its structural dynamics. Finally, forced vibration was undertaken using random signals of a shaker with 1Grms, 2Grms and 2.65Grms considering the test standard. It is found out that frequency responses of the pod are sensitive below 100 Hz to the values of the excitation signals. It is thus indeed to design appropriately the rubber mounts to improve structural dynamics of the pod, which results in the accuracy of targeting system.