The usage of TBM is growing gradually in South Korea with an increase in tunnel constructions in urban areas. TBM is suitable for tunneling in urban areas, while below the surface of the streets, unexpected anomaly zones exist, such as core stones, weak, mixed, fault and fractured zone, along with numerous obstacles such as water and sewage tunnels, deep foundations, cable tunnels, and metro lines. Therefore, it is important to predict ground conditions ahead of the TBM face for safe and economic tunnel construction. In this study, we developed a method to predict ground conditions ahead of the TBM face using electromagnetic waves. Unknown parameters such as ground conditions (size, state, location of anomaly) can be predicted from multiple measurements via back analyses. The developed method was verified through field tests.

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The design and construction of the tunnel intersection is one of the critical part of tunnel projects .This paper present a numerical analysis of static behavior of Hakim tunnel intersection that is located in Tehran-Iran. Hakim tunnel is located in 22th quarter region Hakim highway. The tunnel consist of two distinct path ways went back which has three lines on each side. The intersection consist of two tunnel excavated with New Austria Tunneling Method (NATM). Geotechnical-structural-geodetic instrumentation as a practical engineering tool for systematic monitoring of tunnels and buildings in urbanized area were placed and layout of Hakim tunnel monitoring plan considering all requirements were planned and implemented. The NATM tunneling method is considered in numerical analyses. Extreme care is taken during excavation and immediate application of support media prevent unnecessary loosening of media. Many countries have adopted this method as the primary method of construction. This method is selected in this project. Based on special characteristics of Hakim tunnel, an extensive monitoring program has been developed for this project especially in junctions. In Hakim tunnel, monitoring process contains a plan of instrument installation (shallow and underground instruments) and reading plan. A 3d finite element model is implemented simulate the construction procedure with using FE based soft –ware ABAQUS. An elasto- plastic model with mohr-columb failure criteria is used to present the stress-strain soil and shotcrete behavior. In this model shotcrete is used for the support tunnel after excavation. The surface settlement, deformation of tunnel crown and forces in shotcrete due to excavation of intersection area has been studied. The results showed that the upper area of shotcrete in main tunnel is critical section for design support. In order to verify the accuracy of finite element model the results are compared with field measurement

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Shield tunnelling technology has been widely applied in various ground conditions to minimize the change and possible damage of an area in which a tunnel is intended to be constructed. Subsequently, Horizontal and Vertical shield (H&V shield) machine technology has been developed from common shield tunnelling method by connecting two ordinary articulated shields between left and right body. The H&V shield machine can rotate multi-circular tunnel shape continuously from horizontal direction to vertical one or vice versa under simultaneous construction of multiple tunnels. Consequently, H&V shield machine technology is precious for saving cost, reducing time and increasing construction performance at tunnelling. Simulation algorithms based on the shield kinematic model were utilized to simulate the shield tunnelling behaviour. This paper examines the influence of copy cutter length (CCL) on H&V shield behaviour by a sensitivity analysis. As a result, it was found that the copy cutter length has more effect to the shield behaviour, especially in velocity and pitching angle, because the increase of copy cutter length (CCL) reduces ground reaction force.

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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.

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Recently, shield TBM is widely used for shallow tunnel, super long tunnel, downtown area where blasting method cannot be applied, as well as subsea and riverbed tunnels. A case study on the design and construction for shield TBM tunnel which is the construction case of tunnel underpassing the Han River would be explained in this paper. TBM tunnel on this site was designed on the basis of the results of preliminary geotechnical investigation. The dimension of tunnel is 45m of maximum depth, 15m of maximum water depth and total length is 1,497m. Tunnel diameter is 3.01m, equipment type is EPB and segment thickness is 20cm. In this case, the advance rate of shield TBM fell short of its designed advance rate due to the geological condition which is consist of multiple layer(i.e., high water pressure layer including sand and gravel layer) and is different with the designed condition. As a result of efforts to overcome the unexpected difficulty, the construction was completed safely securing the stabilities of the tunnel. On this paper, application of shield TBM in the gravel layer with high water pressure case will be introduced based on the data for solution to overcome the difficulty in tunnel excavation.

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Sixteen 1/30-scaled static centrifuge model tests and an elastic FE analysis were conducted to investigate the seismic behavior of buried culverts. In the tests, four model culverts (arch-type, box-type, and circular-types with different flexibilities) were buried in different types of model grounds. Distributions of normal and tangential earth pressures acting on the surfaces of the model culverts, as well as those of bending strains produced on their walls were precisely measured during 10 cycles of simple shear deformation of the model ground with the maximum shear strain of 3.2 %. The elastic FE analysis that allows slip and separation at the culvert-ground interface generated results that were in good agreement with the experimental results, confirming the validity of the analysis. On the other hand, the current Japanese seismic design standard using seismic deformation method based on spring model predicted distributions of earth pressures and bending moments on the model culverts that were different from the experimental and the analytical ones, revealing that the standard regards the mechanism of seismic soil-structure interaction incorrectly. Thus, the FE analysis is recommended to be used as an appropriate seismic design method of buried culverts, instead of the problematical current design standard.

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